Htitt QfolUge of J^gntultuw At CJotncll UniacrBitH JItliata, 9?. $. Cornell University Library SF 201.A73 5thed. Manual of cattle feeding.A treatise on t 3 1924 002 955 395 The original of tliis book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924002955395 MANUAL OE CATTLE-FEEDING. A TREATISE ON THE LAWS OF ANIMAL NUTRITION AND THE CHEMISTRY OF FEEDING-STUFFS IN THEIR APPLICATION TO THE FEEDING OF FARM-ANIMALS. With Illustrations and an Ajopendix of Useful Tables. \ By henry p. f RMSBT, Ph.D., FBSBIDEIIT AND DIRECTOR OP THE PXNNSTLTJUilA STATE COUiEaB (AORICDI.TnBAI. EXPERIUEHT STATION). FIFTH EDITION. NEW YORK: JOHN WILEY AND SONS, 53 East Tbnxh Stbebt, ' SecsDd door vest of Broadway. 1890. COPTBIOHT, JOHN WILEY & SONS. 1880. PEEFAOE, Investigation into the laws which fomf the basis of the ra- tional feeding of live-stock has been most actively and indus- triously carried on of late years, and very important advances have been made, especially in Germany, where this branch of applied science has been most attentively and persistentiy studied. The period since the year 1860, in particular, has been a remarkably fruitful one ; within this period the theory of feeding has been placed on a firm, scientific foundation, and the direction of its future progress has been marked out ; and while very much still remains to be done, the results already achieved are of great practical importance. Unfortunately, however, these results are largely inaccessible to the majority of American feeders, and those of them which appear from time to time in agricultural papers and other publications are deprived of much of their good effect by their necessarily fragmentary character. It is the object of this work to present these results in a connected and systematic form to American farmers and others interested in stock-feeding, an attempt which, so far as the vmter is aware, has not before been made, and a few words as to the scope and aims of such a book wiU therefore be in place. iv PREFACE. In the writer's view, the highest usefulness of a work like the present does not consist simply in giving receipts which shall enable the fanner to feed his stock more economically, or to pro- duce more milk or more or better beef, but in so elucidating our knowledge of the unchanging natural laws, chemical and physiological, of the nutrition of animals, that the attentive stu- dent shall be able to adapt his practice to the varying conditions in which he may be placed, and, more important still, shall be able to appropriate intelligently the results of new investiga- tions and foUow or take part in the advances of the science. Guided by this idea, the author has not been content simply to state results, but has endeavored, so far as was possible in an elementary work, to indicate the processes by which these results have been reached and the degree of certainty which attaches to them, as well as to point out the directions in which our knowledge is still deficient. Only in this way can a cor- rect idea of the present state of the science be obtained or the learner be prepared to appreciate and utilize further progress. In this the chiefly practical importance of the subject has not been forgotten. The idtimate object of this branch of applied science is, of course, to enable us to feed better and more economically ; but the only sure and lasting foundation for a rational practice is a knowledge of the natural laws on which it is based, and with which it must be in accordance in order to be successful This method of treating the subject naturally makes demands for study and thought on the part of the reader ; the results of twenty years of arduous scientific work by scores of investi- gators are not to be grasped and appropriated vdthout labor. At the same time the author has endeavored to reduce this PEEFACE. 7 labor as much as is possible without the sacrifice of accuracy and a reasonable degree of fulness. Above all, he has sought to make his work a reUable exponent of the present state of knowledge on the subject of cattle-feeding, and to draw a sharp line between proved and useful facts, and merely probable hypotheses or speculations. This book was begun as a translation of Wolff's " Land- imrthschaftlidhe Fiitterungslehre," a volume of some two hun- dred pages. It was soon found, however, that considerable additions and changes were required to suit it to Ameri- can readers, and the work has finally assumed its present form. Some portions of it are stiU free translations of Wolff,' but much more of it has been either added or entirely re- written, and a number of illustrations have been introduced, so that the character of the book has been considerably altered. One of the most marked changes is the substitution, in the Appendix, of KUhn's tables of the composition and digestibility of feeding-stuffs for those of Wolff Although the writer does not accept all of Kiihn's opinions, he yet beUeves that tables arranged on the plan adopted by Kiihn are, on the whole, preferable to those c6ntaining simply aver- ages ; and in view of the changes and additions made else- where in the volume, he has felt justified in making the sub- stitution named, though aware that Kiihn's views, on some points, are warmly opposed by Wolff. In addition to the " Futterungslehre," the author is espe- cially indebted to Wolff's larger book, " IHe Emdhrung der landwirthsckaftlichen Nutzthiere," whUe other works and the current literature of the subject have been freely consulted. Sept. 1, 1880. TABLE OF GOI^TENTS. PAOB INTHODTICTION 1 PART I. THE GENERAL LAWS OP ANIMAL NUTRITION. CHAPTER I. — Thk Composition op the Animal Body . . 6 § 1. Proportions of the yarious tissUes .... 5 § 2. Non-nitrogenous matters 7 § 3. Nitrogenous matters 14 § 4. Inorganic or non -volatile matters ... .20 CHAPTER II. — Components op Fodders — Nutbibnts . . 25 g 1. Definitions 25 § 2. Nitrogenous nutrients .26 § 3. Non-nitrogenous nutrients 38 § 4. Inorganic nutrients 47 § 5. Fodder Analysis ....... 48 CHAPTER III. — Digestion and Resobption .... 54 § 1. Digestion 54 § 2. Resorption 66 CHAPTER IV.— CiECULATioN, Respiration, and Excretion. 74 § 1. Circulation 74 § 2. Respiration 80 §3. Excretion 93 vm CONTENTS. CHAPTER V. — Methods op Investigation . § 1. Determination of digestibility § 2. Determination of nutritive effect of a ration CHAPTER VI.— FOBMATION op Flesh . § 1. Introductory § 3. Organized and circulatory protein . § 3. Feeding with protein alone § 4. Feeding with fat or carbhydrates alone . § 5. Feeding with protein and fat § 6. Feeding with protein and carbhydrates . § 7. Nutritive value of amides . . . • § 8. Influence of quantity of food . CHAPTER VII.— The Fokmation op Fat § 1. Sources of fat § 3. Feeding with fat alone § 3. Feeding with protein alone .... § 4. Feeding with protein and fat .... § 5. Feeding with protein and carbhydrates . § 6. Influence of other conditions on the production fat CHAPTER VIII.— The Production op Woek § 1. Effects of muscular exertion on excretion § 3. The source of muscular power § 3. Internal work of PAGB 104 104 109 119 119 123 138 136 137 143 158 167 169 169 187 188 189 191 198 303 304 313 326 rAJRT II. THE FEEDING-STUFFS. CHAPTER I.— Digestibility 243 § 1. Digestibility of the nutrients of coarse fodder . . 345 § 3. Circumstances affecting the digestibility of coarse fodder 259 § 3. Digestibility of the concentrated fodders and their influence on that of coarse fodder .... 873 CHAPTER II.— The Coakse Foddebs 288 § 1. Meadow hay, rowen, and pasture grass . . . 288 CONTENTS. IX §2. Thele^mes 301 Clover and clover hay 303 Lucerne 307 Vetches .... ... 309 Lupines 310 Other legfumes 311 § 8. Hungarian grass 314 § 4. Maize fodder and stover 315 § 5. Tops of root-crops 321 § 6. Straw of the cereals 323 § 7. Straw of the legumes 336 § 8. Chaff, pods, and maize cob 327 CHAPTER III.— CONCENTKATED FODDERS .... 330 § 1. The grains 330 § 3. Bye-products of the grains 337 § 3. The legumes 343 § 4. Oil seeds and oil cake 345 § 5. Animal products 349 § 6. Tubers and roots 355 PART III. THE FEEDING OF FARM ANIMALS. CHAPTER I.— Feeding Standards . 305 CHAPTER IL — Feeding fob Maintenance § 1. Oxen § 3. Sheep CHAPTER in. —Fattening §1. Cattle. § 3. Sheep . §3. Swine. CHAPTER IV.— Feeding Working Animals § 1. Introductory .... § 3. Working oxen .... §8. Horses 374 374 383 393 393 399 404 407 407 408 409 C0NTEKT8. CHAPTER v.— Production of Milk § 1. The milk-glands and their fnnctions § 2. The quantity of milk § 3. The quality of the milk . § 4. The feeding standard CHAPTER VI.— Feeding Giiowing Animals § 1. General laws of the nutrition of young animals . §2. Calves § 3. Lambs §4 Pigs § 5. Inorganic nutrients CHAPTEE VII.— The CALCtJLATioN of Eatioks PAGE 414 414 419 426 431 436 436 442 448 458 462 466 APPENDIX. Table L — The composition of feeding-stnSs .... 478 Table II. — The digestibility of feeding-stuffs . . . 487 Table IIL — ^Feeding standards for farm animals . . . 492 Table IV. — Proportions of the vaiions parts of cattle, sheep, and hogs 494 MilUAL OF CATTLE-EEEDING. INTEODUCTION. The two objects of agriculture are the production of plants and of animals. We must seek for the laws governing the former in the chemistry and physics of the air, the soil, and manures, and in the phenomena of vegetable growth ; while a scien- tific study of the latter involves a consideration of the laws of animal nutrition and growth, and of the chemistry of plants, so far as they are used as food. All forms of life with which we are acquainted, vegeta- ble as well as animal, manifest themselves through the breaking up of more complex into simpler compounds, accompanied by a liberation of energy. The broad distinction between vegetable and animal life is, that plants are able to appropriate the force which ex- ists in the sun's rays and use it to build up these complex compounds out of very simple, so-called inorganic mate- rials, whUe animals lack this power, and are obliged to avail themselves of the compounds already formed by plants. In the economy of nature, the office of the plant is to store up energy from the sun's rays in certain complex compounds, setting free oxygen in the process ; while the 1 2 HAirUAL OF CATTLE-KEEDING. animal takes these compounds and ntilizes the latent en- ergy which they contain for his vital processes, the sub- stances themselves uniting again with the oxygen from which they were separated in the plant. In the plant the spring is wound up — in the animal it imwinds and gives out just as much force as was used in winding it up. The two processes supplement each other ; the whole is a com- plete circle. A living animal, then, is constantly decomposing and oxidizing the materials of its own body. These first break up in the cells of the body, independently of oxygen, in accordance with the laws which regulate vital phenomena, and give out part of the latent energy which they con- tained. Then the oxygen of the air, carried by the blood to every part of the body, seizes on the resulting substances and bums them, more or less rapidly, producing a large quantity of heat to replace that which the body is constantly losing by radiation and otherwise, while the products of this burning are finally excreted from the body. The body is thus continually suffering a loss of material. To replace this loss, as well as to supply material for fur- ther growth, is the office of the food, which may, from this point of view, be regarded as a vehicle for the intro- duction of supplies of force into the body. It is the object of such a book as the present one to show how much and what kind of food is needed to sup- ply the losses arising under the various conditions to which farm animals are subject. In order to do this intelligently, we need to consider : ji/rst, the nature and extent of the processes going on in the body ; second, the materials avail- able as food ; and thirds the adaptation of these materials to the various purposes of feeding. The subject, then, naturally divides itseK into three parts : MANUAL OP OATTLE-rEEDING, 3 I. The General La-nrs of Animal Nutrition, or that portion of animal physiology which treats of the so-called " vegetative functions." This includes the composition of the animal body, the processes of digestion, circulation and respiration, and the production of flesh, fat, and work. n. The Coiaposition and Digestibility of Feeding- StaSk. m. The Feeding of Farm Animals — a consideration of the kind and quantity of food required for the various purposes for which such animals are kept. PAET I. THE GENERAL LAWS OF ANIMAL NUTRITION, CHAPTEE I. THE COMPpSITION OP THE ANIMAL BODY. § 1. Pbofortioks or tHB Diffbbbnt Oroans and Parts. The Fluids circulating in the blood and lymph vessels constitute but a small part, at most not more than Y to 9 per cent., of the live ^eight, and in old or very fat animals the proportion sinks as low as from 4 to 6 per cent. The digestive fluids and other secretions and fluid excretions, although they are produced in considerable quantity in the course of twenty-four hours, can hardly be taken into account as constituents of the body, since they are being produced at every instant, are formed more or less directly from the blood, and are partly re-absorbed into it or pass out of the body ; while the blood, on the other hand, al- though continually giving up material to the tissues and receiving new from the food, remains very constant in its quantity and chemical properties. The Solid Tissues. — The fresh bones constitute, ac- cording to the kind, age, and condition of the animal, 6 to 12 per cent, of its weight, the muscles and tendons 35 to 48 per 6 MANUAL OF CATTLE-FEEDING. cent., and the fat, so far as it can be mechanically separa- ted, 10 to 40 per cent. It is to be noted, however, that the fresh bones contain 11 to 14 per cent, of water, and the muscles from 60 to over 75 per cent. The average of the results of numerous investigations made on the various farm animals gives them approximately the following composition : Bones 9 per cent. Flesh and tendons 40 " Mechanically sepaiable fat. 34 " The remaining 27 per cent, comprises the blood, hide and hair, entrails, and the contents of stomach and intestines. Fuller details regarding the proportions of the various parts in lean and fat animals of various kinds are to be found in the Appendix. It should be added that the volimie and weight of the contents of the stomach and intestines are very various, according to whether the animal has received a more or less bulky fodder. For example, in some investigations made by E. v. Wolff, in Hohenheim, with sheep, the fol- lowing averages were obtained : No. of Experiments. Fodder. Average live weight per head. Poands. Contents of stomach and intestines. Pounds. Contents in per cent, of live weight. 3* Chiefly straw 93.8 100.1 134.2 20.9 16.0 11.2 22 3 2* Hay, with small amount of beans 15 9 6t Clover hay, potatoes, peas, and com 9.04 * "Die Versuohs-Station Hohenheim," 1866-1870, p. 62. f Landvr. Jahrbiicher, I., 569. MANUAL OF CATTLE-FEEDING. Grouven * f oimd in the case of oxen : No. ot Ezperimenta. Fodder. Live weight. Founds. Contents ot stomach and intestines. Pounds. Contents In per cent, of live weight. 4 Straw 1,199 1,419 199 133 16.6 7 Fattening fodder 9.4 Fatted hogs give a less proportion, viz., 4 to 6 per cent. Lawes and Gilbert f, in fifty-niae experiments, found the proportion of stomach and intestines, together with their contents, to range from 5.59 per cent, to 10.13 per cent, of the live weight, the average being 7.52 per cent. § 3. Thb Non-Niteogbnotjs Constitdbhts op the Asimai. Body. Water. — One of the most important constituents of the animal body is water. This sijj)stance constitutes, under most circumstances, more than half of the entire weight of the animal ; it is contained in all parts of the body, and forms as essential an ingredient of the so-caUed solid tissues as do any of their other components. In the new-bom animal, water constitutes 80 to 85 per cent, of the total weight, but during the period of rapid growth the proportion of dry matter increases and that of water diminishes, so that the mature, but not fattened, animal may contain 50 to 60 per cent, of water. In the process of fattening, the percentage of water decreases * Zweiter Salzmunde Bericht, 1864, p. 137^ and Erster Bericht, p. 260. t Jour. Boy. Ag. Soc., Series L, XXI., 449. 8 MANUAL OF CATTLE-FEEDING. stili more, falling, according to the experiments of Lawes and Gilbert, below 50 per cent., and in one case (a very fat sheep) to 35.2 per cent, of the whole animal, or 33 per cent, of the dressed carcass. It is sometimes stated that, in fattening, the body loses water, its place being taken by nitrogenous matters and especially by fat, but the author has not been able to find any account of experiments which substantiate this view. Fat animals, it is true, contain a smaller percentage of water and a larger percentage of fat than lean ones, but this is not sufficient to prove the point, for an increase in the ahsolute amount of fat contained ia an animal would cause a decrease in the relative ampunt (percentage) of all the other ingredients, water included. The only method by which the truth of the above view can be determined, is to compare the absolute weight of water, fat, albuminoids, etc.,. in lean and fat animals of the same breed and as nearly alike as possible. Such comparisons have been made by Lawes and Gil- bert,* ia the following manner. Ten animals<©f different kinds, and in different stages of fatness, were slaughtered, and the percentages of ash, albuminoids, fat, and wa,ter in the whole animal determined, and by this means data were- obtained for estimating the absolute amounts of these sub- stances in the body of a living animal whose weight was known. A large number of animals were then fattened, and, their composition before and after being estimated as above, it was easy to determine the amount of each in- gredient which had been produced, and from this the per- centage composition of the increase in weight. * Jour. Eoy. Agr, Soc, Series I., XXI., 456. MANUAL OF CATTLE-FEEDING. 9 The following table shows the average results for oxen, sheep, and hogs : Average Composition, of the Increase of Live Weight in Fattening. ABh. Per cent. Protein. Per cent. Fat. Percent. Total dry matter. Per cent. Water; Per cent. 98 Oxen. . 348 Sheep. 80 Hogs. . Average 1.47 2.34* 0.06 1 7.69 7.13 6.44 66.3 70.4 71.5 1.10 7.26 67.8 75.4 79.9 78.0 24.6 20.1 22.0 76.2 23.8 It is evident from the method followed that the results are not absolutely accurate, but they suffice to show that in fattening, a gam, of water takes place, though it is rela- tively small. The same conclusion is indicated by recent experiments by Henneberg, Kern, and Wattenberg,:j: on the fattening of sheep. They slaughtered animals in two stages of fattening, and also, at the beginning of the experiment, others which had not been fattened. The following numbers, taken from their results, show the total gain of weight by the " fat " and the " very fat " animals, and also the excess of fat and flesh contained in their bodies over that found in the unf atted ones : * Probably too high, owing to dirt in the wool, f Probably too low. I Biedermann's Gentral-Blatt., Jahrg. 8, p. 262. 1* 10 MANUAL OP CATTLE-FEEDING. Lean. PoundB. Fat. Fonndfl. Very fat. Fonnds. Original weight 90.53 90.53 89.54 116.45 26.91 89.10 Final weight 128.86 Gain 34.76 Gain of fat 24.51 —0.33 33.78 Gain of flesh 0.51 Total, fat ftTirl flesh 23.18 3429 The increase of fat and flesh is, in each case, less than the total gain, showing that there was a gain of some- thing else, and making it improbable that any essential loss of water took place, especially as the flesh was found to contain almost exactly the same percentage of water in the very fat and in the lean animals, viz. : Lean 79.41 per cent. ' Veryfat 79.03 Unfortunately, however, no such complete analyses of the whole animal were made in these trials as in those of Lawes and Gilbert, and hence the data which they afford are insufficient to settle the question. The dry substance of the animal body consists of organic and inorganic matter, ^and the former, again, of nitrogenous and non-nitrogenous materials. By organic matter, in the above sense, is miderstood matter which is combustible, and which, when subjected to the action of fire, disappears, leaving the inorgcmic mat- ter behind as ashes. The terms are not strictly correct, since the ash of a MANUAL OF CATTLE-FEEDING, 11 piece of flesh, or of a mass of wood, was as really organ' ized, and formed as truly a part of it, as the so-called or- gcmio portion, but they are in common use with this meaning. The organic matters of the animal body are classified, according to whether they contaia the element nitrogen or not, as nitrogenous or non-nitrogenous. Pat. — Of the non-nitrogenous substances fat is by far the most abundant. It is present in the blood in minute quantities, generally constituting not more than 0.1 to 0.3 per cent, of it; it exists in larger ^^^^^ quantity in the substance of the ^^^ij^P^^b nerves and in the bones, but is chief- /^^^M^^fe ly found enclosed in special cells or ^S^^^^^^^^ tissues under the skin, on the kid- \^^^^^0^^^^ neys, omentum, and mesentery, and l^^^^j^^^^ in the flesh between the bundles of ^^^'^^^^ muscular fibres., Fio. i.-(Settegast). Fat- The thin membrane which com- '^^' poses the cell-walls of the fat-tissue is a nitrogenous sub- stance, and constitutes only 0.8 per cent, of the whole tissue when the latter is entirely filled with fat, but when this is not the case its amount may rise to 4 per cent., or over. The quantity of water in the fresh fat-tissue stands in a fixed relation to the amount of membrane (about 5 or 6 to 1), so that the quantity of water may vary from 4 to over 24 per cent., according to whether the cells are more or less laden with fat. Most of the fat-cells of the living body contain liquid, perfectly transparent fat, but its consistency varies in the different organs ; it solidifies to a solid, butter-like mass more or less easily, according to whether the oily or the solid fats predominate. The appearance, also, as well as the 13 MANUAL OF CATTLE-FEEDING. Bmell and taste, of fat taken from different kinds of animals, or from different parts of tlie same animal, is very variable, on account of admixtures of small quantities of coloring matters and volatile substances of all sorts ; but this has almost no influence upon the elementary composi- tion of the fat, which is very constant. Schulze andEeinecke,*attheWeende Experiment Sta- tion, found twenty-eight samples of mutton, beef, and pork fat, taken from different individuals and from different parts of the body, and freed from the fat-membrane and from water, to have the following composition : Cabboh. Htoboqbk. OZYOSK. Av. Per cent. Max. Per cent. Min. Per cent. Av. Per cent. Per cent. Min. Per cent. Av. Per cent. 11.59 11.52 11.86 Max. Per cent. Min. Per cent. Beef fat.. Pork fat 10 6 12 76.50 76.64 76.61 76.74 76.78 76.85 76.27 76.29 76.27 11.91 11.94 12.03 12.11 12.07 12.16 11.76 11.86 11.87 11.86 11.83 11.56' 11.16 11.15 Mutton tat 11.00 Average of all the An- Blyees in round numbers. 76.50 12.00 11.50 Other results were : Fat from Carbon— per cent. Hydrogen— per cent Oxygen— per cent. Dog 76.63 76.56 77.07 76.62 12.05 11.90 11.69 11.94 1132 Cat 11.44 Eoxse TVTftn. 11.34 1144 * VersuohB-Stationen, IX, 97. MANUAL OF CATTLE-FEEDING. 13 It is evident from these figures that ia all calculations regarding the gain or loss of fat by the body, we may treat this fat, in spite of the numerous modifications which it undergoes in the various organs, as chemically identical, without falling into any appreciable error. The quantity of fat which may be laid up in the body is often enormous. For example, in the case of fattened neat-cattle and swine, the fat may make up from 25 to over 40 per cent, of the live weight of these animals, or from two to three times as much as aU the nitrogenous substances present. In lean animals, on the other hand, the amoimt of fat is much less, and that of the nitror genous substances relatively greater. Other Non-Nitrogenous Organic Substances. — ^AJl the non-nitrogenous organic substances, other than fat, which occur in the body, and are to be regarded as normal constituents of it, are very inconsiderable in quantity, al- though often of importance for the functions of the organs or fiuids in which they are found. The gastric juice (the digestive fluid of the stomach), and also the contents of the 'large and small intestines, and sometimes the chyle of the thoracic duct (see p. 68), con- tain tacbio add, the well-known acid of sour milk, while the juices of the flesh contain another acid — sm'kolactia add — isomeric* with the former. The blood, and in fact almost aU the animal fluids, also contain minute quantities of one or the other of these acids. Sugar is likewise found in ,the blood, but at most in quantities not exceeding 0.015 per cent., except in the * Two BubHtances aie said to be isomeric when they have the sama percentage composition, but different chemical properties. 14 MANUAL OF CATTLE-FEEDING. blood of the hepatic vein (the vein leading from the liver toward the heart), where the amount rises to about 0.1 per cent. The liver itself contains a considerable quantity of a sub- stance called glycogen, somewhat resembling starch, which is continually yielding sugar by its decomposition. The sugar iu the hepatic vein has its source in the glycogen of the liver. The muscles likewise contain glycogen, and also small quantities of a non-nitrogenous substance peculiar to themselves, and resembling sugar in composition and properties, called i/nosite. Furthermore, various non-nitrogenous organic com- pounds occur in the bile, and innumerable such in the so- called extractive matters of the tissues and juices, that is in the mixture of substances obtained by treating the flesh, etc., with alcohol. The " extractive matters " give to meat soup its agreeable taste and smell. The weight of all these substances, however, is inconsiderable, and van- ishes almost entirely in comparison with the great quanti- ties of fat and nitrogenous matter in the whole body. § 3. NlTROGBNOTTS ORGANIC SXIBSTANCES. Of the nitrogenous constituents of the body, there are three principal groups to be considered, viz., the Albu- MiNoros, Gblatigekous Substances, and Hoent Mattees. The albuminoids are by far the most important of the three, since all manifestations of animal life are dependent chiefly on them and the organs which are composed of them, and since they furnish the material out of which the members of both the other groups are formed ; while the latter, once formed, do not appear to be capable of MANUAL OF CATTLE-FEEDING. 15 being altered back into albuminoids, or of performing tbe functions of the latter in nourishing the body. Albuminoids. — The albuminoids are found in manifold modifications in all the organs and fluids of the healthy body, except the urine, and all these modification^ suffer an almost continual mutual alteration under the influence of the \dtal processes. Notwithstanding their diversity, however, they have many and marked characteristics in common. As their name implies (albumiaoid — albumin-like), they resemble albumin or white of egg. Like it, they are des- titute of any crystalline form (amorphous). Most of them exist in at least two modifications — a soluble and an in- soluble one. In the soluble form they constitute, when dried at a gentle heat, transparent, white or yellowish solids, destitute of taste or smell, and soluble in water ; in the insoluble modification they form white, flocculent or fibrous masses, insoluble in water, and, like the soluble forms, having neither taste nor smell. The soluble albuminoids are very readily converted into the insoluble form by a variety of means ; in some cases by heat, in others by the action of acids or other bodies, and in still others from some cause not yet known. This change is called coagulation; it is apparently only a change in the condition and not in the nature of the substance. At any rate, it is not accompanied by any change in composition. Almost innumerable varieties of albuminoids have been described, and much confusion exists as to their properties, and relations to each other. For our present purpose, however, it will suffice to indicate, the three groups into which these bodies may be classified — ^viz. : Albumin (represented by white of egg), Fihrin (repre- sented by lean meat), and Casern (the basis of cheese). 16 MANUAL OF CATTLE-FEEDING. , Albumin predominates in all animal fluids, especially in the so-called chyle, in the colorless serum (see below) of the blood, and in the fluid contents of the blood-corpus- cles, where it is tinted red by the coloring matter of the blood. It also occurs in the juice of the muscles and in the nerves. It is distinguished by the property of coagulating when heated above a certain point. For pure albumin this point is 165° F. ; for solutions of albumin it is higher in proportion as they are more dilute. (A good example of coagulation is furnished in the boil- ing of an egg. As the heat of the boiKng water penetrates the egg the albumin changes from a transparent soluble liquid to an opaque solid which no longer dissolves in water.) Fibrin. — The" blood of all the higher animals, shortly after it is removed from the body, partially solidifles, and separates into two parts, the " clot " and a yellowish liquid called the serum. The serum contains albumin and the dissolved matters of the blood generally ; the clot contains an albuminoid known as Uood-fibrin, colored red by the blood-corpuscles which it has entangled within itself while coagulating. Authorities differ as to the nature of this so-called spontaneous coagulation, and for our present purpose it is not necessary to enter upon the subject. When purified, as far as possible, from adhering im- purities, blood-fibrin is a white, fibrous-looking, elastic substance, in which the microscope shows no traces of any structure, fibrous or otherwise. FUsh-jibrin, the chief constituent of aU muscular fibres, differs from blood-fibrin in the fact that it appears in or- ganized structures in the form of variously shaped and MANUAL OP CATTLE-FEEDINO. 17 grouped cells. Flesh-fibrin behaves, also, somewhat differ- eutly to chemical reagents from the coagulated blood-fibrin, but, like all insoluble modifications, it is easily converted by the action of the digestive fiuids into a soluble form. Casein is found in considerable quantity only in milk ; it is a product of the milk-glands and therefore not to be looked upon as a constituent of the body in general. It does not coagulate on heating ; the tenacious skin which forms on the surface of milk when it evaporates is a sub- stance altered by the action of the air. On the other hand, the casein separates almost com- pletely in a coagulated state when a small quantity of rennet is added to the milk, as in making cheese, or when the milk is gently warmed with dilute acids or various other substances, as well as in the natural somiig of milk. Composition. — ^All the albuminoids contain, as essen- tial constituents, carbon, hydrogen, oxygen, nitrogen, and sulphur; and these constituents are present in such con- stant quantities that it is impossible to distinguish the various albuminoids from each other by their percentage composition, samples of the same albuminoid from different sources often showing as great differences as exist between members of different groups. The following numbers show the extremes of variation : Carbon 53-54 per cent. Hydrogen 7 " " Nitrogen 15-17 " " Oxygen 34-31 " " Snlphnr 1-1.5 " " Generally the average amount of nitrogen is assumed to be 16 per cent., and the total quantity of albuminoids in a 18 MANUAL OF CATTLE-FEEDING. substance is calciilated by multiplying the percentage of nitrogen found by analysis by 6.25 (6.25 x 16=100). The phosphorus which always accompanies the albu- minoids seems to be held only loosely as phosphoric acid, and not to be an essential ingredient of them. Gelatigenous Substances. — The gelatigenous substances constitute scarcely less of the weight of the body than the albuminoids. They form the nitrogenous organic substance of bone and cartilage, and make up the larger part of the mass of the tendons, ligaments, and connective tissue, and of the skin. By protracted boiling with water the gelatigenous substances are completely dissolved, and converted into glue. Their composition is very similar to that of the albuminoids, except that they generally contain somewhat less carbon (50 to 51 per cent.), and in case of cartilage also less nitrogen (about 15 per cent.), while the gelatigenous substance of the bones, tendons, and skin, on the contrary, is richer in nitrogen (about 18 per cent.). The sulphur is also either entirely lacking, or is present in smaller quan- tity than in the albuminoids. HoENT Mattees. — The homy matters are found chiefly on the outer surface of the body, either in a thin layer, as the epidermis (scarf-skin), or in well-characterized tissues, as hair, wool, horns, nails, hoofs, claws, feathers, etc. The average composition of all these tissues is very uniform : Carbon SO-51 per cent. Hydrogen about 7 " Nitrogen 16-17 " Oxygen 22-20 " Sulphur 3-5 " In the main, therefore, they differ from the albuminoids MAKtrAL OF CATTLE-PEEDIITG. 19 and gelatigenoTis substances only in containing more sul- phur, while the proportions of the remaining constituents are almost the same. Average CoMPOsmoN. — It will be seen that all the important nitrogenous substances which occur in the body are very similar and, on the average, almost identical in composition with the pure albmninoids out of which they were all formed, directly or indirectly, in the processes of nutrition and growth. This agreement was also found in the investigations of Lawes and Gilbert on whole bodies of animals, already re- ferred to. In these experiments the total quantity of water, fixed mineral matters, fat, and organic substances other than fat was determined, and the nitrogen of the latter was estimated. The amount of " organic substances other than fat " foimd directly, agreed almost exactly with that obtained by midtiplying the quantity of nitrogen found by the usual factor, 6.25 ; in other words, all the organic sub- stances other than fat were found to contaiu, on the aver- age, almost exactly 16 per cent, of nitrogen. In the average of all the experiments, the organic matter other than fat was found to be 14.67 per cent, of the dressed weight, and the amount of albuminoids calculated from the nitrogen, 14.83 per cent. This shows at once that all the nitrogenous organic matters of the body aside from the three groups already mentioned, e. g., certain constituents of the bile, of the juice of the muscles, etc., have, on ac- count of their relatively small quantity, no material influ- ence on the elementary composition of the organic sub- stance of the body, and especially none on the percentage of nitrogen. 20 MANUAL OF CATTLE-FEEDING. § 4. Inokganic, or Non- volatile Matters. Amount. — The total quantity of the inorganic portion, or ash, of the animal body is, in round numbers. In neat cattle 4-5 per cent, of the live weight. "sheep 2.8-3.5 " " " "swine 1.8-3.0 " " " In lean animals the amount approaches the maximum, in fat animals the minimum. Phosphoric acid and lime are present in about equal proportions and make up together about four-fifths of the total quantity of ash, while the other fifth consists of potash, soda, magnesia, chlorine, sulphuric acid, carbonic acid, and, to a very minute extent, of silica. The sulphur, mentioned above as forming part of all the important nitrogenous substances of the body, is not included in the ash. In the bones, as is weU-known, the quantity of mineral matter (bone-ash) is especially great, and amounts, on the average, in a full-grown animal, to about two-thirds of the dry, fat-free substance of the bones. Immediately after birth, the dried bones contain only about 50 per cent., and in advanced age often as much as Y5 per cent, of ash. The outer and more solid layers are always richer in ash than the inner and porous parts, es- pecially in the hollow bones. At least seven-eighths of the total bone-ash is phosphate of lime, the remainder is car- bonate of lime- with small quantities of magnesia, fluorine, and soda. Besides phosphoric acid and lime, the most important inorganic constituents of the body are potash, soda, and chlorine (the two latter generally combined to form chlo- ride of sodium or common salt). Need of a Continual Supply. — The quantity of these MANTTAL OF CATTLE-FEEDING. 21 substances in the various tissues and fluids, while it is very constant, is relatively small, except in the case of the bones, but they are absolutely essential constituents of all those parts of the body in which the vital processes are most actively carried on, and in which, consequently, de composition and rebuilding* are continually taking place. As a consequence, they are continually excreted from the body in considerable quantities with the final products of the metamorphosis of tissue, and the vital processes would soon suffer important disturbances were not a continual, almost daily, supply provided. Salt-hunger. — ^Numerous experiments have shown that when animals are fed on food from which the mineral matters (salts) have been extracted as completely as pos- sible, they become sleepy, weak, especially in the extremi- ties, and finally die from lack of mineral food, although the quantity of organic food eaten and digested may be amply sufficient to sustain life. As an example of these may be mentioned some experi- ments made at the Physiological Institute of the Univer- sity of Munich, by Forster,* on pigeons and dogs. The pigeons were fed with starch and casein, made as free from ash as possible ; the dogs with meat repeatedly extracted with water (to remove the mineral matters) and with fat, sometimes with addition of starch. The results were the same in every case. AH the animals became,' after a few days, in consequence of " salt-hunger," dull and inactive ; a rapidly increasing weakness of the muscles ap- peared, particularly in the extremities, and toward the end of the experiment cramps and shivering showed a great imtability of the nervous system. *Zeit8ohr. f. Biologie, IX., 297. 22 MANUAL OP CATTLE-FEEDING. The digestion, however, as well as the utilization of the digested nutrients, was exactly the same as under normal conditions, and the animals, when killed at the end of the experiments, were found to be apparently well nourished, and with all the organs in a healthy state. We must conclude from these, and numerous other simi- lar researches, that the phenomena of dulness and weak- ness observed in all such experiments are due directly and exclusively to the lack of inorganic ingredients in the food, and that the comparatively speedy death is caused by 'the separation from the animal organs and juices of those salts necessary for the due performance of their functions, and their removal from the body in the urine. Essential and Accidental Salts, — The greater por- tion of the inorganic matters of the body exists, in com- bination with organic substances, as an essential constitu- ent of the various tissues and juices. Strictly speaking, it forms part of the organic (or organized) portion of the body. Its amount is very constant. Another variable and much smaller portion, which we may call accidental, exists simply dissolved in the fluids of the body, without really forming part of it. This portion can never be very great, even with an abundant supply of salts in the food, since the latter are rapidly excreted in the urine, and the more rapidly the greater their quantity ; while those salts which enter into the composition of the tissues can be ex- creted no faster than they are set at liberty by the using up of the tissue, and, in fact, even when thus set at liberty, may recombine, in part, with organic matter to form new tissue. This latter fact is particularly noticeable when the food is poor in salts. Thus, it was found in the experiments already described (p. 21) that the excretion of salts was MANITAL OF OATTLE-FEEDING. 23 least when the food was most abundant but was poorest in salts, showing that nature can be very economical and get on with a minimum. There is a limit to this, however. The excretion of salts can be diminished but not entirely pre- vented, and if the supply of salts is too small, the animal loses mineral matter continually, and sooner or later dies. Practical Conclusions. — ^In practice, in the feeding of mature animals intended to be kept in a medium condition, or to be fattened, a lack of the necessary mineral matters is scarcely ever to be feared. They are, indeed, generally present in large excess. Only common salt is in certain respects an exception, as will be explained more fully below. The opinion is indeed somewhat prevalent that a lack of phosphate of lime in the fodder may be the immediate cause of the disease, prevalent among cattle in some neighborhoods, called rickets. This explanation is, however, at most, only vahd in case this lack was experienced by the animal from its earliest youth up. In the case of full-grovm and healthy animals, the lack of phosphate of lime cannot well be the cause of the disease, since experiment has shown that such animals, when they are insufficiently supplied with this substance, dio in a comparatively short time, and before any essential change takes place in the composition of the bones. Young and rapidly-growing animals naturally need, both relatively and absolutely, a greater quantity of phosphate of lime than old and full grown ones. In the feeding of milk cows, too, regard must be had to the quantity of phosphate of lime in the fodder. (See Part III., chapters Y. and VI.) Uses of Common Salt. — As mentioned above, salt occupies, to a certain extent, an exceptional position. 24 MANUAL OF CATTLE-FEEDING. Besides its strictly physiological functions, it is of use in facilitating the passage of the albuminoids of the food from the digestive canal into the blood, and to a certain extent in facilitating the circulation and thus increasing the energy of the vital processes. For this purpose a certain excess of salt seems to be necessary, which circulates rapidly through the body, and is excreted in the urine in quantity corresponding to the amount taken. This need of salt is especially manifest in certain kinds of herbivora, and particularly in such as, like our domestic animals, are largely stall-fed and, by means of abundant fodder, are caused to produce largely either flesh and fat, nulk, or work. To this may be added that many fodders in common use, such as potatoes, roots, grains, etc., are comparatively poor in sodium chloride and rich in potash salts, which latter, it has been found, cause an increased excretion of salt through the urine. In view, then, of the absolute demand for a certain amount of salt for the preservation of life and the great advantages of a certain excess of it, it is plain that it is to be regarded not as a luxury but as a necessity. CHAPTEE n. COMPONENTS OP FODDERS.— NUTEIBNTS. I 1. DEFiNrnoNS. Nutrient, Fodder, Ration. — ^In the preceding chapter we have seen that the animal body, in spite of the great complexity of its structure, may be considered, in a general way, as composed of nitrogenous and non-nitrogenous or- ganic substances, and of mineral matters. Since, now, these substances are being constantly de- stroyed in the body in the performance of the vital func- tions, it is necessary that the animal should receive from without a supply of substances identical with or similar to those destroyed, and which can be assimilated by the tis- sues and fluids of the body to replace those lost and enable the vital actions to continue. Any single chemical compound, such as albumin, fat, starch, sugar, etc., which is capable of aiding to replace this loss is called a nutrient. Such substances do not occur in a pure, unmixed state in nature, but are found in various forms and proportions in aU fodders. By a fodder, or feeding-stuff, we imderstand any natu- ral or artificial product which is used as food for animals ; e. g., hay, oil cake, roots. Since the animal organism not only contains various nitrogenous and non-nitrogenous substances, but contains them in proportions varying only within narrow limits ; and sinciB the rate at which each is destroyed in the body a 26 MANtTAL OF CATTLE-FEEDING, is also fixed within certain Kmits ; it is plain that the food which the animal receives must also contain the varioua nitrogenous and non-nitrogenous nutrients in proper pro- portions. K fodder usually contains several or all of the groups of nutrients., but may not contain them in the proper pro- portions to satisfy the needs of the organism. Thus, in the examples given above, good hay contains aU the groups of nutrients in proper proportions, and will sus- tain an herbivorous animal indefinitely ; while oil cake and roots contain an excess, the one of albuminoids, the other of bodies of the starch or pectin groups, and so, if capable of sustaining life, do it with a great waste of the one or the other material. They are one-sided foods. By combining several one-sided foods, we may prepare a mixture which shall contain all the groups of nutrients in proper proportions and be capable of sustaining an animal economically. Such a mixture we may call a ra- tion or a complete food. The proportions of the various nutrients in the common fodders and the proper combining of fodders to form ra- tions suitable for vai-ious purposes will be treated of iti Parts II. and III., and we shall concern ourselves here only with the occurrence and properties of the nutrients. These it is necessary to consider in order to a proper un- derstanding of the processes of digestion and assimilation. The nutrients are divided into three groups, corresponding to the three groups of substances in the animal body, viz. : nitrogenous, non-nitrogenous, and mineral substances. § 3. Nitrogenous NuTurENTs.' Peotein. — The predominant nitrogenous constituents of plants resemble closely, in all important particulars MANUAL OF OATTLE-FEEDING. 27 the albuminoids of the animal body, and have, like them, been called albuminoids or protein bodies. The name jprotein was used by Mulder to designate a supposed substance which formed the basis of all the albuminoids. The word is no longer used in this sense, but is very commonly met with as a collective term for all the albuminoids, and we shall thus use it in the present work. The vegetable albuminoids which have as yet been in- vestigated may be divided into three groups, albumin, casern, and Jibrin, having more or less resemblance to the corresponding groups of animal albuminoids, though it is doubtful if the two are identical. Vegetable Albumin appears to occur chiefly in the, young and growing parts of plants, while in the older parts it is converted into other forms of protein. It is contained, dissolved in small quantities, in the sap of fresh plants, and coagulates when the sap is heated. Tegetable albumin is soluble in cold water, in dilute potash solu- tion, and in dilute acetic acid ; it is insoluble in alcohol, and is very similar in all its properties to animal albumin. Its composition varieE somewhat according to the source from which it is derived. The fol- lowing table shows the extremes of variation : Animal albumin (av.). Per cent Vegetable albumin. Fer cent. Carbon. .. Hydrogen Nitrogen . Oxygen . . Sulphur. . S3. 5 7.0 15.5 2S.4 1.6 52.3-54.3 7.1- 7.7 15.5-17.6 20.6-23.0 0.8- 1.6 The composition of animal albumin is not far from the average for vegetable albumin, but the identity of 'the two is, at best, doubtful. 28 MANUAL OF CATTLE-FEEDING. Vegetable Casein. — If wheat flour be made into dough, and the dough kneaded in a stream of water, the starch of the flour is washed out, and a sticky mass remains, known as crude wheat-gluten. The crude gluten thus obtained is a mixture of at least four albuminoids, and contains, besides, some starch and fat. When treated with dUute (60 to 80 per cent.) alcohol at ordinary temperatures, three of these albuminoids are dissolved, while the fourth, called ghtten-casein, re- mains behind, together with various " impyrities. The same or a very similar substance is also contained in rye, barley, and perhaps in buckwheat, and in the " oil seeds ; " while oats contain an albimiiaoid having some of the prop- erties of gluten-casein but more closely resembling the legumin about to be described. In addition to gluten-casern,, two other bodies belonging to the casein group have been described, viz. : iegumvn, the chief albuminoid of the seeds of the legumes (peas, beans, etc.), and conglutm, contained in almonds and in maize (?) The properties of these albuminoids, and in particular those of legu- min, resemble very closely those of animal casein. Legumin is in- soluble in water. It is, however, quite soluble in water containing small quantities of basic phosphates, especially of potash, and hence warm water extracts legumin from the seeds of the legumes, since the latter contain soluble phosphates. Such a solution of legumin is not coagulated by heat, but is by acids, and according to one authority by rennet. Legumin is insoluble in either strong or dilute alcohol, but very readily soluble in dilute potash solution, and somewhat soluble in dilute acids. The reactions of gluten-casein, as well as those of con- glutin, are very similar to those of legumin. The composition of these albuminoids, like that of all others, varies more or less according to their source and MANUAL OP CATTLE-FEEDIira. 29 mode of preparation, owing largely to the great difficult j of obtaining them in a pure state and in part perhaps, to the non-identity of substances bearing the same name but derived from different sources. The following table shows some of Eitthausen's results.* Olnten-oBsein. Per cent. Lkoumin fbou Data. Per cent. Peas. Per cent Beans. Per cent. Maize. Per cent. Sweet almonds. Per cent. rJurban '52.70-5.3.16 6.95- 7.15 16.70-17.21 21.92-22.18 0.9.3- 1.27 51.63 7.49 17.45 22.64 0.79 61.48 7.02 17.13 23.97 0.40 61.48 6.96 14.76(5) 26.35 0.45 51.41 7.19 17.72 i 23.68 60.44 Iff 6.85 16.61 23.67 Sulphur. 0.43 Vegetable Fibrin.— When crude wheat gluten is treated ^ith alcohol in the preparation of gluten-casein, as above described, a solution is obtained from which an albuminoid known as gluten-fhrm, inay be prepared as a tenacious, translucent substance of a brownish-yellow color. It is insoluble in water or absolute alnohol ; soluble in dilute alcohol, In dilute acids, and in dilute potash solution. When heated, it is con- verted into an insoluble modification, which is not dissolved by dilute acids or alkalies. The same or a similar substance is contained in barley and maize. The composition of vegetable fibrin, like that of the other albuminoids, varies more or less. Kitthausen ob- tained the following results : * Die Eiweisskorper der Cretreidearten, etc. , 1873, and Jahresber. Agr. C!hem., N. P., I., 168. 30 MANUAL OF CATTLE-FEEDING. Carbon. . . Hydrogen Nitrogen,. Oxygen... Sulphur. . From wheat. Per cent. 54.31 7.18 16.89 20.61 1.01 100.00 From barley. Per cent. 54.55 7.27 15.70 22.48 100.00 From maize. Per cent. 64.69 7.51 16.33 20.78 0.69 100.00 Mucedin and Gliadin. — Besides gluten-casein and glu- ten-fibrin, wheat gluten contains two other albuminoids, viz. : mucedin, and gliadin or vegetable glue. Mucedin, when freshly prepared and containing water, is a yellowish- white, slimy substance, somewhat translucent and with a silky lustre. It is soluble in dilute alcohol, but insoluble in strong alcohol, which precipitates it from its solutions. Its behavior to water is peculiar. It is scarcely soluble, but when agitated with water, can be suspended in it, forming a turbid, slimy fluid, which, on long standing, deposits the mucedin unaltered. The same results are obtained if the water is warmed instead of stirred. Continued boiling with water decomposes mucedin, and alters most of it into an insoluble substance. G-liadin very closely resembles animal glue in its properties. It is soluble in both weak and strong alcohol, in alkalies, and in acids. In cold water it swells up like glae ; prolonged boiling with water decomposes it. The com/position of mucedin and gliadin obtained from wheat was found by Ritthausen to be : Carbon... Hydrogen Nitrogen. Oxygen. . . Sulphur . . Gliadin — ^Per cent. 52.67 7.10 18.0i 21.37 0.85 MANUAL OF OATTLE-FEEDIirG. 31 Mncedin is also found in rye and barley, and gliadin in oats. Other Albuminoids. — It wiU not have escaped notice that in the above paragraphs we have confined ourselves chiefly to a consideration of the albuminoids of the cereal grains and the legumes. This is simply because these are the only vegetable prod- ucts which have been investigated with any degree of completeness. Doubtless other feeding-stuffs would be found to contain still other varieties of protein, were they investigated, but at present we know little or nothing re- garding them. Comparative Value in Nutrition. — ^While the vari- ous albuminoids of the vegetable world vary not inconsid- erably in their composition, especially as regards carbon and nitrogen, they still show such strong general resem- blances, both in composition and properties, to each other and to the animal albuminoids, that we must consider them all as closely related bodies. Indeed they seem capable, to a certain extent, of conversion into each other in various ways. Whether the various vegetable albuminoids are equally valuable as nutrients, are assimilated and formed into part of the body with equal ease, we are unable to say, owing to the entire lack of experiments on the subject. It is, perhaps, questionable if they are, but the differences, if they exist, are probably not great, and for the present we must consider them all as equivalent, so far as they are actually digested. The recent experiments of Wildt * and of E. v. Wolff f on swine seem also to show that the animal albuminoids con- • Landw. Jahtbuchar, VI., 177^ f Ibid., VIII., 233. 32 MANUAL OF CATTLE-FEEDING. tained in dried blood and flesh-meal (the residue from the preparation of "Extract of meat,") are equivalent in nutri- tive effect to vegetable albmninoids. It is possible that we ought to regard gliadui as formmg an exception to the equivalence of the albuminoids on ac- count of its great likeness to animal glue, or gelatin, the latter havmg been shown by Voit* to be incapable of per- forming all the functions of protein in the food. Importance. — This close mutual relation and easy con- vertibility of the albuminoids has the highest significance for animal nutrition. As we have seen,'the most important solid components of the animal body are the albuminoids and related bodies. It is these which constitute its muscles, tendons, nerves, in fact all its working machinery. Now, so far as we know, the animal organism has no power to originate a particle of these substances. Its sole source of them is, in the herbivora directly and in the camivora indirectly, the albuminoids of the plant. These, by virtue of their great similarity to the animal al- buminoids, are readily altered into them and become part of the body. They are hence indispensable elements of any food, and likewise the most important, since, while they can, to a certain extent, take the pla,ce of the non- nitrogenous nutrients, none of the latter can possibly re- place the albuminoids; and they are of all the greater importance because, while the animal body is, to so large an extent, composed of them, they are found in compara- tively small quantity in most parts of plants. Evidently, then, the proportion of albuminoids which a fodder contains is an important element in determining its * Zeitschrif t f . Biologie, VIIL, 397. MANUAL OF OATTLE-FEEDING. 33 value ; and those fodders which contain them in the largest quantity are, other things being equal, the most vahiable, since the albuminoids are the most expensive ingredients to produce. Ooourrence in Plants. — This is not the place for a discussion of the composition of the various fodders, but a few general considerations regarding the distribution of the albuminoids in the plant may not be out of place. In the plant, as in the animal, life manifests itself chiefly through the albuminoids, and consequently all young and growing plants and parts of plants contain them abimdantly, while in the older portions, which have for the most part finished their growth, they are present in much smaller proportion, both owing to the increase of other substances, chiefly woody-fibre, and an actual transfer (translocation) of albuminoids to other parts of the plant. This is one reason of the greater nutritive value of young grass and green fodder in general, of hay cut while still young, etc. (See, however, page 299.) In mature plants the albuminoids tend to accumulate in the seeds. Thus the grains, beans, peas, etc., contain large quantities of albuminoids and owe to them, in a large meas- ure, their value as fodder, while the plants on which they grow, if allowed to stand till the seed is ripe, become cor- respondingly impoverished in these compounds. In the case of the cereals, it is the seeds which we desire, and hence we allow the plant to mature. On the other hand, in the case of the grasses, belonging to the same natural family {graminew), we use the whole plant as fodder, and hence cut it before the seed matures, because, although the whole amoimt of albuminoids is not decreased in ripening, it is largely stored up in the seeds, and these are mostly lost in the processes of curing, while 3* 34 MANTJAL OF CATTLE-FEEDIKG. such as are retained, owing to their small size, escape mas- tication and are not digested. The proportion of albuminoids in the same species of plants and in the same parts of the plant differs according to the quality of the soil on which it is grown, the manur- ing, the weather, and other circumstances, so that it is only by means of numerous analyses that the average composi- tion of any fodder can be ascertained. A discussion of these points and of the results of analyses of the more im- portant fodders will be found in Part 11. Othee Niteogenous CoNSTmjENTS OF Plants. — ^Vari- ous nitrogenous substances not belonging to the albumi- noid group have been found in plants. For our present purpose, we may divide them into four classes : 1. Nitrates, nitrites, and ammonia salts/ 2. Peptones; 3. AVcaMds; 4. Amines, amides, and amido-aeids. Nitrates, Nitrites, and Ammonia Salts. — These sub- stances usually occur very sparingly in plants, though beets, and probably other root crops, contain considerable quan- tities of them, and maize also frequently contains a not in- considerable amount of nitrates. These substances, how- ever, need hardly be taken into account here, since they have no nutritive value. Peptones. — ^Kecently, v. Gorup-Besanez has shown {B&)'. Deut. C/iem. Ges., 18Y4, p. 1478) that the seeds of the vetch contain a ferment capable of converting starch into sugar and albuminoids iato peptones,* and a similar substance has since been found in other seeds. It is highly probable that, • See p. 59. MANUAL OF CATTLE-FEEDINO. 35 during germination, these fei^ments act on the albtmiinoids of the seeds, converting them into peptones and so facilitat- ing their translocation into the young plant. How exten- sively or in what amount peptones are to be found in plants, we have no certain knowledge. Alkaloids. — ^The term alkaloid (alkali-like) is applied to a class of organic bodies possessing more or less marked alkaliae characters, a bitter taste, and poisonous or nar- cotic qualities. Morphine, strychnine, and nicotine, are common examples. These bodies, though quite widely distributed in the vegetable Idngdom, occur in few of our ordinary fodder plants, the principal one being ihe lupine. Siewert {Jahresber. f. Agr. Ohem., 13-15, 11. 6) found in the seeds of the yeUow lupine 0.6 per cent, of alkaloids, and in those of the blue lupine 0.63 per cent., and H. Schulze {Lamdw. Jahrbucher', YIIl., 37) obtained only 0.39 per cent. Amines, Amides, and Amido-acids. — By these names the chemist understands certain nitrogenous organic sub- stances, having a more or less close chemical resemblance to ammonia. When solid, they are generally crystalline and soluble in water, and pass easily through a moist membrane by the process of liquid diffusion, differing in these respects from the albuminoids, many of which are slightly or not at all soluble in water, and all of which are non-crystalline, and diffuse with extreme slowness. Most of tiiem, when boiled with dilute acids or alkalies, give off their nitrogen, wholly or in part, as ammonia. The first one to be discovered was asparagin (amido- succinamic acid) by Vauquelin and Kobinet in 1805, in asparagus shoots. The same body has since been found in a large number of plants or parts of plants, and appears to be quite widely distributed in the vegetable kingdom. 36 MANUAL OP OATTLE-FEEDING. Several other substances belonging to the same class have also been isolated. Scheibler* discovered betain (tri-methyl glycocoll) in mangolds, v. Gonip - Besanez f found leucin in germinating vetches, Schulze and Urich :]: have shown that glutamin is contained in mangolds, and the same body, along with some tyrosin, was found by Schulze and Barbieri § in germinating squash seeds, and it is highly probable that other similar bodies will yet be isolated. Functions in the Plcmt. — The investigations of Pf offer | on asparagin showed that this body was abundantly formed, during the germination of leguminous plants, by the split- ting up of the protein of the seed, and, after being dissolved in the water always present and thus transferred to the young plant, was reconverted into protein. That is, it served, by virtue of its solubility and diffusibility, to render available to the plant the insoluble albuminoids of the seed. Later researches by E. Schulze, ^ and especially by Borodin, ** seem, however, to show that the formation of asparagin is not limited to germination, but that the trans- fer of protein from one part of the plant to another which is continually taking place during growth is also effected by the agency of this and other amides. Borodin also believes that asparagin (and other like bodies ?) is being continually produced in the living plant. According to him, the respiration of the plant takes place * Zeitschiift fur Riibenzucker-Industiie, XVI., 229. ■j-Ber. Deut. Chem. Ges.,VII., 147. tVersuchs-Stationen, XX., 193. §Landw. Jahrbiicher, VI., 681. 1 Jahrbucher fur Wiss. Botanik, VIII., 530. Tf Landw. Jahrbiicher, VII. , 411. ** Botaiiische Zeitung, Jahrg. 36, Nr. 51 and 52. MANUAL OF CATTLE-FEEDINO. 37 at the expense of the albummoids of the protoplasm, which are decomposed with formation, of asparagin. Under nor- mal conditions, the latter is regenerated to protein, but under certain circumstances it may accumulate iu the plant. According to Schulze, various amides are formed in this process, some of which are rapidly regenerated, whUe others are utilized but slowly, and hence accumulate in comparatively large quantities. This view is supported by the results of KeUner,* who found a considerable amount of amides in a large number of growing plants. His experiments were made chiefly on fodder plants, in some of which over 30 per cent, of the total nitrogen was found to exist in amide form, but con- siderable quantities of these bodies were also found in the green parts of several species of trees. Furthermore, Schulze and Urichf have shown that beets, and, presumably, other roots, contain large quanti- ties of amides, and that in the second year's growth they pass into the plant and serve as a source of protein. Amides have also been found in considerable amounts in potatoes, where they doubtless perform a similar function. It is but recently that investigation into the proportion of amides in fodder-plants has been begun, and our knowl- edge of the extent of their occurrence is still quite limited. In view of the importance of the matter, it is earnestly to be desired that it should receive a speedy and thorough in- vestigation, extending at least so far as to determine the average proportion of albuminoids and non-albuminoids in our common feeding-stuffs. * Landw. Jahrbiioher, VIII., I. Supplement, 243. t Versuchs-St^tionen, XX., 314 38 MANUAL Of CATTLE-FEEDING, I 3. NoN-NrrEOGENOTJS NuTBIEaiTS. Caebhydeates. — The chief substances composing this group of non-nitrogenous nutrients are cellulose, or woody- fibre ; starch / dextrine / cam,e, grape, milk, and fruit sugar ; and the gutns. " These bodies, especially cellulose and starch, form by far the larger share of all the dry matter of vegetation, and most of them are distributed through all parts of plants." They owe their name to the fact that they all contain, besides carbon, the elements hydrogen and oxygen in the proportions in which the latter exist in water. This similarity of composition and their ready transformation into each other, both artificially and in the plant, show that they are nearly related chemically. Cellulose. — All plants consist of cells or microscopic closed sacks or tubes adhering together. The walls of these cells are composed of cellulose, and hence the latter is a constituent of all vegetable tissue, constituting, as it were, its frame-work. In those parts of the plant where greater strength is needed, the originally thin walls of the cells increase greatly in thickness, and often become im- pregnated with a harder substance or substances known as lignin, making them still tougher. This is especially the case with the stems. Foliage, and the husks, etc., of fruits, also contain much cellulose. Properties. — Pxu-e cellulose is an odorless and tasteless solid, varying somewhat in appearance, according to its source, but usually white in color, and with a silky or horny lustre. Cotton, flax, and hemp, and cloth and unsized paper made from them are examples of nearly pure cellu- lose. It is distinguished from the other bodies of this group MANUAL OF CATTLE-FEEDING. 39 by its slight solubiKfy; neither dilute acids nor alkalies, water, or any of the ordinary solvents, dissolve it. Hence, it may be obtained by acting on vegetable matter with various solvents till all other substances are removed. If cellulose be exposed for some time to the action of strong oil-of -vitriol, or be boiled for some hours with dilute acids or alkalies, it is converted first into dextrine and then into grape-sugar. If treated with iodine and tlien with strong sulphuric acid, it assumes a deep-blue color. This reaction serves to identify cellulose under the microscope, CoTTbposiUon. — ^Pure cellulose has exactly the same com- position as starch, viz. : Carbon 44.44 per cent. Hydrogen 6:17 " Oxygen 49.39 100.00 As intimated above, however, it is seldom found pure, except in the young and tender parts of plants, but is usually more or less impregnated with substances to which the collective name of lignin has been given, and the follow- ing composition assigned : Caxbon. 55.3 per centi Hydrogen 5.8 " Oxygen 38.9 " 100.0 This is, however, simply the inferred composition of what is left after cellulose has been removed, and not the result of direct analysis. But it is certain that lignin (using the name in a collective sense) is richer in carbon than cellulose, and as a membrane becomes impregnated with the former, its percentage of that element increases. 40 MAirUAL OF CATTLE- FEEDING. Digest'iMUty. — CeUiilose was long thouglit to be indiges- tible. Haubner * was the first to show that this belief was er- roneous, and that the ruminants were capable of digesting large quantities of this substance. His results have since been verified in innumerable digestion experiments, which have shown that cellulose forms an important ingredient in the fodder, not only of ruminants, but of all our herbi- vorous domestic animals. The proportion of cellulose which is digested varies very considerably according to the kind and quality of the fodder and the species of animal to which it is fed. Of the cellulose of the ordinary coarse fodders, from about 30 to 70 per cent, is digested by ruminants, while the cellulose of the cereal grains seems much less digestible. In general, the younger and more tender a feeding-stufF is, the greater is the amount of cellulose which is digested, while in old and woody plants, in which much lignin is formed, its digestibility is considerably less. The lignin itself appears to be entirely indigestible. Determwiation. — The amount of cellulose in a fodder is usually determined by successively boiling the finely divided material with dilute acid and dilute alkali, and washing with alcohol and ether. These solvents remove the other constituents of the fodder and leave the (impure) cellulose behind. The residue, after deduction of the small quantities of ash and albuminoids which it still con- tains, is designated && crude fibre. It is by no means pure cellulose, but is chiefly a mixture of the latter with lignin. The crude fibre obtained from * Amts- und Anzeigeblatt f. d. landw. Vereine des Konigreicha Saohsen, 1854, Nr. 6 ; also, Zeitsohr. f. D. Landw. 1855, 177. MANUAL OF CATTLE-FEEDING. 41 different fodders according to this method has a varying appearance and comjiosition ; the crude fibre, e. g.^ pre- pared from hay and straw, contains 45 to 46 per cent, of carbon, while that from clover hay and the straw of the legumes contains 48 to 49 per cent, of the same element ; that is, the latter is richer in lignin than the formed. It is evident from these considerations that the crude fibre is not a definite body, but a variable mixture of several substances. The method just described is, indeed, simply a conventional one, agreed on by chemists for lack of a better, and the term crude fibre simply means the residue obtained by treating the fodder in the prescribed manner. The results, especially when combined with digestion ex- periments, are of great value, but it is still much to be re- gretted that no more accurate method has yet been devised. Starch. — ^Next to water and cellulose, starch is the most abundant substance in the vegetable world, being found in all plants and in almost all parts of them. It appears to be first formed in the green leaves, as the product of the reduction of the carbonic acid of the air under the in- fluence of simlight, and from thence to be distributed, by a process of solution and redeposition, to all the organs of the plant. It is found in large quantity in the seeds of the cereals, wheat, e. g., containing 61 to 76 per cent, of it in the dry substance, and constitutes a large proportion of the dry matter of potatoes and other tubers.* Properties. — ^Pure starch is an odorless and tasteless white powder, which, when examined under the micro- scope, is seen to consist of minute organized grains. These starch gi-ains are formed in the plant by a process of * The artichoke and some other tnbers contain, instead of starch, a body closely resembling it, called inulin. Innlin exists in plants both as a liquid and in grains. It gives no coloration with iodine. _^ 43 MANUAL OF CATTLE-FEEDING. growth, and vary in size and appearance according to the species of plant which produces them, so that starch from different sources can be readily distinguished. They are composed of two substances — a skeleton of a material resembling cellulose and called sta/roh-oeUulose, and a more soluble substance called gra/mdose, which constitutes by far the larger part of the grains. A characteristic property of starch is that, when brought in contact with a minute quantity of iodine in solution, it assumes a beauti- ful blue, color. This property seems to reside in the granu- lose, since, if this be removed by solvents, the residue gives no longer a blue but a yellow color with iodine, like ordinary cellulose. Starch is insoluble in cold water so long as the grains remain whole. If they are crushed and groimd very fine with water, a minute quantity is dissolved. When heated with water nearly to boiling, the grains swell and burst, absorbing water and forming a jelly-like mass, but very little starch is really dissolved by this treatment. Starch, like cellulose, may be converted into dextrine and grape-sugar by boiling with acids or alkalies, but much more readily. The same transformation may be effected by dry heat, and by the action of diastase,* the ferment of malt, as in the preparation of beer and spirits. It is also rapidly dissolved and converted into sugar by the action of the saliva of the mouth and by the pancre- atic juice, and is, indeed, one of the most important of the non-nitrogenous nutrients, owing to its abundance and the comparative ease and completeness with which it is digested. * Diastase produces a pecoliai kind of sngax called maltose, instead of grape-sugar. MANUAL OF CATTLE-FEEDING. 43 TJie composition of dry starch is the same as that of cellulose, viz. : Carbon 44.44 Hydrogen 6.17 Oxygen 49.39 100.00 In the air-dry state it contains 12 to 20 per cent, of ■water. Dextrine seldom has been fomid in plants, at least in any considerable quantity, and is chiefly interesting in this connection on account of its relations to starch and sugar. It is prepared commercially in large quantities, under the name of British gum, by the action of dry heat on starch. It is formed in the same way from starch during the baking of bread, and is an important ingredient of food prepared by cooking materials containing starch. It appears to be entirely digestible. The Sugars. — There are four principal kinds of sugar, Tiz. : ccme-suga/r, obtained from the juice of the sugar-cane, the sugar-beet, sugar-maple, and other plants, and forming the ordinary sugar of commerce ; mUk-sugm', occurring in the milk of mammalia ; and gra/pe-m^gar and fruit-siigar, usually occurring together in the juices of plants and sweet fruits and in honey. Grape-sugar is also known as glucose and dextrose, and fruit-sugar as levulose. These sugars have the following composition : Carbon. Per cent. Hydrogen. Per cent. Oxygen. Per cent. Cane-sugar ) SGlk-sugar Grape-sugar J, Fruit-Bugar J ' 43.11 40.00 6.43 6.67 51.46 63.33 44 MANUAL OF CATTLE-FEEDING, They all resemble, in a general way, cane-sugar in their properties, though they are by no means identical. For our present purpose, it is sufficient to say that they are all readily soluble in water, and hence easily digestible. They are important nutrients, being formed in large quan- tities, in digestion, from other carbhydrates, though in the ordinary fodders they occur in only small quantity. The Gums. — Another group of substances of consider- able importance is the gums, of which gum-arabic may be taken as a representative. They are found in small proportions in various vegeta- ble products, and in considerable quantity in the ordinary- bread grains. They appear to be digestible by domestic animals, but of their value as nutrients we know as yet but little. Probably, however, they are practically about equivalent to starch. Mutual Relations of the Carbhydrates. — The close relationship between the several members of this group of substances which is indicated by their analogous composi- tion is shown stiU more plainly both by their ready con- version one into another, in nature and in the laboratory, and by their behavior to various reagents. In the plant, starch seems to be the first formed, and from it all the other carbhydrates are produced, while these may be converted back again into starch. In germiuation, the starch of the seed is converted into dextrine and sugar, which are carried in solution to the young plant, there to form cellulose or be reconverted into starch. In older plants, cellulose may be dissolved or con- verted into gum or vegetable mucilage. In the laboratory, all the various carbhydrates are finally converted by heat or by boiling with acids or alkalies, first into dextrine and then into some form of sugar. MANUAL OP CATTLE-FEEDING, 45 The close relationship between starch and cellulose is also shown by theu- behavior toward iodine. As we have seen, starch is colored blue by this reagent, while cellulose requires the addition of sulphuric acid (or one of several other substances) to produce the blue color. It is only the grcmulose of starch, however, which gives a blue with iodine, while the starch-ceUulose behaves like ordinary cellulose, and, on the other hand, J, Kiihn * has shown that the cotyledons of the flax-seed contain a form of cellulose which is colored blue by iodine alone. Indeed, the most recent investigations seem to show that there is a numerovis series of carbhydrates, varying from the most insoluble and resistent to the most soluble and easily attacked forms, and capable of mutual intercon- version in the plant and, to a certain extent, out of it. The Pectin StiBSTANCEs. — This group includes a num- ber of bodies of rather uncertain composition, which are the characteristic ingredients of fruit-jeUies. They are found in ripe fruits, and, together with sugar, constitute the larger part of the non-nitrogenous organic matter of the common root crops. Uncooked fruits and roots are supposed to contain a body called pectose, which, on boil- ing with water or exposure to heat, is converted into pectin, which is soft and soluble in water. It is this change which takes place in the cooking of fruit. By further heating, the pectin is converted into pectic and pectosic acids. These substances are insoluble in cold water, and constitute the essential part of fruit-jelly. Pec- tosic acid is soluble in boihng water, and hence most jel- lies become liquid on heating ; on cooling, its solution gela« finizes again. Pectic acid is insoluble, even in boiling water. * Emahmng des Bindyiehes, 6th ed., p. '49. 46 MANUAL OF CATTLE-FEEDING. By long-continued boiling, all these bodies are converted into metapectic acid, which is quite soluble and has a sour taste. All these bodies are digestible, and are not unimportant as nutrients. They probably play much the same part in nutrition as the carbhydrates. The Fats. — Composition. — The fats found in plants have essentially the same composition as that possessed by those occumng in the animal body, and already noted on page 12, viz., on an average : Carbon 76.5 per cent. Hydrogen. 12.0 " Oxygen 11.5 " 100.0 It will be noticed that these nutrients differ from those hitherto considered in containing a much larger proportion, of carbon and a much smaller one of oxygen. They con- sequently require much more oxygen for their complete combustion and give out about two and one-half times as much heat in burning as the carbhydrates, a fact of great importance in connection with the production of animal heat, and which will be treated of more fully in a subse- quent chapter. Ooctirrence. — Fat is found in small quantities in almost all plants. In roots we find 0.1 to 0.2 per cent. ; in hay and straw, 1.0 to 3.0 per cent. ;• in the cereal grains, 1.5 to 3.0 per cent., except in oats, which contain as much as 6 per cent. ; and in maize about 4 to 9 per cent. It is especial- ly, however, in the seeds of certain plants that fat or oil occm-s. The seeds of flax, hemp, colza, cotton, and numerous MANUAL OF CATTLE-FEEDING. 47 other plants, contain from 10 to 40 per cent, of oil, accom- panied generally by a considerable quantity of protein. The oil forms an article of commerce, and is commonly obtained by simply pressing the seeds. By this process, howeyer, it is impossible to separate all the fat, and in the residue of the manufacture — oil cake, rape cake, cotton-seed cake, etc. — there is left a consider- able amount (8 to 12 per cent.) of oil, together with nearly aU the albuminoids, and hence, owing to the importance of both classes of nutrients, these residues constitute most valuable fodder materials. Sometimes the oil is extracted by means of solution in bisulphide of carbon instead of by pressing. In this case the residue is valuable chiefly on account of its albuminoids, the fat content being reduced to from 2 to 4 per cent. VEilue, — In the ordinary fodder of our domestic anjmals fat plays a rather subordinate part, but in rapid fattening it is a most important aid, though, as we shall see, it is by no means the sole source of fat to the animal body. In addition to its direct nutritive effect, it also aids in the digestion and resorption of the important albuminoids. g 4. Inoboanio NunoENTS. These comprise the substances found in the ashes of plants — ^the so-called inorganic or mineral constituents. The need of these in the animal organisni and their func- tions, so far as known, have been already sufficiently spoken of in Chapter I. In all ordinary cases a ration which contains sufficient organic nutrients will also contain an abundance of the inorganic, so that commonly no special consideration of the quantity of the latter is necessaiy, with the exception of common salt, which, for reasons already 48 MANUAL OF CATTLE-FEEDING. given, is needed in larger amouats than those contained in most fodders. Such being the case it is not necessary, for the purposes of the present work, to do more than mention these sub- stances. g 5. Fodder Analysis. In the preceding sections we have indicated briefly the occurrence and properties of the most important nutrients. It only remains to describe, in a general way, the usual methods of determiuing the amount of these present in any fodder. In the present state of our knowledge it is impossible, even were it necessary, to separate and determine all the multitudinous substances which may occur in a fodder, and we must content ourselves with distinguishing the several groups of nutrients. Albuininoids. — The amount of albuminoids in a fodder has generally been found by multiplying its content of nitrogen by 6.25, it being assumed, first, that all the albu- minoids contain 16 per cent, of nitrogen, and, second, that no other nitrogenous substances are present. Neither of these assumptions being, as we have seen, strictly true, it follows that the result can only be approxi- mate, and in view of this fact it is designated as crude protein. Of the two sources of error arising under the above as- sumptions, the second is the more serious. It is only within a very short time that feeding-stuffs have begun to be ex- amined for amides, but the results already obtained show that these bodies are to be found far more extensively, and in greater quantity, in feeding-stuffs than was before sus- pected. This is especially the case with those fodders MANUAL OF CATTLE-FEEDING. 49 which, like hay, and coarse fodders in general, are cut when still immature, and with roots; while the grains appear to contain practically aU their nitrogen in the form of protein. In the present state of our knowledge a simple determi- nation of the total nitrogen of a fodder is not sufficient, but either the amide-nitrogen must be determuied or the protein must be separated from the other nitrogenous matters, by some one of the numerous methods which have been proposed, and a separate estimation of its nitrogen made. The error arising from the somewhat variable compo- sition of the numerous vegetable albuminoids we have, unfortunately, no means of correcting. In the present state of our knowledge, it is impossible to fix upon separate factors, either for the several albuminoids or for different classes of feeding-stuffs, since the same albumin- oid may vary considerably in composition accprding to its source or mode of preparation, and since the proportions in which these albuminoids are contained in the sam'e vegetable product also vary. Moreover, we have no knowl- edge whatever regarding the composition of the albumin- oids of an important class of feeding-stuffs, the so-called coarse fodders. For the present we are obliged to continue the use of the conventional factor 6.25, bearing always in mind that it is biit an approximation to the truth, though probably in most cases a tolerably close approximation. Amides. — For the determination of amides Sachsse's method is generally used. The details of the method are too technical to find a place here ; a description of the two processes proposed by Sachsse may be found in his book, ^'■Die Ch&rnie vmd Physyilogi& der Fa/i'hs1x>ffe, Kohlehyd/rate 50 MANUAL OP CATTLE-FEEDING. und Proteinsubstcmzen,^^ Leipzig, 1877, pp. 256 and 258, and a combination of the two methods, as proposed by E. Schnlze, in "Z)^'e LamdnjoiHhschqftlichen Yerauchs-Sta- tionen, XX., 117. Cellulose, as already stated (page 40), is determined by removing other substances, so-far as possible, by boiling with dilute acid and alkali, washing with alcohol and ether, and deducting from the weight of the residue the ash and albuminoids which it stiU contains. The result gives the amount of crude fihre. Fat is determined by dissolving it out of the dried fod- der by extraction with renewed quantities of common (dry) ether, evaporating off the ether from the resulting solution, and weighing the fat remaining after careful drying at 100° C. The ether extract of most grains and the residues from them can be considered as tolerably pure fat, but that of all green and coarse fodders, such as hay, straw, stover, etc., consists of a mixture of the most various substances, among which, along with the real fat, numerous wax and tar- like bodies, and especially leaf -green, or chlorophyll, occur in varying quantity. These substances are certainly of very varying importance, and in part are entirely indigestible. Ash. — The mineral matter, or ash, of a fodder is deter- mined by carefully burning a weighed quantity at as low a temperature as possible, to avoid volatilization of alkaline chlorides. From the ash thus obtained is deducted any particles of coal which it contains, and also the carbonic acid, since the latter is only formed in the burning of the organic matter, and is often very variable in quantity, according to the temperature at which the ash is prepared, so that it is not properly a constituent of the latter. MANUAL OF CATTLE-FEEDING. 61 Nitrogen-free Extract. — ^All that remains of the dry matter of the fodder, after deducting the crude protein, crude fibre, crude fat, and ash, is designated as nitrogen- free extract (N. fr. Extr.) ; that is, the quantity "of the lat- ter is determined by difference. In all grains and roots this is of a tolerably simple na- ture, and consists chiefly of starch or sugar and bodies of the pectin group, and sometimes of vegetable mucilage, which has a composition analogous to that of starch and exerts, probably, an equal nutritive effect. But in green and coarse fodders we have, in addition, varying quantities of gum-hke substances " and of lignin, which latter partly dissolves when the fodder is treated with acids and alkalies, but, at the same time, appears not to be resorbed in the alimentary canal, and therefore not to contribute to the nourishment of the animal. On the other hand, we shall see further on that all of the nitrogen-free extract which is really digested has the percentage composition of starch, and that, therefore, the non-nitrogenous nutrients of fodders, with the exception of fat, may be considered in general as carbhyd rates. The small quantities of organic acids and other bodies present are of no direct importance as nutrients, though they often have an important indirect influence, either by imparting to the fodder an agreeable taste or smell, or the reverse, by some specific physiological action, or by impart- ing undesirable properties to the products of the animal —e. g., the well-known effect of cabbage, rape cake, or onions on milk. Nutritive Ratio, — Along with the composition of a fodder we usually find given its nutritive raUo, by which we understand the ratio of the digestible protein to the digestible non-nitrogenous nutrients. 62 MAWtTAL OF OATTLE-FEEDING. From tlie results of large numbers of digestion experi- ments, we are able to teU, witb a good degree of certainty, wbat percentage of tbe several nutrients of any fodder is digestible, and these results are to be found in tables of " digestion coefficients." Suppose, now, that we have the analysis of a sample of average meadow hay of the following composition : Water '. 14.3 percent Ash 6.3 " Protein 9.7 " Crude-fibre 26.3 " Nitrogen-free extract 41.0 " Fat 2.5 " 100.0 The average of all available experiments shows that the following proportions of the different nutrients are digest- ible : Protein 56 per cent. Crude-fibre 57 " Nitrogen-free extract 63 " Fat 48 " We therefore multiply the amount of each nutrient con- tained in the fodder by the corresponding digestion co- efficient, and obtain the following results : Digestible protein =: 9.7 x 0.56= 5.4 per cent. crude-fibre =26.3 x 0.57=15.0 " " extract =41.0x0.63=25.8 " " fat =2.5x0.48=1.2 " The digestible portions of the crude-fibre and nitrogen- free extract have been shown to have the composition of starch, and may be considered as of equal nutritive value, MANUAL OF CATTLE-FEEDING. 63 pound for pound ; but the fat produces a greater effect in tlie body than an equal weight of carbhydrates, and this fact must be taken into account. It was formerly believed that the non-nitrogenous nutrients served chiefly as fuel in the body to maintain the animal heat, and that since a poimd of fat yields two and one-half times as much heat when burned as a pound of starch, it was therefore two and one-half times as valuable a food, and hence, in calcu- lating nutritive ratios, the fat was reduced to its " starch equivalent " by multiplication by 2^. We now know that this is but a partial and, for purposes of feeding, a mis- leading view, and it is probable that in time the present factor, 2i, will be replaced by a more correct one ; but that time is not yet, and, in the meantime, we must follow established custom, for the sake of rendering our analyses comparable with others. We therefore make the following calculation : Digestible fatx2i = 3.0 Digestible fibre =15.0 Digestible extiact =25.8 ' 43.8 Digestible protein = 5.4 The nutritive ratio, then, is 5.4 : 43.8, or 1 : 8.1,; the quantity of digestible protein being usually taken as unity- CHAPTER m. DIGESTION AND RESORPTION. § 1. Digestion. Introductory. — The nutrients described in the preced- ing chapter, as they occur in the ordinary fodders, are not in suitable condition to become at once part of the body. They must be separated from the various useless substan- ces with which they are associated, and be converted into soluble forms, before they can be taken up into the circula- tion and so serve to nourish the body ; — that is, they must be digested. " The digestive apparatus has been compared to the fit- tings of a pharmaceutist's laboratory in which extracts are prepared from organic substances. As, there, the mass to be extx'acted is pulverized by mortars, rasps, knives, and similar tools, so are the feeding-stuffs by the teeth of the animal ; what is effected there by water, alcohol, ether, and other extracting fluids, the digestive juices which are se- creted by various glands, and with which the whole mass to be digested is saturated, do in the animal body. " As, in the laboratory, the sufficiently extracted materials are filtered to obtain the finished extract, so the filtration of the extracted nutrients in the animal body takes place through the membranes of the intestines. " In the laboratory, the finished extract is received into a suitable vessel, and tlie worthless residue iri thrown away ; in the body, the blood and lymph vessels receive the ex- MANUAL OF OATTLE-FEEDING. 55 tracted nutrients, while tlie undissolved residue, whicli has no nutritive vahie, is removed from the body in the form of the solid excrements. " There exists, however, one great difference between the extracts prepared in the laboratory and those produced in the animal organism ; the former contain, unaltered, the soluble matters which were present in the crude materials, while the constituents of the latter are essentially different from those contained in the food. " This difference is due to the fact that the action of the digestive iluids is a more energetic one, and is accompanied by a chemical alteration of the dissolved substances." — {Set- tegasi.) Mastication and Insalivation. — The process of diges- tion takes place in the alimentary canal, consisting of the mouth, gullet, stomach, and small and large intestines. The first step in the process takes place in the mouth, and consists, in the first place, of the act of mastication, by which the food is broken up and thus made to expose more surface to the action of the digestive fluids. At the same time certain glands (salivary glands), opening into the mouth, pour out abimdantly a fluid known as the saliva. The secretion of the different salivary glands varies considerably in appearance and properties. The mixed sa- liva, as it is found in the mouth, is a watery, alkaline, somewhat slimy, transparent or slightly turbid fluid, con- taining from one-half to one per cent, of solid matter. This fluid is mixed thoroughly with the food during mas- tication, and serves to moisten and soften it and so to bring it into a suitable condition to be swallowed and further acted upon. Besides moistening the food, however, the saliva con- tains a ferment, called j)tyalm, which has the power, at 56 MANUAL OF OATTLE-FEEDING. the temperature of the body, of acting upon starch with verj much the same results as boiling dilute acids or alka- lies, viz., converting it into a form of sugar, *. e., a soluble substance which can easily pass into the circulation. To how great an extent this action takes place is a somewhat dis- puted point, but there seems to be little doubt that it is at least of some consequence, though it by no means completes the digestion of the starch, especially in animals having a simple stomach. Moreover, the saliva, being a very watery secretion, dissolves the soluble matters of the food, and forms, to a certain extent, an aqueous extract of it. Rumination. — From the mouth, the food, after being formed into morsels by the tongue, passes through the gullet to the stomach. In animals with a simple stomach, the horse or hog, e. g., the acts of mastication and in- salivation are performed com- pletely at first, but in the case of animals that chew the cud (ruminants), the food is at first only slightly chewed, and then passes into one of the divisions of their compound stomach. The stomach of the ruminants consists of four divisions, as shown in outline in fig. 2. The slightly-chewed masses pass first through the gullet, a, into the largest division of the stomach, the paimch or first stomach, 55, and partly also into the second stom- ach or reUcuhim, c. Here they remain for a time, imtil softened by the sa- Fio. 2.— (J. Kilhn.) MANITAL OF CATTLE-FEEDING. 67 liva and the alkaline fluid secreted by the stomach itself. What is dissolved here passes directly on through the other divisions of the stomach, while the undissolved sub- stances pass, a portion at a time, into the gullet, and are returned to the mouth to be thoroughly chewed and mixed with saliva. From the opening of the gullet into the first stomach, a passage called the c&sopJwyea/n, demi-ccmal leads by the paunch and reticulum to the third stomach. This canal may be described as a continuation of the gullet, having a slit in its lower wall which forms an opening into the first and second stomachs. When the food is swallowed the first time, its bulk seems to open the slit in the canal so that it passes into these two stomachs as already stated. Wlien swallowed the second time, a portion of it passes through this slit back into the first and second stomachs, but much of it goes on into the third stomach (pmamj/m or Tnwnifolds), d, from which it does not return again to the moirth. The interior surface of this division of the stomach is composed of numerous folds of mucous membrane, between which the food is received and subjected to more or less mechanical action, while the numerous capillary blood- vessels which the folds contain take up whatever materials are dissolved. From the omasum the food passes to the fourth stomach, ahomasum or rennet, e, there to undergo the ordinary pro- cesses of digestion in the same manner as in animals with a simple stomach. So long as the young animal lives on milk alone, the first three divisions of the stomach remain undeveloped, and the food passes directly into the fourth; but as it 58 MANUAL OP CATTLE-FEEDING. begins to eat more voluminotis food the first three are de- veloped and begin their functions. Liquid foods, in the full-grown animal, pass partly into all four stomachs. The ruminants are thus especially adapted by nature to digest and utilize large volumes of coarse and relatively poor fodder, straw e. g., and to extract from them the nutrients which they contain. The opinion has been almost universally held that a cer- tain volume of fodder is essential to the well-being of rumi- nating animals, and that, when concentrated feeding-stuffs are used, they must be supplemented by a suitable amount of coarse fodder, such as hay or straw, in order that the im- portant function of rumination may not be disturbed. There is no doubt that a bulky fodder is the natural food of ruminants, but the somewhat famous experiments of Mr. LiQus W. Miller, of Stockton, N. Y., seem to show that rumination may be suspended for a considerable time with no 'injurious results. Mr. Miller states that for several years he has success- fully wintered his cows on corn-meal exclusively, feeding about three quarts per day and head, and that, although rumination has been entirely suspended for some months, no ill-effects were observed. Several others have also tried his system with favorable results. The question of the sufiiciency of such a ration we shall consider further on, but although the experiments have been the object of much criticism they certainly seem to show that a bulky fodder is not so essential to ruminants as has been supposed. Naturally, however, coarse fodders will continue to form the basis for the rations of our farm animals under most circumstances ; and since, in that case, the process of diges- MANUAL OP CATTLE-FKEDING. 59 tion iiS a complicated and a slow one, the animals should be allowed the necessary time and repose to complete the act of rumination undisturbed. Gastric Digestion. — In the fom-th stomach of rumi- nants and the simple stomach of other animals, the food is subjected to the action of the gastric juice. This fluid is produced by innumerable small glands, imbedded in the inner coat of the stomach, which, when excited by the pres- ence of solid matter in the latter, pour out abundantly a clear, colorless fluids having a sour taste and smell, and containing two characteristic ingredients. One of these is muriatic acid, the chlorine of which comes from the salt of the food ; the other is ^pepsin, an or- ganic substance about whose composition and properties little is known with certainty, but which acts powerfully, at the temperature of the body, on the albuminoids of the food. Its first effect on the solvhle albuminoids is to coagulate them. Afterward, however, the pepsin, in the presence of the muriatic acid of the gastric juice, acts on the coagulated or the originally solid albiuninoids, and converts them into substances called j>eptoiies, having much the same proper- ties as protein, but soluble in water, and hence easily taken up into the circulation. The formation of peptones fiom albuminoids seems to be accom- plished by the assimilation by the latter of the elements of water, being similar to the formation of dextrine and sugar from starch by the ac- tion of acids or alkalies. Indeed, albumin, when treated with acids, yields peptones. According to Hoppe-Seyler,* the chief action of pepsin consists in this, that it unites with the muriatic acid present, transfers it to the • "Physiologische Chemie," 1878, p. 231. 60 MANUAL OP CATTLE-FEEDING. protein, unites with a fresh quantity, transfers this, again, to the pro- tein, and so on to an indefinite extent. If this be true, the similarity between the action of the gastric juice and that of acids is very close. The quantity of pepsin concerned in this process is very small, and it is found that the same pepsin is capable of acting over and over again and converting apparently un- limited quantities of albuminoids into peptones, provided that more acid is added from time to time. It is stated that the digestion of the albuminoids by the pepsin and muriatic acid of the gastric juice, and their conversion into soluble peptones, is facilitated by the pres- ence of a little fat in the food, and by salt, which causes an increased secretion of the gastric juice. It is hindered by dilution of the gastric juice by large amounts of drink, and too high or too low a temperature of the drink may, by destroying the pepsin, suspend the digestion altogether, until new pepsin can be secreted. The action of the gastric juice on the food is aided by a peculiar action of the involuntary muscles which form one of the coats of the stomach. These keep the food con- tinually in motion in the stomach, and in this way mix it thoroughly with the gastric juice, so that all parts of it may be acted upon. By means of the gastric juice, aided by the motion of the stomach just described, portions of the food are dissolved, and the whole converted into a more or less fluid mass called chyme. A portion of the chyme is resorbed in the stomach, and passes directly or indirectly into the circulation. This is the case with the sugar produced from the carbhydrates of the food by the saliva, with the vegetable acids, and in general with the easily soluble constituents of the chyme, MANUAL OF CATTLE-FEEDING. 61 and with water. They are largely (not entirely) taken np by the blood-vessels of the stomach. Some of the pep- tones are also resorbed in the stomach, though not into the blood-vessels but into the lymphatics, but a large part of them, along with the portions of the food not yet acted on, leaves the stomach through a valve, called the pyloinis, at its lower end {y, fig. 2), and passes into the intestines (s'.fig-a). Intestinal Digestion. — The mtestmes foi-m a long tube, folded and bent many times upon itself, which, together with the stomach, liver, and a few other organs, fills the cavity of the abdomen. Its length varies very considerably in different animals. In carnivorous animals, which live on easily-digested and concentrated food, it is from four to six times the length of the body; while in herbivorous animals, which feed on vo- luminous fodder, it is very much longer, being ten to twelve times the length of the body in the horse, twenty times in the ox, and twenty-five to twenty-six times in the goat. It is divided into two principal parts — the small intestine, be- ginning with the stomach and forming about f to |^ of the whole length, and the large intestine, ending with the anus. The movement of the food through the intestines is accomplished by a peculiar worm-like motion of the latter, resembling that of the stomach and called the peristaltic motion. It is produced by the involuntary muscles of the intestines, and effects both a forward movement of the food and a mixture of it with the various digestive fluids to whose action it is subjected. Chief among these digestive fluids are the bile and the pancreatic juice. The bile, or gall, of the herbivora is a dark yellowish- green liquid, secreted by the h'ver, the largest gland iji the 62 MANUAL OF OATTLE-FEEDUiTG. body, and, in most animals, stored up in tlie gall-bladdei till it is needed. The composition of the bile is very complex, and need not be taken up in detail here. It contains two character- istic coloring matters, hilirubin and MH/verdin, but its most important and necessary ingredients are compounds of soda with certain organic acids, viz. : glycocholic and taurocholic, and in the hog hyoglycochoUc acids. The soda of these compounds comes almost entirely from the salt (sodium chloride) of the food, while the same substance furnishes chlorine ' for the equally necessary muriatic acid of the gastric juice. The chief action of the bile is on the fat of the food. A small portion seems to be decomposed by the soda salts of the bile, forming soluble soda salts of the fatty acids (soaps) ; but the main effect is to emulsify the fat, that is, to separate it into minute globules like the butter globules in milk, and to hold these globules suspended, so that the whole forms a thin fluid resembling milk and called an emulsion. This fluid can be taken up by the resorbent vessels of the intestines when the latter are wet with bile. Besides its function of digesting the fats, the bile serves to hinder, to some extent, the decay of the easily decom- posable albuminoids. "When bile is added to the contents of the stomach in the state in which they enter the intestines, the peptones which they contain, as well as the pepsin, are precipitated and the digestive process is stopped. A further addition of bile, however, redissolves the precipitate, but since the muriatic acid of the gastric juice is "neutralized by the soda of the bile, the action of the pepsin is stopped. In the in- testines, however, the latter is more than replaced by the ferment of the pancreatic juice. MANUAL OF CATTLE-FEEDING. 63 The bile is secreted in very considerable quantity, but most of what is not used in digestion is taken up by the blood-vessels and resorbents of the intestines. The color of the solid excrements is due largely to portions of the bile that escape resorption. The pomcreatiG juice, the secretion of the pancreas, or sweetbread, is a clear, viscid, colorless liquid, having a slightly salt taste and a distinctly alkaline reaction. It contains at least three distinct ferments, viz. : a difis- tase, capable of converting starch into sugar ; trypsin, which acts on the albuminoids ; and a ferment which sepa- rates fats into glycerine and fatty acids. By virtue of the first of these ferments, the starch of the food which is not acted on in the stomach is rapidly converted into sugar. The trypsin of the pancreatic juice acts powerfully upon albuminoids in much the same way as the pepsin of the gastric juice, but with the differences that trypsin acts in alkaline or at most very weakly acid solution, and that the decomposition goes further. Under the action of pepsin the albuminoids yield chiefly peptones, with small quantities of the well-known amides, leucin and tyrosin, while trypsin, on the contrary, decom- poses the peptones at first formed, and produces abundant quantities of the amides just mentioned, at least in artifi- cial digestion experiments. The action of the pancreatic juice upon the fats is a two-fold one ; it rapidly converts them into an exceedingly fine and permanent emulsion, and more slowly decom- poses them into their constituents, glyce;rine and fatty acids. It will thus be seen that the pancreatic juice is a most important secretion, acting, as it does, upon aU three 64 MANUAL OF CATTLE-FEEDING. classes of nutrients and supplementing the saliva, the gastric juice, and the bile. Iniestvnal Jhoid. — It is commonly stated that, in addi- tion to the bile and pancreatic juice, the food is acted on by a third fluid secreted by numerous little glands, known as Lieberkiihn's glands, in the nmcotis membrane of the intestines. The statements regarding the composition of this fliud and its action on the food are very conflicting, dojibtless owmg in part to the difiiculty of obtaining it un- mixed with the other digestive fluids, and there seems to be considerable doubt of its existence, which at any rate cannot be regarded as proven. Recapijtulation. — We see, then, that the whole process of digestion is simply a conversion of the solid matters of the food into forms which are soluble in water or in the digestive fluids and can therefore pass into the circulation. This is accomplished, in case of the albuminoids by the gas- tric juice in the stomach and the pancreatic juice in the intestines, in case of starch, etc., by the saliva and the pan- creatic juice, and in case of the fats by the bile and pan- creatic juice. In what part of the alimentary canal, or by what secretion, cellulose is digested, is not known. Possi- bly the pancreatic juice, which acts so powerfully on the other carbhydrates, is the agent of its solution, but this is only a conjecture. The latest view regarding the digestion of cellulose is that it is not accomplished by any specific digestive fluid, but that in the extensive digestive canal of the herbivora it undergoes a sort of fermentation, caused by the iimu- merable bacteria and other low organisms there present, and yields marsh gas, carbonic acid, hydrogen, and various soluble products. By the action of these various digestive fluids, the chyme MAiniAL OF OATTLE-FEEDING. 65 which comes from the stomach is converted into a more or less thin, milky fluid, called chyle. The ease of digestion depends on various circum- stances. Digestion is both a chemical and physical process, con- sisting of solution and chemical change of the nutrients by means of the digestive fluids, and the rapidity of this pro- cess depends, in general, upon the same conditions which determine that of similar processes outside the body. Hard and compact fodder is less easily digested than that which is soft and watery, other things being equal, simply be- cause it is not so easily penetrated by the juices, and hence exposes less surface to their action, just as coarse salt dis- solves more slowly than fine. If the nutrients are shut up in insoluble envelopes, they are protected from the action of the juices. Thus, if we have starch in a cell whose walls are incrusted thickly with the indigestible (because insoluble) lignia, the starch may be, to a large extent, protected and escape digestion. So, too, if whole grata is fed and escapes «iastication, the hard outer coats of the seed protect the interior, and the grain is frequently found with little alteration in the. ex- crements. In a chemical process, the proportions of the substances concerned are of the greatest importance. So, too, in digestion, the proportions of albuminoids, carbhydrates, and fat, exercise an important influence on the digestibility of each of these groups, though exactly in what way we are ignorant. That a moderate proportion of fat aids the digestion of the albuminoids in the stomach, has already been men- tioned. Too great an amount of fat, on the contrary, hinders digestion. 66 ' MANUAL OF CATTLE-FEEDING. If the fodder be poor in albiiiniaoids and rich in starch, the latter may escape digestion in considerable quantities ; and as it is of no value in the manure (since it only fur- nishes to the plant the elements of carbonic acid and water, with both of which it is richly supplied by the atmosphere) that which thus escapes is a dead loss, while if, on account of a too great proportion of albuminoids, a portion of these pass into the manure, they still are able to furnish the plant with the valuable element, nitrogen. In a properly proportioned fodder, however, the quan- tity of really digestible matters that escapes digestion is comparatively small, although a, perfect digestion of them is not to be expected. Small portions will escape diges- tion, either owing to their hardness and impermeability, or to their being protected by insoluble matters, or simply from the fact that they are not exposed for a sufficient time to the action of the digestive fluids. This is shown by the fact that the ruminants, in which the process of digestion is long, extending through two or three days, are able to digest more of hard and diffi- cultly soluble matters, especially of crude lil)re, than other herbivora, in which the process is simpler and shorter, the horse, e. g. ♦ § 2. Resokption. "We have seen that the process of digestion is essentially a process of solution, the various nutrients of the food be- ing altered into soluble forms and dissolved by the diges- tive fluids. But the digested food, so long as it remains in the ali- mentary canal, is, to a certain extent, stiU outside the body ; it has not yet been taken up into its vessels and be- come really a part of it. It must still be resorhed or taken MANUAL OF OATTLE-FEEDIIira. 67 up into tlie circulation by the resorbent vessels which line the stomach and intestines. The Epithelium. — In all vertebrate animals, the whole surface of the intestines, from end to end, is covered with so-called epithelial cells, which are remarkably similar in all animals. These cells are roughly cylindrical, and are thickly crowded together, leaving no spaces between them. They are separated from each other by a cell wall, but are open toward the interior of the intestines, and also, ac- cording to some authorities, communicate on the other side with the lacteals. The cells contain a soft mass of protoplasm, which, when resorption is not going on, bears on its intestinal surface minute upright fibres, which give the surface of the intes- tines a velvety appearance. During resoi-ption, however, these fibres nearly disappear into the main part of the cell contents. The Villi. — In the higher animals the extent of resorb- ing surface in the intestines is greatly increased by various folds and projections of its surface, of which the most important are the viUi. These are Httle conical, round, or club-shapfed protuberances of the inner surface of the in- testines. They are covered, like all parts of the intestinal surface, with the epithelial cells just described, and imder- neatli these there is said to be a fine membrane. Beneath this membrane there are found numerous minute capillary blood-vessels, a layer of smooth (involuntary) muscular fibres, and a net-work of nei-ves. All three layers fol- low the epithelium of the intestines in all its folds and projections, and thus in the villi take somewhat the shape of a glove-finger. In the centre of each of the villi ends a vessel called a lacteal, belonging to the lymphatic system. 68 MANUAL OF CATTLE-FEEDING. Fig. 3 shows a longitudinal section of a villus, in which a represents the epithelial cells, h the capillary blood-ves- sels, c the layer of muscular fibres, and d the lacteal. Laoteals and Blood- Vessels. — The lacteals unite into larger ones leading to the mesenteric gla/nds, and after leaving these, finally join the thoracic duct, a large vessel leading forward (in man upward) and emptying into a vein in the left side near the collar-bone, called the left subclamcm vein, near its entrance into the heart. They derive their name fi-om a milky- looking fluid with which they are filled during digestion, and which owes its ap- pearance to the digested and emulsified fat of the food which has been resorbed from the chyle. At other times they contain a clear or opalescent liquid called lymph. The capillaries of the intestines also unite into larger vessels, and finally into one, the portal vein, leading to the liver. (Compare fig. 4, p. 7Y.) There the blood which it carries is distributed through a second set of capillaries in that organ, and then reunited again into a single vein, the hepatic vein, leading almost directly to the heart. Phenomena of Resorption. — As soon as the food passes from the stomach into the intestines, the resorbents of the latter begin their work, and the two processes of digestion and resorption go on simultaneously. Our knowledge of the processes of resorption is not as full as might be wished. We know that liquids and soluble substances brought into the intestines, rapidly disappear Fio. 3.— (Frey). Villus. MANUAL OF CATTLE-FEEDINa. 69 from them. In some cases the substances thus resorbed are excreted unchanged ; in others we are able to recognize the products of their decomposition without being able to say exactly where they are destroyed. "Water introduced into the intestine disappears, and is excreted iinchanged in the iirine and perspiration; sugar, on the other hand, while it is rapidly resorbed, does not reappear as such, but speedily causes an increased excretion of carbonic acid through the lungs, showing that it has been oxidized in the body. It would seem that only soluble substances are resorbed, both from the fact that sohitions are readily taken up and that the whole digestive process is di- rected toward solution of the soKd ingredients of the food. The fats, however, form to a certain extent an exception. We have seen that in the digestive process they are simply emulsified, and only to a very small extent dissolved. After a meal containing much fat, the lacteals are found to be full of a fluid having a milky appearance which the microscope shows to be due to the presence of innumerable globules of fat, which have evidently been resorbed from the contents of the intestines, having passed through the epithelial cells. Causes of Resorption. — It has been extensively taught that the phenomena of resorption are due chiefly to the action of the laws of the diffusion of liquids through mem- branes, aided by the pressure exerted on the contents of the intestines by the peristaltic motion. It is well known that, if solutions of many substances be enclosed in some membrane, like bladder or parchment- paper, and the whole placed in water, the dissolved sub- stance will difPuse through the membrane into the water until the solution is of equal strength on both sides of the membrane, and that, if the water be continually renewed. 70 MANUAL OF CATTLE-FEEDING. all the dissolved matter will finally be removed from the solution contained in the membrane. Substances which are capable of thus passing through a membrane are said to be diffusible. In the body, according to this theory of resorption, the intestines constituted the enclosing membrane, the diges- tive fluids converted the nutrients into soluble and diffusi- ble forms, while the blood and lymph of the capillaries and lacteals Mas the fluid into which diffusion took place. It was found that emulsified fats could, by slight pressure, be made to pass through a membrane previously moistened with bile, and on this fact was based the explanation of the resorption of fat, the pressure being supposed to be exerted by the peristaltic movements of the intestines, and the pro- cess of filtration to be aided by a peculiar structure of the villi which kept the lacteals in their centre under a less pressure than was exerted on the outside. In short, re- sorption was believed to consist in diffusion, combined with filtration vmder pressure. This theory has been extensively held, but the best au- thorities now consider it entirely inadequate to explain the known facts of resorption. As regards the resorption of fat, the simple fact that the villi are wanting in many of the lower animals, and that these animals nevertheless resorb fat, shows that the sup- posed peculiar structure of the villi is not essential to the process, and a more careful consideration of the anatomy of the intestinal surface shows that the filtration theory is untenable. The whole of this surface is covered with the epithelial cells above described, so closely crowded together that any filtration must take place through the semi-fluid proto- plasm of the cells. This protoplasm must behave under MANUAL OF CATTLE-FEEDING. 71 pressure essentially like a liquid, tliat is, it must exert an equal pressure upon all sides of an object enclosed in it ; under these circumstances, while diffusion may take place, filtration is impossible. But if we admit the impossi bility of filtration, the whole theory falls, for diffusion alone would, in many cases, produce results entirely dif- ferent from those observed. For example, if water and alcohol be separated by a membrane having a greater at- traction for water, the water passes through the mem- brane toward the alcohol faster than the latter passes in the opposite direction, but if alcohol, so diluted as not to injure the epithelium, be introduced into the intestines, it is rapidly resorbed into the blood, while no water passes from the latter into the intestines. Moreover, while under normal conditions water is rapidly resorbed, simple irritation of the epithelial cells is sufii- cient to cause the motion to take place m the opposite direction, viz., from the blood into the intestines. These and many other considerations force us to the belief that the epithelium of the intestines is the active agent in resorption, and that resorption is a function of the liming protoplasTn of the epithelial cells. In what manner, or by virtue of what chemical and physical laws, the process takes place, we are ignorant ; and until the relations and properties of protoplasm in general are much better known than at present, it must be regarded as a vain attempt to seek to difcover them, nor, indeed, is it important for our present purpose that we should. Course of the Nutrients after Resorption. — The substances taken up by the epithelial cells appear to pass from these into the lacteals. Their course from this point is not, in all cases, easily followed, on account of the rapid alteration which they undergo. 73 MANUAL OF CATTLE-FEEDING* The fat seems to be carried exclusively by the lacteals, and to pass through the mesenteric glands and thoracic dnct into the left subclavian vein, as already described. Other substances pass more or less completely into the blood. It will be remembered that the lacteals in the villi are surrounded by a net of capillary blood-vessels through which blood is continually passing, and there appears to be no reason why the easily diffusible substances of the lymph should not pass into the blood, especially since the latter, being continually renewed, would act like a large volume of fluid. Probably, then, the products of the digestion of the carbhydrates — viz , sugar, lactic acid, etc. — pass, in large part, into the blood and through the portal vein, the capil- laries of the liver, and the hepatic vein, to the heart. The same would be true of the amides formed by the action of the pancreatic juice and by decay from the albuminoids, and to a less degree of the peptones, while unaltered pro- tein, if resorbed, would be largely retained in the contents of the lacteals, owing to its slow rate of diffusion. All these statements are, however, to a certain extent, speculative. It is highly probable that the resorbed mat- ters undergo chemical change in the act of resorption by the epithelial cells : at any rate they undergo such rapid alteration after resoi-ption that only traces of most of them can be observed either in the lymph or in the blood of the portal vein. The Faeces. — By .the process of resorption the chyle, as it moves along through the intestines, is exhausted of its soluble parts and takes on a more and more solid con- sistency, and finally is voided from the body as the faeces. The solid excrements consist of the indigestible part of the food, those digestible parts which for any reason may MANUAL OF CATTLE-FEEDING. 73 have escaped resorption, and small portions of the diges- tive flnids and of the veorn-out mucous membrane of the in- testines. In the herbivora they also generally contain all the phosphoric acid coming from the metamorphosis of the tissues of the body, while in the carnivora this substance is excreted in the urine. The color of the excrements, as already mentioned, is usually due to the portions of the bile which have escaped resorption ; when much green fodder is eaten, its green coloring-matter (chlorophyl) passes unaltered into the faeces. The composition of the solid excrements varies largely according to the feeding of the animal. It is seldom possible to attain a complete digestion of all the nutrients of the food ; a certain portion almost always escapes digestion, unless, perhaps, in the concentrated bye- fodders. The undigested portion is generally larger when a rich food is given, *'. e., when we strive for a rapid production of organic substance, whether flesh, fat, or milk, than when the fodder is just sufficient to maintain the animal. In the former case, too, the residues of digestive fluid and of worn-out intestinal membrane are greater, owing to the greater activity of these organs and the greater quantity of juices necessary to digest the richer and more abundant fgdder, so that from fattening or milk cattle we get not only a utilization of fodder materials and conver- sion of them into valuable products, but an increase in the manurial value of the solid excrements, while in the case of animals on maintenance-fodder the manure is the only return for the fodder, and is of poorer quality than when richer food is given. CHAPTER ry. CIKCTJLATION, RESPIRATION, AND EXCRETION. § 1. ClBCULATION. The Blood. — We have seen, in the preceding chapter, that the digested and resorbed nutrients of the food are carried more or less directly into the blood, and it is from this fluid that all parts of the body derive those substances necessary for their growth and the performance of their functions. The blood of the higher animals is a thickish, somewhat viscid fluid, having a faint but peculiar odor, a slightly salt taste, and a color varying from bright to a dark red. It is somewhat heavier than water (sp. gr. 1.045 — 1.075), and contains about 21 per cent, of solid matters. Under the microscope it is seen to consist of a clear fluid, the plasma, holding in suspension a vast number of small, round disks, the corpuscles. The corpuscles are of two kinds. By far the "most nu- merous are the red corpuscles. In man these are round like a coin but thicker at the edges than in the centre, and have a diameter of .0060 — .0085 millimetres. Their number is enormous, being estimated at 4-5^ millions per cubic millimetre. The color and opacity of the blood are due to the corpiiscles. The corpuscles of each kind of animal are peculiar, both in shape and size, but their general characteristics are the FlQ 4.— Plan ol Ciroolation. MANUAL OF CATTLE-FEEDING. 75 same in all. Those of most mammals are smaller than those of man. The corpuscles contain, as characteristic ingredients, two coloring-matters, known as hoemoglobin and oxyhomioglo' bin, of each of which there appear to be several varieties in the blood of different animals. Arterial blood contains only oxyhsemoglobin. This sub- stance is a bright red, crystalline body, having pretty nearly the percentage composition of protein, but contain- ing about 0.45 per cent, of iron. Its most remarkable property, however, is the readiness with which it parts with a portion of its oxygen and is converted into haemoglobin. In the body this process takes place in the capillary blood-vessels, so that the blood as it returns from these to the heart (the venous blood) contains both oxyhsemo- globin and hsemoglobin. The latter is capable of the reverse change, and in the lungs takes up oxygen and is converted back into oxyhsemoglobin. Besides these two coloring-matters, the corpuscles con- tain an albuminoid which is precipitated by concentrated salt solution, small quantities of two bodies known as cho- lesferm and lecithin, some other organic matters, and the usual ash ingredients, potash and phosphoric acid being especially abundant. In addition to the red corpuscles the blood contains colorless corpuscles, differing in shape and appearance from the red and generally larger. They appear to be formed in the lymph before it joins the blood, but their exact function is not well ascertained. Their number is vastly less than that of the red, there being about one or two of the former to a thousand of the latter. Ths plasma is a nearly transparent fluid, containing in solution a large part of the nutritive matters of the blood. 76 MAKUAL OF CATTLE-FEEDING. Of the albuiiiinoids, it contains albumin, and blood-fibrin or at least one constituent of it ; it also contains some fat, usually traces of sugar though never large quantities of it, and a considerable proportion of mineral matters, espe- cially of soda salts and chlorides, besides miuute traces of various other substances. Coagulation, — So long as the blood remains in the ves- sels of the living body it continues fluid, even if its circu- lation be stopped, but when drawn from the body it co- agulates after standing for a time, yielding a yellowish liquid, the servmi, and blood-fibrin. At ordinary temper- atures the change takes place rapidly, but only slowly at a low temperature ; it is entu-ely hindered by addition to the blood of a strong solution of sulphate of soda, sulphate of magnesia, nitrate of soda, common salt, and other sub- stances. Opinions differ as to the nature of the coagula- tion, but it is certain that the blood-fibrin does not exist as such in the blood but is formed from a substance called fhrvnogen, contained in the plasma, and concerning which three facts may be considered as established : 1st. Fibrin is only formed in fluids which contain fibrinogen. 2d. A solution of fibrinogen alone yields no fibrin, and hence the action of some other body or bodies is reqiiisite. 3d. This other body or bodies is yielded by the colorless corpuscles. A. Schmidt, who has most fully investigated this sub- ject, regards the substances coming from the colorless cor- puscles as partaking of the nature of a ferment, and be- lieves Aat they are not contained in the living blood but are formed, after the blood is drawn from the body, by the decomposition of the corpuscles. Whether this be true or not, there is no doubt that these corpuscles yield a sub- stance capable of converting fibrinogen into fibrin. MANUAL OF OATTLE-FEEDINa. 77 The Heart. — The movement of the blood through the body, in order that all organs may receive from it their necessary nom-ishment, is accomplished by the heart. The heart is an irregularly conical-shaped organ, com- posed of involuntary muscles. It is situated in the ante- rior part of the chest, and hangs free in an envelope called the p&ncardium. It is divided by an impervious partition into a right and left half, and each of these is subdivided by a cross-par- tition into two chambers, communicating with each other by a valve in the dividing wall. The upper and smaller of these divisions are known as the right and left av/rides, and the lower and larger as the right and left ventridles. Into these divisions open several large blood-vessels, whose mouths are closed with valves so arranged that the blood can only flow into the auricles and out of the ventricles. The blood returning from the extremities of the body to the heart enters first the right auricle, a (Fig. 4), through two large veins, the vena coma wnterior, k, coming from the anterior, and the vena coma posterior, I, from the posterior part of the body. The auricle then contracts, and the blood, being prevented from returning into the blood-vessels by the valves at their mouths, is forced through the valve in the partitiofi wall into the right ven- tricle, h. This, in its turn, contracts, and the blood, pre- vented as before by a valve from turning back in its course, is pressed out of the ventricle through the pid- monary artery, c, which divides into two branches leading to the right and left lungs, d, d. The opening of this blood-vessel, like that of the others, is provided with a valve, which prevents the return of the blood. The blood, after having been purified in the lungs, returns to the left auricle.^, through the pulmonary veins, represented by e. 78 MANTTAL OP CATTLE-FEEDING. The auricle then contracting, sends the blood into the left ventricle, g, which, in its turn, contracts powerfully and expels the blood into one large vessel, the aorta, h. The aorta, soon after leaving the heart, divides into two branches, the amterior aorta, i, leading to the fore part of the body, and the posterior aorta, j, supplying the abdom- inal cavity and the posterior part of the body. These blood-vessels repeatedly subdivide and carry the blood to all parts of the body, to be brought back again to the right side of the heart and undergo the same process anew. The sole cause of the motion of the blood is the power- ful contraction of the muscles of the heart. This alter- nate contraction and relaxation constitutes the beating of the heart, and the sudden impulse thus given to the blood in the arteries causes the beating of the pulse. . The Arteries, which conduct the blood from the heart to the various organs of the body, are tubes with strong, elastic, and contractile walls, to withstand the force with which the blood is pressed into them by the heart. They originate in the aorta, A (Fig. 4), which receives the blood from the left ventricle, and as they extend farther and farther from the heart throw off branches to the vari- ous organs, become smaller and smaller, and finally end in the owpiUcvnes. The Capillaries are exceedingly fine blood-vessels which penetrate all parts of the body and form the con- necting hnk between the arteries and veins. Their walls are thin and delicate, and through them the nutritive mat- ters of the blood diffuse out into the tissues to repair their waste, while the worn-out matters, at the same time, dif- fuse into the blood. Thus all parts of the body are kept continually bathed in a solution of nutritive matters. In the capillaries, too, the oxygen which the blood has MANXTAL OF OATTLE-FEEDING. 79 taken up in the lungs unites with some of the worn-out matters and burns them, producing the animal heat. This point will be spoken of b more fully in the next section. In Fig. 4, n represents the capillaries of the posterior part of the body, those of the stomach and intestines, t those of the kidneys, p those of the liver, and m, those of the an- terior part of the body. The capillaries gradually unite together into larger Fia. s.-csettegast.) capiuariea. vessels, the veins, which convey the blood, no longer suited to nourish the body, back to the heart and lungs. The Veins are tubular vessels somewhat similar to the arteries, but with weaker and non-elastic walls, the pres- sure of the blood on them being less, owing to the inter- position of the capillaries between them and the arteries and to the fact that they are larger than the latter. To prevent any possible flowing back of the blood, the veins are provided at intervals with valves which permit the blood to pass toward the heart but not in the opposite direction. The smaller veins unite to larger ones, and finally, as already described, empty their contents through two branches into the right auricle of the heart. From the capillaries of the intestines the blood carrying the re- sorbed nutrients passes through the portal wm, s, to the liver, J9, there passes through another system of capillaries, and then rejoins the blood from the extremities through the hepatic vem, u. Into the branch, k, coming from the head 80 MANUAL OF CATTLE-FEEDING. and anterior part of the body, the nutrients which are resorb ed by the lacteals are poured just before it enters the heart. The passage of the blood from the left heart through the body and back to the right heart, is called the greater or systemAc circulation ; that from the right heart through the lungs to the left heart the jpvhnoTiary circulation. The appearance of the blood in the veins and arteries is strikingly difFerent. In the veins it has a dark, cherry- red color, but after it has passed through the lungs and is Bent out by the heart into the arteries it has a bright, scarlet color. The former is called venous, the latter arte- rial blood. An exception to this rule, that the arteries carry bright-red blood and the veins dark, is found in the pulmonary circulation, where, of course, the vessels leading from the right heart to the lungs carry venous blood, and those leading from the lungs to the left heart, arterial. Nevertheless, the general nomenclature is adhered to, and the former are called arteries and the latter veins. Arteries conduct the blood from the heart, veins towa/rd it. §2. Respibation. Under respiration we here include not, only the act of breathing, but all those chemical changes in the body of which that act is partly the cause and partly the consequence. The Lungs. — The principal organs of respiration are the lungs, which, with the heart, occupy the cavity of the chest. This cavity is enclosed on the sides by the ribs, and is separated from the abdominal cavity, containing the digestive organs, by a strong, arched, muscular partition, the diaphragm. The diaphragm is convex toward the chest, and by its contraction and a simultaneous outward motion of the ribs, caused by muscles situated between them, the size of the chest cavity is enlarged, and air MATTUAL OF CATTLE-FEEBING. 81 rushes into the lungs by virtue of the atmospheric pres- sure. This constitutes the movement of inspiration, or breathing in. The reverse motion, which immediately follows and expels a portion of the air, constitutes the movement of expiration, or breathing out. The air enters the lungs through the trachea, or wind- pipe, from the mouth and nostrils, The trachea, after reaching the chest, divides into two branches, one leading to the right and the other to the left lung, and each branch subdivides again and again into a multitude of fine tubes, called bronchial tubes, each of which finally ends ia an ulti- mate lohule, consisting of sev- eral minute vesicles. In Fig. 6, c represents the ultimate bronchial tube, i i the vesicles, and the whole mass of vesicles constitutes an ultimate lobule, a. The vesicles and tubes have elastic walls and are surrounded by an elastic tissue, so that the whole lung constitutes a spongy mass which expands or con- tracts with the motions of the chest, causing the air to flow into and out of all parts of it. The vesicles are also surrounded by a net-work of ex- tremely fine capillary blood-vessels, through which the blood sent to the lungs by the contraction of the right ventricle of the heart must pass, and the walls both of the capillaries and of the vesicles are very thin and are permeable to gases. Exchange of Gases in the Lungs. — ^The venous blood, as it comes to the lungs, is rich in carbonic acid. Fio. 6.— (Frey.) Lung Tissne, 82 MANUAL OF CATTLE-FEEDING, derived from the burning of waste products in tiie capil- laries, and for the same reason is poor in oxygen ; while the air in the vesicles of the lungs, on the contrary, is rich in oxygen and contains but little carbonic acid. Under these circumstances each gas moves from the place where it is most abundant to the place where there is a deficiency of it. The carbonic acid of the blood diffuses through the membrane of the blood-vessels into the air of thes vesicles till the latter is as rich in that gas as the former, while the oxy- gen, at the same time, passes from the vesicles to the blood. The carbonic acid is largely contained in the plasma of the blood, and simply diffuses into the air in the lung vesicles and is expelled in expiration, but for the taking up of oxygen there is a special provision in th^ coloring matters of the corpuscles. The venoiis blood contains both haemoglobin and oxyhsemoglobin. When the blood passes through the Itmgs the haemoglobin unites with the oxygen which diffuses into it, and when the aeration is properly performed is all converted into oxyhaemoglobin, which gives the arterial blood its bright-red color. The corpuscles thus act as vehicles for conveying oxygen from the lungs to the remotest regions of the body. In the capillaries this oxygen is given up again in part, and haemoglobin formed once more, giving to the venous blood its dark-red color. If by any means respiration is stopped, the air in the lung vesicles speedily becomes so charged with carbonic acid and exhausted of oxygen that the exchange of gases with the blood can no longer go on ; the carbonic acid is re- tained in the latter, the waste products of the tissues are not bui'ned, and the animal's blood is poisoned — it is suffocated. If its supply of air, however plentiful, contains more than a certain amount of carbonic acid, the removal of this MANUAL OF CATTLE-FEEDINa. 83 gas from the blood is made incomplete or suspended en- tii-ely, and substantially the same results ensue, though more slowly. Respiration through the Skin. — In addition to the exchange of gases between the air and the blood which goes on in the lungs, a similar process takes place, though to a smaller extent, through the skin. The true skin, underlying the cuticle or scarf-skin, is penetrated by capillary blood-vessels, and in its passage tbrough these capillaries the blood gives off some carbonic acid and takes up some oxygen by diffusion through the skin. The amounts thus given off and taken up are small compared with the corresponding amounts in the lungs, but they are still not inconsiderable. The skin likewise acts, by means of its sweat-glands, as a channel for the re- moval of water from the system. Large amounts of water are continually evaporating from the skin in the form of the " insensible perspiration," while under certain circiun- stances the excretion of water is so rapid as to give rise to the formation of visible drops. The distribution of oxygen through the body is accomplished by means of the circulation. Each little cor- puscle carries its load of oxygen from the lungs through the heart and arteries into the capillaries. There, as we have seen, the substances formed in the minute cells of the tissue by the decomposition of their contents under the influence of the vital force, diffuse into the bloodj^ and here they meet the oxygen con- tained in the corpuscles -and unite with it — are burned, producing the amhnal heat. Innumerable intermediate products are formed in this process, but the final result is in all cases the same. All the non-nitrogenous sub- stances yield carbonic acid and water; the nitrogenous 84 MANUAL OF CATTLE-FEEDING. ones the same substances, and in addition urea, the char- acteristic ingredient of the urine. Urea is a ciystallizable body of comparatively simple composition, which, together with small amounts of other substances, contains all the nitrogen and part of the carbon and hydrogen of the albmninoids from which it is derived. In the urine of herbivorous animals it is, in part, replaced by hippuric add. All these oxidations take place in the cells and capillaries of the body, and it is there, consequently, and not, as is sometimes stated, in the lungs, that the animal heat is produced. The quantity of oxygen -which passes into the hlood is by no means determined by the depth and fre- quency of the inspirations, but by the amwunt needed in the 'body ; that is, in the first place, by the rapidity of the decomposition of substances in the blood and tissues, as well as, in the second place, by the number and quality of the blood corpuscles. In all parts of the living body a continual decomposi- tion of its materials is going on, and all manifestations of life are intimately related to this metamorphosis of the materials of the living organism. This decomposition, as has been already pointed out, consists, in the main, in a splitting up of complex com- pounds into simpler ones, accompanied by a liberation of energy, which manifests itself in various ways. The processes take place according to fixed laws and at first in- dependently of oxygen, but the products of the decomposi- tion unite with the oxygen of the blood and regulate the amount of this substance taken up in respiration. The splitting up of substances in the body to form simpler compounds must be regarded as the primary process and the taking up of oxygen as the secondary, although it was MANUAL or CATTLE-EEEDING. 85 formerly believed that, inversely, the former was deter- mined by the latter. If, by an increased supply of food or by violent muscular exertion, this splitting up of the materials of the body is increased and facilitated, then, secondarily, more oxygen will be taken up, in order that the resulting products may be oxidized. Storing up of Oxygen. — ^We have hitherto, for con- venience, spoken as if the oxygen taken up by the blood united at once in the capillaries with the products of tis- sue change. Numerous experiments by Pettenkofer and Voit,* at Munich, and by BLenneberg,f at the Weende Experiraent Station, have, however, shown that the anim^ body has the power of storing up within itself a considerable amount of oxygen, and that some time may elapse after oxygen is taken up into the blood before it is excreted in combina- tion with carbon and hydrogen. The following experi- ment by Pettenkofer and Yoit, upon a healthy man on an average diet, will serve to illustrate the point. The ex- periment was divided into two parts, the time from 6 a.m. to 6 P.M. being designated as day and from 6 p.m. to 6 A.M. as night. If from the amount of carbon, hydrogen, oxygen, and nitrogen, contained in the food eaten, we subtract the amounts excreted in organic combination in the solid and liquid excrements, and also the amounts laid up in the body in the form of fat, etc., the remainders wUl show how much of each element must have been burned to car- bonic acid and water in the body. This known, we can easily calculate the amoimt of oxygen necessary for the process, and compare it with the amount actually taken up * Zeit. f. Biologie, II., 553. f Nene Beitrage, etc., 1871, p. 345. 86 MANUAL OF OATTLE-FEEDING. from the air, as determined by tlie method described in a subsequent chapter. In this experiment the following results were obtained : DAT. In food. In excreta. In fat formed in body. Bemain to be oxidized. Oxygon required. Carbon 340.15 195.40 1455.79 10.13 7.94 1.71 8.64 10.13 86.91 13.53 13.10 0.00 145.30 180.16 1434.05 0.00 387.46 Hydrogen 1441.38 Oxygen 1838.74 Already present. 1434.05 Needed from without 394.69 Actually taken up from air 334.70 Difference —159.99 NIGHT. In food. In excreta. In fat lost by body. Eemain to be oxidized. Oxygen required. Carbon 75.35 75.50 548.11 7.34 19.16 3.19 13.36 7.34 47.11 7.33 7.10 0.00 103.30 79.64 543.95 0.00 275.50 637.12 Hvdroeren Oxvsreu Nitrogen 912.63 Already present 543.95 Needed from without 369.67 Actually taken up from air 474.30 Difference +104.63 Difference for 34 hours — 55.36 Manual op cattle-feeding. 87 tn the night-half of the experiment, there was taken in- t<. the system through the lungs 104.63 grms. of oxygen more than was used during that time in oxidizing food substances and body-fat, while in the day-half of the ex- periment more oxygen was thus used than was supplied from without, the semainder (159.99 grms.) evidently be- ing drawn from a supply previously laid up in the body. In the earlier experiments of both Pettenkofer and Yoit and Henneberg, the storing up of oxygen took place chiefly, as in this case, in the night, but further investiga- tions showed that this was by no means always the case. It would seem, from these experiments, as if the healthy animal body were constantly either storing up or giving off oxygen, the two processes, as a rule, nearly balancing each other in the course of twenty-four hours, while com- plete equilibrium is seldom reached in that time. The significance of this fact we shall consider later. Decompositions of the Nutrients in the Body. — The albumiTioids oi the food and tissues are believed to split up, by numerous intermediate steps, into urea and Jut.* In the herbivora there are also . formed varying quantities of hi^pufic acid, according to the fodder and the species of animal, but the latter always represents a far smaller part of the decomposed albuminoids than the urea, and often disappears almost completely from the list of the substances formed and excreted as the result of tissue-change. The urea is rapidly taken up by the blood, separated from it again in the kidneys, and excreted in the urine ; it can and ought never to be stored up in the healthy organ- ism. In thejiormal blood and in the tissues are foimd only inconsiderable traces of it, although the total quan- * See the chapter on the " Foimatiou of Fat." 88 MANUAL OF CATTLE-FEEDIITG. tity which is formed daily in the body of a fattening steer may amount to a pound or more. The nitrogen contained in 100 parts of water-free pro- tein can be separated from it in the form of 33.5 parts of urea. The remainder of the protein, 66.5 parts, after taking up and uniting with 12.3 parts of water, contains the elements for the formation of 51.4 parts of fat and 27.4 parts of carbonic acid. The fat, whether formed from the albuminoids or con- tained as such in the food, is, according to circumstances, either deposited in the body of the animal, finds appli- cation in the production of milk, or undergoes a complete oxidation in the respiratory process, yielding carbonic acid and water. The fat producible from the albuminoids must always be added to that which is contained, ready formed, in the fodder and resorbed from the digestive apparatus, in estimating the results of a particular method of feed- ing. It is, however, to be observed that, according to the results of late researches, the fat formed in the body out of albuminoids appears to unite more readily with oxygen — that is, to bum easier — ^than the ready formed fat taken in the food, and this again easier than that which is already deposited in the fat-tissues. The carhhydratea are represented in the body chiefly by sugar, all the other bodies of the group being converted into this substance during digestion, so far as they are not further decomposed. The food of all herbivorous animals contains large quantities of carbhydrates, an ox, for ex- ample, often resorbing into his blood from twelve to eighteen pounds of sugar in twenty-four hours, yet the blood, in its normal state, never contains more than minute traces of this substance, and it is never stored up as such in the body. MANtJAL OF OATTLE-FEEDING. 89 The cause of the comparatively small quantity of sugar found iu the body, notwithstanding the large amounts taken into the blood, lies partly in the fact that the pro- cess of resorption is a gradual one, extending over a con- siderable time, the sugar, after it passes into the circula- tion, being oxidized with comparative rapidity, and partly, as it would appear, in the conversion of the resorbed sugar into an insoluble form by the liver. Glycogen. — The liver, as long as it is in a normal state, contains a substance belonging to the carbhydrate group, and known as glycogen, in quantities varying according to the diet of the animal. It may be extracted from the liver by hot water, and when purified forms a white, meal-Hke, amorphous pow- der, tasteless and odorless. In cold water it swells up, and on warming dissolves to an opalescent fluid. It is insolu- ble in alcohol and ether, and is colored dark-red by iodine. All those agents which convert starch and dextrine into sugar produce the same effect upon glycogen. It rotates the plane of polarized light strongly to the right, but does not reduce alkaline copper solution. It will thus be seen that it stands intermediate between starch and- dextrine. Its composition is the same as that of starch. Glyoogenie Function of the Liver. — ^If the dead liver, after removal from the body, be washed out by water injected through the portal vein till all sugar is re- moved, and if then, after standing for a time, the washing be renewed, the first portions of water that pass contain sugar. The same process may be repeated several times. " If the liver of any animal be kept for a considerable time before cooking, the amount of sugar which accumu- lates in its substance is so large as to be easily detected by the taste. The liver is decidedly sweet." — (J. Le Conte.) 90 MANUAL OF CATTLE-FEEDING. The source of the sugar in these cases is the glycogen of the liver, which, by some not well understood chemical action, is converted into siigar. The same process takes plaice vn, the liming hody. The blood ia the portal vein of flesh-fed animals contains no sugar, but the same blood in the hepatic vein, after having passed through the liver, contains a notable quan- tity of this substance, doubtless derived from the glycogen of the hver. These facts were discovered by Claude Bernard in 1853, and are undisputed, but the source of the glycogen of the liver, and its physiological significance, are questions upon which there is a diversity of opinion. In what follows we shall endeavor to present in outline that view which seems, on the whole, most probable, without, however, treating the matter as one that is finally decided. We have already called attention to the great quantity of sugar that may be taken into the circulation in the course of a few hours. This sugar is largely taken up by the capiUarie? of the stomach and intestines, and passes by the portal vein into the liver, while in the general cir- culation only traces of sugar are found. Putting these facts together, the conclusion seems almost unavoidable that the liver has the power of converting sugar into the insoluble glycogen and storing it up, to be gradually reconverted into sugar as the needs of the organ- ism demand. In other words, the glycogen of the liver is a reserve of carhhydrates. The functions of the carhhydrates in the body are, as yet, but imperfectly understood, but there can be no doubt that they play an important part in the animal econooiy. According to some, the oxidation of these substances and of fat furnishes a large share of the muscular and other MANUAL OF CATTLE-FEEDING. 91 force exerted by the body. This does not appear to be fully established, but even if we do not hold this view, we shall see, in a subsequent chapter, that there is strong reason to believe that non-nitrogenous substances play an important part in the preparation of the muscles for the exertion of force, and that a constant supply of them in the blood is an important condition of healthy activity. On the other hand, it has been shown that a large quantity of sugar in the blood is very hurtful. The office of the liver seems to be to arrest the sugar on its way from the portal capillaries and, by converting it into glycogen,, to prevent an injurious accumulation of it ia the blood, while the glycogen^ by its gradual re-conver- sion into sugar, yields a contiaual supply of this substance". Glycogen may be formed from Protein. — If a sup- ply of sugar to the blood is important or necessary, we should expect to find some provision for it in those animals which take none in their food — i. e., the ca/rnvuora. This is, in fact, the case. The liver has the power to form glycogen from albuminoids, as is shown by the fact that that substance is formed in animals fed entirely on albuminoids. This being so, there is no evident reason why the same formation of glycogen from protein may not take place in all animals. Indeed some authorities hold that it does, and that all the albuminoids destroyed in the body are first decomposed in the liver into glycogen, and urea and similar products. It will be shown in a subsequent chapter, however, that under some circumstances fat may be formed from .the protein of the food and stored up in the body, and Yoit and his followers hold that the first decomposition of pro- tein in the body yields fat and not glycogen. However this may be, it is certain tha,t a, jpart of the protein may 92 MANUAL OF CATTLE-FEEDING. be used in fat formation, and as certain that part of it may also be used by the liver as a soiu-ce of glycogen. Protein as the Sole Source of Glycogen. — The views of the glycogenic function of the liver just stated, though widely accepted, are not undisputed. Many good authori- ties hold that under all circumstances protein is the source whence glycogen is formed. According to this view, the carbhydrates of the food are oxidized in place of the non- nitrogenous products of the decomposition of protein, and protect the latter, so that they are, in part at least, de- posited in the liver in the form of glycogen, to be drawn on when the supply of carbhydrates in the food is insuffi- cient. That is, the liver has the power of preparing carbhy- drate material from protein and storing it up in an insol- uble form until such time as it is needed. Which of these two theories is true, or whether the truth lies between the two, is as yet undecided, nor is a discussion of the comparative probability of the two views in place here. Oxidations in the Body are Gradual. — In the fore- going paragraphs we have, for the sake of simplicity, spoken as if the processes of decomposition and oxidation were very simple and immediate — as if sugar were burned directly to carbonic acid and water, protein split up at once into fat and urea, etc. This is far from being the case. While the final result is as if the oxidations took place in the way spoken of, and while we are therefore justified in so 'speaking when we look at the chemical changes in the body as a whole, it must always be with the understanding that the changes which actually take place are very nu- merous and complicated, and that both their nature and location are largely hidden from us. The simple fact that MANUAL OF OATTLE-FEEDING. 93 oxygen, after it is taken into the blood, remains for a time in the system, suffices to show that the chemical phenomena in the body differ essentially from those outside it, and this is confirmed "by the little we do know of the processes themselves and by the intermediate products, numbered by hundreds, which have been already discovered. Fortunately, however, for the purposes of cattle-feeding we need only to know the final results of all these changes. and these we have indicated above, and shall presently con sider more in detail. § 3. Excretion. As the result of the continued decompositions and alter- ations going on in the body, we have a constant accumula- tion of carbonic acid, water, and urea and other nitro- genous products in the blood. The carbonic acid and urea are poisonous if allowed to accumulate in the system, and the water would produce injurious effects by diluting the blood, and means are therefore provided for the removal of these substances from the body. The Urine. — In its course through the posterior part of the body the blood passes through the kidneys, two bean-shaped organs, in which the urea and other nitro- genous substances coming from the decomposition of the protein of the body are removed from it. The blood also parts here with some of its water, and the excreted liquid, the lu-ine, passes from the kidneys to the bladder and is thence expelled from the body at intervals. Besides urea, the urine of the herbivora contains, as has been already noted, hippuric add, in which form a vary- ing but small proportion of nitrogen is excreted by these animals. In the camivora its place is taken by uric add, 94 MANUAL OF CATTLE-FEEDING. also a nitrogenous substance. The urine likewise contains traces of various other bodies, nitrogenous and non-nitro- genous, which, on account of their small quantity, are of no special importance here. Excretion of Nitrogen. — In the nitrogenous substan- ces of the urine is contained all the nitrogen of the albu- minoids decomposed in the body. This is a most impor- tant fact, and one upon which a large part of the theory of feeding depends, and consequently it is desirable to examine somewhat in detail the evidence upon which it rests, particularly since its truth is still disputed by some authors. The question is, whether the " sensible " excretions, that is, urine and dung, contain all the nitrogen which leaves the body, or whether any considerable portion of it is ex- creted in gaseous form from lungs and skin. Since, unfortunately, we have no accurate means of de- termining directly whether free gaseous nitrogen is thus exhaled, we are obliged to approach the subject in an in- direct way, and to determine whether, when no gain of flesh is made by the animal, all the nitrogen of the food reappears in the excreta. The earlier experiments on this subject showed, almost without exception, a deficit of nitrogen in the excrements, seldom an excess. Boussingault found, with a horse, a de- ficit of 24 per cent, of the nitrogen of the food ; with a milk-cow, 13 per cent. ; with hogs, 37 and 55 per cent. ; and with a turtle-dove, 34 and 36 per cent. Other ob- servers also obtained a similar deficit, though quite vari- able in amount. The extensive respiration experiments of Eegnault and Keiset sometimes showed a slight excretion of gaseous nitrogen and sometimes a slight absorption of that sub- MANUAL OF OATTLE-FEEDIN&. 95 stance, but the differences observed by them were far smaller than those obtained by most other observers. Bidder and Schmidt * appear to have been the first to express the opinion that nitrogen leaves the body only in the visible excretions ; but their experiments were too few in number to prove the point, and shortly afterward Bis- choff f published the results of nmnerous experiments on dogs, in which he observed a considerable deficit, averag- ing 30 per cent. Hoppe-Seyler also found a deficit of 15 per cent, in an experiment in which a dog was fed for seven days exclusively on meat. Volt's experiments. — Karl Yoit, in Munich, was the first to furnish decisive proof that the urine and dimg are the sole channels by which nitrogen leaves the body, and that the nitrogen of the urine is an accurate measure of the amount of nitrogenous matters decomposed in the body. He showed, in his " Physiologisch-chemisGhe Untersuch- vmgen" published in 1867, that the large deficit of nitrogen observed previously was due to faulty methods of experi- ment, and found in his own experiments either an equal- ity between the nitrogen of food and excrements or dif- ferences which were explained very simply by the gain or loss of flesh by the animal under experiment. Since that time a vast number, of similar experiments, chiefly on dogs, have been made in the Physiological Insti- tute at Munich by Yoit, in conjunction with Bischoff and later with v. Pettenkof er, which have fully confirmed the results of the earlier ones and have been of the greatest service in elucidating the laws of the formation of flesh in the animal body. The following are a few of the results : % * " Die YerdanungsBafte u. der StoflEweohsel," 1853. t " Der HajTistoff als Mass des Stoffiweohsels," 1853. i Wolff: "Bmahmng Landw. Nutzthiere," p. 249. 96 MANUAL OF CATTLE-FEEDING. Food. NiTBOOEH. DlFFKIlK»CIi. experiments. Days; In food. Grms. In excrements. Grms, Grms. Per cent. 49 6 9 6 13 14 33 8 20 58 3 8 g 2499.0 306.0 459.0 306.0 612.0 7140 1173.0 6440 340.0 986.0 153.0 408.0 2535.6 308.5 460.7 307.3 611.9 718.5 1176.9 544.3 335.3 983.8 152.6 408.3 +36.6 +2.5 +1.7 + 1.2 -0.1 +4.5 +3.9 +0.3 -48 -3.3 -0.4 + 0.3 1.0 1 0.7 ' 0.4 0.4 0.0 0.6 0.3 0.1 1.4 0.3 0.2 0.07 That this equilibrium between the excreted and ingested nitrogen was not a chance occurrence in a single animal, is shown by the fact that it was confirmed in experiments on five different dogs. Experiments on other animals have not been lacking. Kanke and Pettenkofer & Yoit have shown that the same fact is true of men, and an interesting experiment was made by Voit on a pigeon, an animal with which Boussingault found a deficit of 34 and 36 per cent. Yoit fed a full-grown pigeon for 124 days with peas, of which it consumed 3,132.4 grms. (dry weight), while its own weight rose from 3Yl grms. to 444 grms. The 3,132.4 gi'ms. of peas contained 149.4 grms. of nitrogen, and in the excrements 145.9 grms. were recovered, showing a MANUAL OP CATTLE-FEEDING. 97 loss of 2.3 per cent. In this experiment the weight of the food was more than eight times that of the pigeon, and the amount of nitrogen in the food ten times that in the animal. Taking into accoimt, also, the small weight of the animal and the duration of the experiment, the hy- pothesis of any appreciable excretion of gaseous nitrogen becomes untenable. The small deficit observed is largely explained by the fact that the animal gained 73 grms. during the experiment, and was found, when killed, to be rich in flesh. Experiments on Domestic Animals. — The impor- tance of Voit's observations for the founding of a ra- tional theory of feeding, speedily led to experiments on agricultural animals, which showed that, as was to be ex- pected, the same law holds good for them. A large nimi- ber of experiments, in which various domestic animals have received a fodder which experience has shown to be suflBcient to keep them in unaltered condition for long periods, have shown that under these circumstances all the nitrogen of the fodder reappears in the excrements. Oxen. — The earliest observations were those of Henne- berg, at the Weende Experiment Station, on oxen. His first experiments, in 1858 to 1859 and 1860 to 1861, agreed in the main with Voit's results, but, owing to the com- parative imperfection of the experimental methods then available, considerable variations were found in particular cases. Further experiments, however, made in 1865,* with improved methods and apparatus, showed that these varia- tions were due to experimental errors, and most abun- dantly confirmed Yoit's observatjbns, as the following results show: * " Nene Beitriige zui Begrandnng einer Bationellen Flitterung der Wiederkauer," p. 380. n 98 MANUAL OF CATTLE-FEEDING. Weight ot animal. Lbs. NiTBOGBK FEB DAY. DUTEBENOB. No. of Ezperiment. In food. Grms. In excrement. Grms. Grms. Percent. 1.. 2 3 6 6 1,403 " 1,529 135.5 131.0 131.0 161.5 160.0 135.0 132.0 127.5 167.5 156.5 -0.5 +1.0 -3.5 + 6.0 -3.5 0.4 0.8 2.7 3.7 2.2 GroTiven * also found approximately an equilibrium be- tween the nitrogen of the food and of the excrements of oxen fed on clover hay. A ration of 14.3 lbs. of clover hay per day and head gave the following results : 1 1 NiTBOGEH IS DZXTEBENOE, Experiment, Food. Orms. Excrements. Gims. 1 Orms. 8 days 10 days 1,087.79 ' 1,506.42 1,153.67 1,463.63 +65.88 -42.79 6.0 3.8 MUk cows. — Experiments on five different cows in three different places — ^viz., in Munich, by Voit,t at the Ex- periment Station at Mookem, by G. Kiihn,;}: and at the Hohenheim Experiment Station, by E. v. Wolff § — * Zweiter Bericht fiber die Versuchs-Statiou Salzmiinde, 1864, p. 122. t Zeitschrift fur Biologie, 1869, p. 118. XTLsaiiw. Verauchs-Stationen, XII., 450. § Die Yersuchsstation Hohenheim, 1870, p. 49. MANUAL OF CATTLE-FEEDING. 99 have shown that the visible excrements of these ani- mals also contain all the nitrogen which leaves the body. The following table gives a resume of all the results, expressed in grammes per day and head: Length of feeding. NrrBOQES IK SiFFIiBENOE. FlMe. Food. Grms. • Excre- ments.* Grms. Grms. Per cent. Honich. . . . 6 days. 241.5 238.53 -2.97 1.2 Mookem... 20 to 25 days. 130.5 122.0 +1.5 1.2 <4 121.0 117.5 -3.5 2.9 I< 117.4 113.1 -43 3.6 (1 114.5 120.0 +5.5 4.8 44 114.8 108.4 -6.4 5.6 4t 121.4 113.2 -8.2 6.7 Hohenheim Nearly 6 weeks. 165.2 164.5 -0.7 0.4 it 44 169.1 169.8 +0.7 0.4 -In case of sheep, we have to take into account, besides the excrements, the growth of the wool. The fol- lowiiig results, selected from those obtained by Marcker and E. Schulze f in a large number of experiments at the Weende Experiment Station, show that when this is done the same law holds with sheep as with other animals. * Inclnding the milk. f Jour. f. Landw., 1870, p. 301. 100 MANUAL OF CATTLE-FEEDING. Live weight. LbB. Nitrogen of fodder per day. G-nus. Nitrogen ex- creted per day. Gnus. DErFXBBKOB. Animal. Grma. Percent. m 94.7 1040 100.4 122.1 103.6 135.5 109.5 17.81 17.36 14.40 ■ 16.34 14.76 25!37 19.53 16.93 16.12 14.16 17.46 15.15 25.20 19.85 -0.88 -1.14 -0.24 +1.12 +0.39 -0.17 +0.33 4.9 I 6.6 in.&IV.(av) I. & II. " TTT, & IV. " II 1.6 6.8 S.6 0.7 in 1.7 Goats. — The following experiments, made by Stoh- mann * at the Halle Experiment Station, show that in the goat also the excretion of nitrogen takes place in the visible excreta, and that no considerable excretion of gase- ous nitrogen can occur : Live weight. Lbs. NiTBOOEH Pill SAT. DiFFZBEHCE. No. of the Animal. In fodder. Grnis. In excrements and miUc. GrmB, Ormg. Per cent. 1 II L IL I II I 81.1 63.5 81.4 63.3 85:3 66.0 83.4 23.3 23.0 21.1 21.1 23.9 23.7 34.6 23.0 33.3 21.5 31.4 33.5 33.6 34.3 -0.3 -0.8 +0.4 +0.3 -0.4 -0.1 -0.3 1.3 3.5 1.9 1.4 1.9 0.5 1.4 • Zeitschrift fiir Biologie, 1870, p. 204. MANUAL OF CATTLE- FEEDING. 101 For the sake of brevity, no description of the fodder has been given in any of the above experiments. It is suffi- cient to say that it was found by experience to be just sufficient to maintain the animals, and that the latter did not appreciably gain or lose during the trials. The duration of the feeding, when given, refers in most cases to the total length of time during which the fodder was used ; the actual investigation of dung and urine usually ex- tended over 7 to 10 days. Investigations of the Respiratory Products. — The experiments which we have already described have shown conclusively that no appreciable excretion of nitrogen takes place through lungs and skin, and direct investigations of the respiratory products have only confirmed this fact. It is ti"ue that we have no means of accm-ately determining how much free nitrogen is exhaled, but any ammonia that may pass off in this way can be very exactly determined. Such experiments have been executed, and have all shown that only miuute quantities of this gas are excreted. Thus Grouven,* in experiments on twenty-nine different individuals, obtained the following amounts of ammonia per 1,000 lbs. live weight per day : Grms. Grms. Man 0.287-0.510 Sheep 0.340-0.585 Boy 0.457-0.541 Dog 0.663-1.350 Ox 0.206-0.614 Horse :. 0.259 Cow 0.174-0.892 Ass 0.673 Calf 0.774 Goat 0.585 Hog 0.931 Other observers have obtained equally small and unim- portant amounts. Quite recently, Seegen and ]!lTowak,f in Vienna, by a * Zweiter Salzmuuder Bericht, 1864, p. 235. t Biedenuann's Cential-BIatt, 1879, p. 593. 102 MANUAL OF CATTLE-FEEDING. peculiar arrangement of the respiration apparatus, claim to have shown an exhalation of free gaseous nitrogen by various animals; but the method adopted by them de- mands such extraordinarily accurate analyses that the results obtained can as well be attributed to analytical errors as to an actual excretion of free nitrogen. Determination of Gain or Loss of Flesh. — In the foregoing paragraphs we have presented, somewhat at length, some of the evidence which shows that nitrogen is excreted to any considerable extent only in the visible ejecta. This evidence could have been greatly amplified were it necessary, but enough has been given to prove the point in question. The value of this knowledge lies in the fact that by virtue of it we can determine easily and exactly whether an animal is gaining or losing nitrogenous constituents, i.e., flesh. We need only to compare the amount of nitro- gen in the digested portion of the daily fodder of the ani- mal with that daily excreted in its urine ; or, more simply still, to compare the total amount of nitrogen in the fodder with that of all the sensible excrements, both urine and dung. If the amount in the fodder is the greater, the difference evidently must be still retained in the body as flesh. If, on the contrary, the amount is greater in the excrements, it shows as conclusively that more albuminoids have been decomposed than have been supplied, and that the animal is losing flesh. Furthermore, since the albuminoids contain on an aver- age 16 per cent, of nitrogen, we can, by multiplying the difference found by the factor 6.25, as explained on page 17, calculate the weight of albuminoids corresponding to the observed difference of nitrogen, and thus tell exactly how vhuch flesh has been gained or lost. If the amount MANUAL OV CA'ITLK-FEEDING. 103 of nitrogen found in the excrements is the same as that given in the fodder, it shows, of com-se, that neither a gain nor a loss has taken place. In a subsequent chapter we shall see that all our knowl- edge of the laws of the formation of flesh has been obtained in tills way, and that consequently the trath of those laws depends on the truth of the view that the urinary nitrogen is a measure of the amount of protein decomposed in the body. ijxcretion of Carbon. — ^The carbon of the organic matters destroyed in the body is excreted in two ways. Part of it leaves the body in the various urinary prod- ucts, but by far the larger portion is excreted as carbonic acid through lungs and skin, as already described, so that an investigation into the gain or loss of carbon by the ani- mal body requires a determination of the gaseous excreta. Excretion of Hydrogen. — ^A portion of the hydrogen of the tissues is also excreted through the kidneys, a little of it in combination with carbon, nitrogen, and oxygen, in the urea, etc., but most of it in the form of water. Considerable quantities of water are also excreted thi-ough the lungs, as is made evident by the visible con- densation of the moisture of the breath on a cold day, and likewise through the skin. CHAPTER V. METHODS OF INVESTIGATION. The practical result of a particular method of feeding shows itself, if we neglect for the moment the production of milk and wool, in a gain of flesh or fat in the body of the animal and in the production of work. We hare, then, to consider more minutely the various circumstances which are favorable or unfavorable to the production of fat or flesh, and by which a greater or less amount of use- ful exertion is made possible to the animal. ■But before so doing, it will be profitable to cast a brief glance upon the methods used in iavestigations on these subjects — on the ways and means by whose help our knowledge, especially of the laws of flesh-production, has of late been essentially increased and made clearer. § 1. DaTBRMINATION OP DlGESTTBrLITSr. Digestion Experiments. — ^While the pure nutrients are theoretically capable of being wholly dissolved and re- sorbed in the digestive apparatus, yet in practice they are so enclosed in or impregnated by indigestible matters, which protect them from the action of the digestive flu- ids, or the effect of the latter is so modified by the pres- ence of several nutrients at once, that a greater or less portion escapes digestion and is excreted in the dung. To determine the digestibility of a feeding-stuff, both the latter and the dung of the animal are carefully weighed, MANUAL OF CATTLE-FEEDING. 105 and analyzed in exactly the same way. The absolute quan- tity of each nutrient which enters and leaves the body be- ing thus known, the difference between the total amount of dry matter in fodder and dung gives the total amount of matter digested, and the difference in the amount of any particular constituent, e. g., crude fiber, shows how much of that constituent has been digested. It is a matter of com-se that the greatest care must be exercised, both in the weighing off and portioning out of the fodder, in the collection of the excrement, and in the preparation of a correct sample for chemical analysis. In fact, a high degree of accuracy has been reached in such " digestion experiments " by the help of various ap- paratus, stall fittings, and other arrangements, as may be seen from the results of control experiments, especially when the animal is of a kind favorable to the attainment of accurate results. The latter is generally the case with the smaller animals, particularly with sheep. The Time occupied in Digestion in the ruminants is comparatively long ; it has been found by numerous obser- vations, made in various ways with the same result, that after a sudden alteration of the feeding, the remnants of the former fodder are still recognizable in the excrements for as much as five days. Accordingly, in all digestion experiments, the fodder whose digestibility is to be deter- mined must be fed for a period of several days before the excrement can be safely considered as corresponding to the fodder and before a sample can be taken for analysis. This preparatory period must, of course, be long enough to insure the complete elimination of the remnants of the previous fodder ; generally it is extended to at least seven lys. This preparatory period is the more important since the 106 MANUAL OF OATTLE-FEEDING. fodder undergoes a much more intimate mixture in the long and complex digestive apparatus of the ruminants than in the shorter and simpler one of the camivora or of man. In the latter it is often possible to distinguish the excrement coming from the new fodder by its appearance simply, and if a little colored fruit be eaten, it frequently forms a sharp line of division between the two. The process of digestion in the horse and hog is, indeed, more rapid than in the ruminants ; but, nevertheless, in experiments on these animals, a similar preparatory period is observed, to insure entire accuracy. A Source of Error in Digestion Experiments. — The amount of solid matter digested must be equal at least to the difference between fodder and excrement ; it is, in fact, slightly greater, for the reason that the dry matter of the excrement is somewhat increased by the addition of certain products of the intestines themselves, and especially of por- tions of the bUe which escape resorption, so that the appar- ent digestibility of the fodder is decreased by that amount. Some idea of the amount of nitrogenous substance thus excreted, and the consequent error in the determination of the digestibility of the albmninoids, may be obtained by de- termining the nitrogen in the ethereal and alcoholic extracts of the excrement, and also the sulphur in organic combina- tion contained in the aqueous extract. The constituents of the bile are largely soluble in alcohol and ether, while the albuminoids are not ; of the bile-constituents not thus soluble only the taurin needs to be considered, and this is soluble in water and distinguished by a very large content of sulphur (25.6 per cent.), while its nitrogen amounts to 11.2 per cent. In this way it is not difficult to find the greatest quantity of nitrogen which may possibly have come from unresorbed biliary substances. MANUAL OF CATTLE-FEEDING. 107 Some experiments made in Weende by E. Schulze and M. Marcker* showed that this nitrogen, in the case of sheep fed exclusively on hay, constituted only about 4 per cent, of the total nitrogen of the excrement and equalled only about 2 per cent, of that of the fodder, so that it could not cause a very considerable error in the determina- tion of the digestibility. In the excrement of swine, which generally consume easily-digestible fodder and therefore excrete comparatively little solid matter in their dung, the quantity of biliary products is indeed relatively greater, and their nitrogen amounts, according to experiments in Hohenheim and in Kuschen, to one-fifth or even one-fourth of the total nitrogen of the excrement, but, owing to the high digestibility of their ordinary fodder, equals only 3 to 6 per cent, of the nitrogen of the latter. These biliary and other products, then, can seriously im- pair the determination of the digestibility of the albumi- noids only when the fodder is extraordinarily poor in nitrogen. For example, it was observed by Grouven, at the Salzmunde Experiment Station, that full-grown oxen on almost " starvation fodder," amounting to only 5 to 9 lbs. of rye straw, together with non-nitrogenous materials, per day, sometimes excreted more nitrogen in their dung than they received in their fodder. It is therefore difficult to arrive at even tolerably accu- rate results regarding the digestibility of the protein in substances so poor in nitrogen as the straw of the cereals, when these are fed alone ; but with even an approximately sufficient fodder, the influence of the biliary products, etc., is not at all considerable and becomes less the more nitro- genous the fodder, since it has been found, at least in the * Jour. f. Landw., 1871, p. 49. 108 MANtJAL OF OATTLE-FEEDING. Hohenheim experiments on swine, that the absolute quan- tity of these products in the excrement is no greater with a rich than with a poor fodder. Digestibility of Fat. — The determinations of the di- gestibility of fat hitherto made in digestion experiments are much less exact than those of the digestibility of albu- minoids. Most of the biliary products are soluble in ether, and as the ordinary fodder of domestic animals contains but a small quantity of fat, by the addition of these pro- ducts to the actual fat contained in the excrement the apparent digestibility of the fat must evidently be very considerably decreased, and the more so the less of it is contained in the fodder. In some experiments by E. v. Wolff, at Hohenheim,* on swine, the animals were fed exclusively with potatoes — a fodder containing but little fat — and the absolute quantity of crude fat (or, more correctly, of niatter soluble in ether) in the excrement was considerably greater than that con- tained in the fodder,, amounting to 9.48 grms., and 10.95. grms. per day and head, against 4.27 grms. and 4.91 grms. in the fodder. But, notwithstanding this source of error, digestion ex- periments yield results for fat which, although by no means absolutely correct, are yet, to a certain extent, com- parable, and have a certain worth in estimating the value of a fodder, though it must always be borne in mind that they are too low, and the more so the poorer the fodder is in fat. "We have already learned that the results obtained in fodder analysis are only approximate. They do not represent pure substances, but serve, when all analyses are carried out in the same way, to compare different fodders * Landw. Jahrbiicher, VIII., I. Supplement, p. 202. MAKUAL OF CATTLE-FEEDING. 109 with each other. The same is of course true of the analy- sis of the excrement, which is purposely made after the same method. Kemembering these facts, we comprehend that the determinations of digestibility are likewise only approximations. More accurate results are greatly to be desired, but at present we have no means of obtaining them and must be content with our present methods, which, though confessedly imperfect, have yet been of the greatest service in placing the practice of cattle-feeding on a rational basis. We can understand, then, that the pres- ence of these biliary and other products in the excrement is not so great a source of inaccuracy as it might at first thought seem, since their quantity is relatively small and is comparatively constant in the same animal, so that the results of digestion experiments are fairly comparable. At any rate, we may be sure that, if we base our calcula- tions of the amount of fodder to be given for any particu- lar purpose on results obtained by the above methods, the animals will not get less than the calculated amount of nutrients, though ^ey may receive slightly more. § 2. Dbtbkmination op the Ntttritivb Effect of a Ration. Production of Flesh. — The method of determining the gain or loss of flesh in an animal, which has been already indicated, is based on the well-established fact that the nitrogen of the urine is an accurate measure of the amount of protein decomposed in the body. K in a digestion experiment, carried out as described in § 1, the mine of the animal be also accurately collected and measured, and the quantity of nitrogen which it contains determined, we have all the data necessary to determine the gain or loss of flesh. From the determinations of the digestibility of the fodder 110 MANUAL OF CATTLE-FEEDING. we know how much nitrogen has entered into the system, while the urinary nitrogen tells us how much has left it ; the difference between the two, of course, is the gain or loss of nitrogen by the body, and since the albuminoids contain, on an average, 16 per cent, of nitrogen, this quan- tity, multiplied by 6.25, gives the gain or loss of dry pro- tein. K it is desired to know the amount of fresh flesh, with its normal content of water and ash, which has been gained or lost, this also can be calculated from the average composition of the latter. Voit,* in all his experiments, reckons, on the basis of his own and other analyses, that fresh flesh, free from fat, has the following composition : Water 75.9 per cent. Ash 1.3 " Drymatter 32.8 " 100.0 Nitrogen 3.4 " Other observers have obtained results differing slightly from this, but not sufficiently to be of serious consequence, and since so many experiments by Yoit and others are calculated on this basis, it wiU be convenient to follow the example of this eminent investigator. Assuming, then, that fresh, fat-free flesh contains 3.4 per cent, of nitrogen, we have only to "multiply the gain or loss of nitrogen ob- served in our experiment by 29.4 (3.4 per cent, x 29.4 = 100 per cent.) to learn how much flesh our animal has laid on or destroyed, while similar calculations on the total urinary nitrogen will inform us of the total amounts, re- spectively, of protein or of flesh decomposed in the vital processes. * " Etnahrang des Fleiscbfresaera," 1860, p. 304, and Zeitschrift fur Biologie, 1866, p. 468. MANUAL OF CATTLE-FEEDIHa 111 A preparatory period of feeding is, of course, necessary, as explained in the previous section, and this must be long enough to allow the body to come iuto equilibrium with the food, so that the effects of the latter may have fully developed themselves. The experiment proper must also extend over a sufficient time to give a fair average. At least twenty-four hours is necessary for this, but better results are obtained when the experiment covers several days. Finally, it should be remembered that the results ob- tained show, in the first place, only the gain or loss of ni- trogen, and that the factors used for converting this into protein or flesh are average numbers only, and that, while they are nearly enough true for practical purposes, Ihey are not absolutely accurate in all cases. Production of Pat. — ^As the production of flesh is es- timated by a comparison of the receipts and expenditures of nitrogen by the body, so the production of fat is esti- mated by the gain or loss of carbon. For this purpose it is necessary to take into account the gaseous products of respiration and perspiration, since the larger part of the carbon excreted leaves the body through these channels. These products can only be estimated with accuracy by means of a special apparatus, first constructed in a practi- cal form by Pettenkofer,' in Munich, and now widely xised under the name of " Pettenkofer's Respiration Apparatus." I%e Bespiration Apparatus.— The principles of this most important apparatus are well illustrated in an ordinary stove, in which the gases coming from the fire may represent those coming fcom the lungs of the animal. As long as the chimney dfaws, no smoke escapes from the doors and draughts of the stove, but, on the contrary, the air presses from all sides into the stove, to pass out through the chimney. 112 MAITITAL OF CATTLE-PEEDING. If, in the pipe conducting the smoke from the stoTfl to the chimney, an exact measurement of the volume of air passing \rere possible, and if, also, the composition of the air entering the stove and of that passing out could be exactly determined in an aliquot part of it, we should have all the factors needed in order to determine what had been added to the air that entered the stove by the fire inside it. In the respiration apparatus the place of the stove is taken by a small room, constructed of boiler-iron, serving to contain the subject of the experiment. This room has windows, cemented as air-tight as possible into its sides, and a door, provided with slides through which the oat- side air has unhindered entrance. The place oi the chimney is taken by large aii-pnmps which are kept in uniform motion at any required velocity by powerful clock-work, which is wound up continually by a small steam-engine. In some cases this arrangement of pumps has been replaced by a rotary blower. The air which is pumped out of the saloon is accurately measured by means of a large gas-meter, and in order to obtain an aliquot part of this air, and at the same time to analyze the air as it enters the saloon, small mercury pumps are provided, which withdraw uniformly a certain portion of air from that leaving the saloon and also from the air just before entering it. These portions of air are accurately measured by smaller meters, and their content of water and carbonic acid deter- mined by absorption of the water by sulphuric acid and of the carbonic acid by baryta water. The difference in water and carbonic acid between the air as it enters and as it leaves the saloon, calculated on the whole volume of air pass- ing through it, gives the quantity added in the apparatus, i. e., expired by the animal. It wUl be seen that the above-described apparatus is so arranged that the animal or man experimented upon is under entirely normal circumstances, i. e. , under the same atmospheric pressure and in an equally pure atmosphere as in a stall or ordinary room. This is a great advantage, because only in this way can the experiment be car- ried on as long as is desirable, and results obtained which are reliable and correspond to natural conditions. By the use of the respiration apparatus, in connection with analyses and weighings of food, drink, dung, and urine, we are able to determine all the materials put into and removed from the body, and ttus to know the exact effect of any given ration. MANUAL OF CATTLE-FEEDING. 113 The calculation of the gain or loss of flesh has already been explained. By detemiining the amount of carbon contained in the carbonic acid excreted through the lungs and skin and in the urea, etc., excreted by the kidneys, and comparing it with the amount contained in the di- gested portion of the food, we can find whether the ani- mal is gaining or losing carbon in the same manner as we can determine whether it is gaining or losing nitrogen. If the excreted carbon is less than that contained in the food, the difference must have been retained in the body ; if greater, the excess must have come from the tissues of the body. The gain or loss of carbon, however, may have been in one or both of two forms : viz., fat or albimainoids. If the comparison of the nitrogen in fodder and excre- ments shows that the body has neither gained nor lost albu- minoids, then the carbon gained or lost was all in the form of fat, since the other non-nitrogenous substances in the body are so small in amount that they can be neglected. But every 100 parts of fat contains, on an average (p. 12), 76.5 parts of carbon, and therefore every 76.5 parts of carbon shown by the experiment to have been gained or lost represents 100 parts of fat, or one part of carbon cor- responds to 1.3 parts of fat. The method of calculation is exactly similar to that nsed in calculating the gain or loss of albuminoids from that of nitrogen. The calculation is essentially the same if a gain -or loss of albuminoids has taken place, except that the amount of carbon contained in the latter must be deducted from or added to, as the case may be, that found by experiment before multiplying by the factor 1.3. An example will render this clearer. In an experiment made at the Weende Experiment Sta- tion on sheep, the animals received per day and head 1,216 114 MANUAL OF OATTLE-FEEDmO, grammes * of hay, together with the necessary amount of water. In fodder and excrements were found the follow- ing amounts of carbon and nitrogen : In Fobdbb — Hay Water , In Bxckements- Dong , Urine Expired air. . . . . Retained in body Carbon. G^rms. Nitrogen. GrmB. 460.1 18.1 0.1 .0 460.2 18.1 203.5 8.45 23.2 7.65 213.8 > ■ ■ • 439.5 16.10 20.7 3.00 Taking first the gain of nitrogen, we find that 2 grms. X 6.25 = 12.50 grms. of protein. 2 " X 29.4 = 58.80 " " flesh. and, therefore, that the animal had gained 58.8 grms, of flesh in twenty-four hours. Taking next the gain of carbon, we have to consider how much of it is due to the gain of flesh, and how much to a deposition of fat. The albuminoids contain on an average (p. lY) 53' per cent, of carbon, and hence the 12.5 grms. of albuminoids gained in this experiment contained 6.6 grms. of this element. Out of the total gain of 20.Y ♦One gramme — 15.43 grains; 1,000 grammes = 1 kilogramme = about 3. 3 lbs. MANUAL OF CATTLE-FEEDING. 115 grms. of carbon, then, 6.6 grms. were contained in the flesh laid on, leaving 14.1 grms., which must have been gained as fat. But, as. we have seen, one part of carbon is equiva- lent to 1.3 parts of fat, and hence we have — 14.0x1.3=18.2 grms., the amoimt of fat gained. So, then, the result of the ration of 1,216 grms. of hay per day was, in tliis particular case, a gain by the animal of 12.5 grms. of albuminoids and 18.2 grms. of fat in twenty-four hours. By a similar process the gain or loss of water by the body can be determined, and thus the total gain or loss, as shown by the live-weight of the animal from day to day, can be analyzed, and we are enabled to say how much of the gain which may be observed is the valuable flesh or fat, and how much is due simply to a greater or less quan- tity of water in the tissues, or of food and drink in the intestines. The following table (p. 116) gives the detailed results of the above experiment in the form of a balance-sheet, and will give some idea of the care and labor with which such investigations are conducted. Any loss by the body is, of course, placed on the " con- sumption " side of the accoimt, and any gain on the " pro- duction " side. The Live-'weight alone, although very valuable for many purposes, gives but a very imperfect idea of the effect of a ration. The live-weight of an animal includes not only the solid matter of its tissues, but also water, the food eaten, and the dung and urine contained in the rectum and bladder ; so that an increase of the live-weight by forty or fifty pounds is capable of many interpretations. 116 MANUAL 01" CATTLE-FEEDING. 1 1 1 ■s 1 1 K 1 Oonsomption. 2936.6 Food AKD Deink : 1216.0 Hay 6.0 Salt Grms. 997.4 5.7 1.8 0.8 Grms. 218.6 0.3 1712.7 Grms. 67.9 6.7 1.6 0.8 Grms. 460.1 0.1 Grms. 85.8 0.03 190.3 Grms. 18.1 Grms. 684.0 0.27 1714.5 Well-water 1522.6 8 Loss BY Body B87.6 Oxygen fbom Air 587.6 3B24.9 76.0 460.2 276.2 18.1 2694.4 Froduction. 1814.5 EXOBEMENTS: 1257.0 Dung 424.9 79.7 832.1 477.8 44.0 31.1 202.5 23.2 212.7 1.1 117.5 55.5 8.45 7.65 884 6 557.5 Urine 439 9 1640.1 BESPIB4TOEY Peodcots : 780.0 Carbonic acid 567 3 1.5 Marsli gas 0.4 95.4 0.7 0.6 2.1 4.0 858.6 Water 858.6 2.1 35.9 0.75 1.25 763.2 3.7 1 9 1.9 31.9 70.3 Gain by Body: 9.5 Wool(inolud. fat, etc.) 7.8 Protein 7.4 7.8 17.1 0.9 3.5 4.1 13.1 17.1 Fat. 36.9 Water 3524.9 76.0 160.2 276.2 18.1 2694.4 It may indicate a gain of flesh or fat, or both, or it may result simply from an increase of the water content of the tissues, or from an increased amount of food, water or dung in the intestines. The stomach alone of the ox wiU MANUAL OF CATTLE-FEEDIKG. 117 hold 100 to 150 lbs. of water. The excretion of dung, too, is more or less irregular, especially for the first week or two on a new ration. " Grouven found in many of his feeding experiments that during the first week the amount of dung excreted was often as much as twenty pounds too great «r too small." To get the most correct results from live-weight, the animals should be weighed always at the same time in the day, either before or after eating, but always under the same circumstances, so far as possible. With aU precau- tions, however, the live-weight of a thousand-pound animal may vary as much as 50 lbs. daily. Stohmann gives the following example : An ox weighed, May 33 1298.3 lbs.* " " " 24 1242.4 " « " " 30 1269.8 " « " " 31 1288.3 " " " June 3 1371.1 " " " " 4 1210.7 " " " " 13 1294.2 " It is evident from the above that the live-weight is a very uncertain criterion for judging of the effect of a ra- tion, and that for scientific purposes, where an accurate knowledge of the gain or loss of flesh and fat is required, it is almost worthless. These remarks are not to be understood as calling in question the practical value of the live-weight. The scales are (or should be) an important adjunct to the stable, but it is all the more necessary, on that account, to know how far their indications can be trusted,. while every one who * 1 German lb. equals about 1.1 English lb. 118 MANUAL OF CATTLE-FEEDING. undertakes to make feeding experiments should be aware of the exceeding ambiguity which attaches to amaU changes of weight. Tiie foregoing explanations make evident how much labor and care are necessary in order to determine, with any certainty, the nutritive value of even a single article of fodder for a single class of animals, and it is no cause for surprise that the theory of feeding can only reach its complete development in all directions slowly. When the question is only of the gain or loss of flesh, the method of experiment, as we have seen, is much simpler and less laborious and demands less expensive apparatus, than when the effect of the ration as a fat-producer is to be deter- mined ; and it is therefore natural that the laws of "flesh- building " are already very thoroughly explored, while in regard to the circumstances under which the greatest and most advantageous production of fat or work is to be ob- tained we are much more in the dark. CHAPTEE VI. FORMATION OF FLESH. § 1. Introductory. Lj the foregoing chapters we have considered the com- position of the animal body and of those substances which serve to nourish it — ^the nutrients, the manner in which these nutrients are digested and resorbed so as to become part of the body, and in outline the changes which they undergo in the body and the forms in which they are finally excreted from it. We saw that we may regard the body as composed es- sentially of protein, fat and mineral matters. The object of feeding is a production of these several ingredients in greater or less quantity. K an animal is simply to be kept in the same bodily condition — ^to be wintered, e. g. — we aim only to produce enough to supply the unavoidable destruction of tissue that goes on in every living organism, while in feeding for milk, or in fattening, we endeavor to obtain the most rapid production possible, especially of protein and fat; but in any case some production must take place. Plainly, then, it is of the highest importance to know the laws that regulate the formation of flesh (protein) and fat, from what ingredients of the food they are formed, and what quantities and proportions of the latter will pro- duce the desired effect most rapidly and cheaply. In this ohapter we shall consider the laws regulating the produc- 120 MANUAL OF CATTLE-FEEDING. tion of flesh, and in the following one those governing the production of fat. The Lavrs of the Formation of Flesh have been most thoroughly studied in the carnivora, but they are essentially the same for all the higher animals. The various races of animals differ, indeed, as regards the fodder which they chiefly consume, as well as in their greater or less digestive power for certain kinds of fodder ; but the real nutrients which are resorbed from the diges- tive apparatus, even with the most varied rations, are always the same, viz. : protein, fat, and sugar, together with water and certain salts. Since, furthermore, in all mammals at least, the corresponding organs are entirely similar in their structure, chemical composition, and func- tions, the decomposition of their constituents must follow the same course, *. e., the substances once resorbed and taken up into the circulation decompose or are laid ap in the body according to the same laws. Moreover, the laws derived from experiments on car- nivora have been completely confirmed in their general scope and bearing in all the experiments recently made on herbivora, viz., on oxen, cows, sheep, and -goats, though the total amount of material decomposed or stored up in the body varies according to the proportions of the various classes of nutrients contained in the normal fodder of the animal. The food of the carnivora consists chiefly of protein and fat, while the herbivora consume relatively less of these but large quantities of carbhydrates. The ability of the carnivora and herbivora to resorb the various nutrients is not, however, so different as is gener- ally supposed ; it has been shown, e. g., that a dog is able MANUAL OF CATTLE- FEEDING. 121 to digest and resorb, daily, as much as 15 grms. of starch per kilogramme of live weight, while a well-fed milk-cow, or even a fattening ox, resorbs from its fodder, daily, not more than 12 to 18 grms. of carbhydrates per kilogramme live weight. Similar facts have been observed regarding the resorption of protein, but not regarding that of fat, which is digested by the carnivora in relatively far greater quantity than by herbivora. A large part of our knowledge of the laws of the for- mation of flesh is due to the labors at Munich of Karl Voit, at first in eonjunction with Bischoff and, later, alone and with v. Pettenkofer. These investigators have made a great number of experiments, chiefly on dogs, de- termining the gain or loss of flesh and the total amount of protein decomposed in the body by the method de- scribed in Chapter Y., and to them belongs the honor, both of having established a reliable method of investiga- tion (see Chapter IV., pp. 94-97) and of having applied it successfully to the solution of the important question of the effect of food on the gain or loss of flesh. The results stated in this chapter are largely those of the above-named investigators. Protein Consumption. — In considering the laws of flesh-formation, there are two parallel processes to be dis- tinguished. In the first place, in every living organism a certain quantity of albuminoid matter is daily destroyed in the vital processes, and its nitrogen appears as urea, etc., in the urine. The amount of protein or flesh thus destroyed may vary greatly in different animals, or in the same animal at dif- ferent times, but it can only cease entirely with the cessa- tion of life, and cannot sink below a certain minimum 122 MANUAL OP CATTLE-FEEDING. amount without serious derangement of the vital func- tions. This continual and necessary process we shall call frotem, consumption.* This, of course, must not be con- founded with the amount consumed by the animal in its food. It denotes a very different thing. In the second place, from a sufficient and suitable fod- der more protein may be resorbed into the circulation than is needed to supply the consumption under the given circumstances, and this surplus produces a deposition of protein and becomes part of the body. Evidently, what- ever decreases the protein consumption and increases the amount deposited in the tissues is so much gained in feeding. The protein consumption is not to be considered as waste, for it is necessary to the vital processes and, as we shall see, is generally greater the richer the food, but an improperly constituted ration may unnecessarily increase it and result in an unproductive use of fodder. The smaller the protein consumption can be made, consistently vrfth the proper performance of the vital functions, the more of the protein of the food is available for the production of flesh. *We have seen (Chap. V.) that from the urinaiy nitrogen we can calculate the amount of either dry protein or fresh flesh decomposed in the body, by multiplying respectively by 6.25 or 29.4. In most of the experiments which have been made on camivora the results have been expressed as flesh, while in those executed on herbivora the re- sults have been calculated as dry protein. In the one case we should speak of the " consumption of flesh," and, in the other, of the " protein consumption." The two are equivalent, but not equal, the consumption of flesh being 4.7 times the protein consump- tion. In the following pages we shall have occasion to use both expres- sions. MANUAL OF CATTLE-FEEDING. 123 § 2. Obganized and CibcdiiAToby FBOTEm. Protein Consumptioa during Hunger. — The follow- ing table * gives, in grammes, the quantities of urea daily excreted by a fasting dog weighing about 35 kilogrammes (77 lbs.), the excretion of urea being, as we have seen, an exact measure of the protein consumption in the body. No. of Experiment. 11. 5. 14. 15. 16. PieTiouB food per day. 2,500 gnnn. meat. 1,800 grmn. meat and 250 .grms. fat. 1,600 grms. meat. 1,500 grms. meat. Grms. Grms. Grma. (ximB. Gnns. Last day of feeding 180.8 130.0 110.8 110.8 24.7 Ist day of fasting 60.1 37.5 29.7 36.5 19.6 2d " " 24.9 33.3 18.2 18.6 15.6 3d " 19.1 16.7 17.5 15.7 14.9 4th " " 17.3 14.8 14.9 14.9 13.3 5th " " 13.3 13.6 14.2 14.8 13.7 6th " " 13.3 12.8 13.0 13.8 18.0 7th " " 13.5 12.0 12.1 12.9 .... 8th " " ' 10.1 .... 12.9 13.1 .... 9th " " .... .... .... 11.9 .... 10th " .... .... .... 11.4 .... It will be observed that in these experiments the protein consumption (as measured by the excretion of urea) was very imequal on the last day of the feeding and the first days of hunger ; furthermore, that when food was with- held the protein consumption at once sank, rapidly at first but at last very slowly, till at about the si.Kth day it became • Voit : Zeitschrift fur Biologie, II., pp. 307-365. 124 MANUAL OF CATTLE-FEEDIK&. practically the same in all cases and so continued during the remaining days, its amount being represented by the excretion of about 12 grammes of urea. A large number of other experiments gave the same result. The Tvro Factors determining Protein Consump- tion. — It is plain from the above figures that there are two factors which determine the amount of protein de- stroyed in the body ; a constant one, which caused in these experiments an excretion of about 12 grammes of urea per day, and a variable one, which caused the excretion of very different quantities of urea at fii-st, and which gradu- ally disappeared as the experiments progressed. No. of Ezperimenfc. 11. 5. 14. 15. 16. PreTioas food per day. 2,500 grms. meat. 1,800 grms. meat and 250 grms. fat. 1,500 grms. meat. 1,500 grms. meat. Grms. G-rms. Orms. Grms. Grms. Last day of feeding 168.8 118.0 98.8 98.8 13.7 Ist day of fasting. 48.1 25.5 17.7 14.5 7.6 3d 12.9 11.3 6.2 6.6 3.6 3d 7.1 4.7 5.5 3.7 3.9 4th " " 5.3 2.8 2.9 2.9 1.2 5th " " 0.3 0.6 2.2 2.8 0.7 6th " " 1.3 0.8 1.0 0.8 1.0 7th " " 0.5 0.0 0.1 0.9 .... 8th " " -1.9 .... 0.9. 0.1 .... 9th " " - • ■ . .... -0.1 • . . ■ 10th " .... .... .... -0.6 Total* 244.3 163.7 135.3 131.1 29 7 * Omitting the negative quantities. MANUAL OF OATTLE-PEEDrtTO. 125 If we assume 12 grammes of urea as the amount due tc the constant factor, and subtract this from the total excre- tion on the several days in these experiments, the- remaia- ders will exhibit the action of the variable factor. In the table on the opposite page this has been done. This table shows still more clearly the great influence of the variable factor at first and its speedy disappearance when the supply of food is cut off. Organized and Circulatory Protein. — It is evident from these and a great niunber of similar results that the protein of the living body exists in two forms — a compara- tively stable one, which decomposes slowly and yielded in these experiments about 12 grammes of urea per day, and an easily decomposable one, whose amount depends on the food and which is rapidly destroyed when food is with- held. The quantity of the latter is small as compared with that of the former. In experiment 11, for example, where its amount was greatest, its total quantity was only about 3,364 grammes of flesh (244.3 grms. of urea x 13.77), while the animal weighed about 35,000 grammes. Voit designates the stable protein of the body as orgcm- ized jprot&in, and considers that it makes np the mass of the organs; while the variable and easily decomposing quantity he calls circulatory protehx. Under the latter he does not include the protein of the blood and lymph, but only the dissolved protein which penetrates from these into the tissues and bathes the cells in a nourishing fluid. Some good authorities dispute the correctness of the names circulatory and organized protein, but there is no dispute as to the correctness and importance of the distinc- tion which they imply between the two forms of protein in the body. For our present purpose this is the impor- tant thing, and we shall use Voit's nomenclature, under- 126 MANUAL OP CATTLE-FEEDING. standing by organized protein the great mass of slowly decomposing nitrogenous compounds in the body, and by cvrculatory protein the relatively small quantity of easily decomposable albmninoids whicli it contains. The quantity of circulatory protein in a poorly nourished body is only small, not amounting in hunger to one per cent, of the weight of the organized albuminoids, but its amount is increased by an abundance of protein in the food, and may, at least in the carnivora, rise to five per cent, or more. But, be the quantity of circulatory protein large or small, the greater part of it, generally seventy to eighty per cent., is consumed in the course of twenty-four hours, and an exactly corresponding quantity of nitrogen excreted in the urine as urea, etc. ; while of the organized protein, at most not more than 0.8 per cent, is consumed — that is, the protein consumption in the body takes place almost wholly at the expense of the circulatory protein. It can be by no means assumed, as was formerly done, that all organs of the body are subject to a rapid metamor- phosis, and that in the course of a comparatively short time tlie whole organism to the last atom is renewed and rebuilt. This is only the case as regards a few tissues. The blood corpuscles, e. g., and the milk glands in the period of their greatest activity, are rapidly destroyed and as rapidly re-formed ; but by far the greater part of the organs have, when once formed, a much greater stability, although the contents of the cells vary much in quantity and quality with the varying food of the animal. The circulatory protein, on the contrary', suffers a continual and rapid destruction, and must be continually replaced by protein from the food. Other Experiments. — That the organized protein of the animal body is destroyed far less easily than the circu- MANTJAL OF CATTLE-FEEDING. 127 latory protein, is also indicated by more direct experiments wtdch have lately been made. If by any means it were possible to introduce into the body of an animal which had been deprived of food long enough to destroy its circulatory protein, albuminoids in the form of a living organ from another animal, we should expect that, according to Voit's theory, these albuminoids woidd be but slowly destroyed in the body. Forster * at- tempted to accomphsh this by the transfusion of blood, and found that the proteia of living blood, which may be regarded as organized, was but slowly destroyed in the system, while simple solutions of albumin produced an immediate and considerable increase in the excretion of m-ea. It is noticeable, however, that his results show that albumen thus injected seems to be more slowly decom- posed than that taken in the food. Tschieriewf has compared the behavior of transfused blood with that introduced into the stomach, with the fol- lowing results : Nitrogen giveu. erma. Nitrogen excreted. Grms. Blood fed 13.19 19.09 14.38 0.00 18.53 14.55 6.85 " fed. 1443 No food. 4.65 10.60 These figures show plainly that the albuminoids of the blood, after they had passed through the digestive appa- * Zeitschrift fur Biologie, XL, 496. f Biedermann's ' Central-BUttt fiir Agr. Ghem.,' X., 98. 128 MANUAL OP CATTLE-FEEDING. ratus, were much more readily oxidized ia the body than before. § 3. Febding with Protein alone. Ia order to obtain a clear idea of the various factors which determine the consumption of protein, on the one hand, and its deposition on the other, it will be best, in the first place, to consider the phenomena produced when the several nutrients are fed alone, and afterward the effect of two, or of all of them together. Consiunption dependent on Supply. — The numerous researches made by Yoit * have shovm most fuUy that the consum/ption of protein in the hody is la/rgely deter- mimed hy the swpply of protein in the food. That the ex- cretion of urea, and consequently the protein consumption, was influenced by tlie food to a very considerable extent, had already been noticed, but this observer has the merit of having fully investigated the subject and given it the prominence it deserved. His experiments were made chiefly on dogs; the following are some of the results obtained in different experiments on the same dog with a diet of various quantities of pure, fat-free meat : Meat eaten per day. Urea excreted Corresponding to flesh. . . Grms. IS 166 Grms. 300 443 Grms. 500 40 B52 900 938 Grms. Grms, 1,214 1,500 106 1,463 Grms, 3,000 144 1,987 Grms. 2,500 173 2,387 Grms. 2,660 181 2,498 The consumption of flesh varied from 165 grms. per day during hunger to nearly 2,500 grms. with the largest amount of albuminoids in the food, and almost exactly in • Zeitschrift f. Biologie, III., 1. MANUAL OF CATTLE-FEEDING. 129 proportion to the amount of the latter. In all these ex- periments by far the larger part of the protein of the food was converted into drcvlatory protein, which was rapidly consumed in the vital processes. That this is always the case on a purely albuminoid diet is shown by the scores of similar experiments which might be cited. Similar experiments on oxir herbivorous domestic ani- mals have given in the maia the same result, except that the protein consumption has generally been found to be less in proportion to the weight of the animal than in the camivora, a fact which, however, as we shall see, is in great part due to the large amoimt of non-nitrogenous matter in the food of these animals. Could they be fed on pure protein, as was the dog in the above experunents, it is probable that the protein consiunption would be corre- spondingly increased. The Consumption does not depend on the Supply- alone. — With the same amount of protein in the food the protein consumption in the body may be very unequal in the same animal at different times, as the following results strikingly show. Heat eaten. Grma FreTiooB food. Consumption of flesh per day. Grms. Gain or lo» of flesh. Grms. 3,000. 2,500 gims. meat. 2,329 -271 2,000 " " +350 gims. fat. 2,069 --69 1,500 " " 1,920 + 80 200 " " -t- 300 gelatin. 1,753 + 247 1,677 + 323 450 grms. starch. 1,383 + 617 175 " meat + 300 fat. 1,365 + 635 6* 130 MANUAL OF CATTLE-FEEDING.. The same amount of food caused in one case a loss of 271 grms. of flesh, and in another a gain of 635 grms., and a corresponding variation in the protein consumption is observed. This can only be explained by the difference in the previous food. Where, by an abundant supply of al- buminoids, a large amount of drcxilatory jprotein had been formed in the body, a decrease of the albuminoids of the food caused a decrease in the protein consumption, but not to an amount corresponding to the decrease in the supply ; the animal lost flesh. On the other hand, an increased supply of albuminoids caused an increase in the protein consumption ; but the increase, like the decrease in the other case, was not proportional to the increased supply, and a gain of flesh resulted. The figures of the above table refer to the first day of the new feeding, and we gather fi-om them that the protein consumption is depen- dent not only on the amount of protein in the food but on the bodily condition resulting from the preceding feeding. Equilibrium soon established -with Food Supply. — The gain or loss of flesh observed on the first day after a change in the supply of protein does not usually con- tinue long. Within a short time — usually two to four days — the consumption of protein in the body becomes equal to the amount supplied in the food, and no further gain or loss of flesh takes place. The two following ex- amples may serve to illustrate this. Pood. Previous food. CONSOMPTION OF FlBSH. Day before. Ist day. 2d day. 3d day. 2,500 gnng. meat. 2,000 " " 1,800 gnus. meat. 2,500 « " Grms. 1,800 2,500 Grnip. 2,153 2,239 GrmB. 2,480 1,970 Grms. 2,532 MANUAL OF OATTLE-FEEDING. 131 In each, the protein consumption was in equUibrium with the food supply at the beginning of the expeiiment. In the first case an increase of 700 grins, in the amount of meat eaten caused a rapid increase in the protein consump- tion, till in three days the two were again nearly in equi- librium. In the second experiment the same thing is observed as to the decrease of the protein consumption. The gain or loss of flesh in eitlier case is very trifling,: amounting respectively to 335 grms. and 199 grms. in a dog weighing about 35 kilogrammes. Kearly all of the addi- tional 700 grms. per day in the first experiment was con- verted into circulatory proteiu and rapidly destroyed, while in the second the subtraction of 500 grms, per day de- creased proportionately the reserve of circulatory protein and the amount consumed. ' The experiments given above are simply examples taken from a large number of similar ones, made both on camivora and herbivora, all of which have given the same result, viz. : the miimaZ body puts itself, after a longer or e/iorter time, into equiltl»%um with whatever quamtity of dlhv/min- oids it receives in its fodder above that necessary to main- tain it in average condition. That is, a certain minimum quantity of albuminoids is necessary to prevent the starva- tion of the animal. An increase of the supply above this quantity causes a slight gain of flesh for a short time, but a rapid increase in the amount of circulatory protein and consequently in the protein consumption, and, finally, ex- actly as much nitrogen is excreted in the uiine (and milk) as is taken in the food. We might compare the stock of circulatory protein in the body to a mass of water con- tained in a vessel with a small aperture in the bottom. If there is no supply, it qxiickly runs out. If a small stream of water be let in at the top, a small supply of water may 132 MANUAL OF OATTLE-FEEDING. be maintained in the vessel. If a larger stream be ad- mitted, the depth of water in the vessel will at once begin to increase, but, at the same time, the pressure on the bot- tom, and consequently the rapidity of the outward flow through the aperture, increases, and outflow and inflow soon come mto equilibrium. If the supply be diminished, the level of the water sinks tiU the hydrostatic pressure causes the outflow to again equal the inflow. The Protein Consumption during Fasting is not a Measure of the Amoimt neoessajy to sustain Life, as was formerly assmned to be the case. If to a fasting animal we give an amount of protein exactly equal to that daily consumed, this protein is converted into circulatory protein, and the consumption is correspondingly increased. In order to maintain an aniriial in average condition, we must give it, approximately, from two to two and a half times as much protein in its food as is consumed in the body during hunger, and when the food has been rich in albuminoids a much greater quantity is necessary to main- tain the equilibrium once established. When equilibrium is once reached, either by a gain or loss of flesh, as the case may be, exactly the same kiad and quantity of food is necessary to keep the animal un- altered in the bodily condition in which it then is. . Every state of the body, then, demands for its maintenance a cer- tain deflnite fodder, and we cannot well speak of a super- fluous consumption of food by animals as by plants, i. e., of a wholly useless and unnecessary excess of some one nu- trient. A waste of fodder, however, often occm*s in prac- tice, in so far as more fodder is given than is necessary for the object in view, e. g., in the production of milk or wool and the feeding of draught animals and young cattle. Even in fattening, as we shall see later, the same or a bet- KANTIAL OF OATTLE-FEEDING. 133 ter result may not infrequently be obtained with a fodder somewhat poor in albuminoids than with one containing a very large quantity of them. The Rapidity "with "which Equilibrium is estab- lished varies. — It is greater the richer the food is in al- buminoids and the less fat is contained ia the body; in general, therefore, in the carnivora than in the herbivora. The influence of the fat of the body in decreasing the protein consumption is of great importance. It has been proved beyond a doubt that in a fat body, the mass of flesh, the food, etc., being the same, the protein consump- tion is less than in a lean body. It is not, however, sim- ply the absolute quantity of fat, but rather its amount relatively to that of the flesh which is the important point. But not only is the proteia consumption less in a fat body, ceteris jaarilms, but the rapidity with which eqmli- brimn is reached after a change in the food is less. The following are the results of two experiments, A on a lean animal (dog), B on a fat one : Increase of meat in food. Grms. EqnUibrinni on Gain of flesh. Grms, Gain in per cent, of incrsEised food. A B 1,800 1,620 3d day. eth " 309 1,365 17 84 A smaller increase of protein in the food of the fat ani- mal caused both a relatively and absolutely greater gain of flesh, which also continued twice as long. !N^umerous other examples of the same effect might be adduced, were it ne- cessary. As a consequence of this fact, a gain of flesh can be made more readily by herbivora than by carnivora, since 134 MANUAL OF CATTLE-FEEDING, the former are, as is well known, much inclined to the lay- ing on of fat, and even when in medimn condition gener- ally contain relatively a much larger quantity of that sub- stance than the carnivora. For the same reason we may often increase disproportionately the amovmt of albumin- oids in the food of the herbivora without having to fear that it will all be converted into circulatory protein and rapidly consumed. Good results may often be attained in this way, but we should never, with these animals, leave out of account the bodily condition caused by the previous foddering. In the beginning of fattening, especially, the most appropriate fodder must be essentially different ac- cording to whether we have to do with lean and " run down " animals or with those which are already in good condition. Effect of Salt on Protein Consumption. — A mod- erate addition of salt to the fodder increases the circulation of the juices of the body, and consequently the protein con- sumption ; but the salt secures advantages, especially in the herbivora, which have already been spoken of. The feed- ing of salt is therefore especially in place when a greater energy of all the vital functions is desired, as in horses and well-fed working oxen, in young animals, and in male breeding animals, etc., while in fattening only so much should be given as is necessary to render the fodder sa- vory, and is demanded for the normal nourishment of the animal. Another action of salt is to increase the excretion of urine, often very considerably. This is observed especially when the animal is pre- vented from much drinking, either purposely or in any other way. For the excretion of larger quantities of salt, more water is necessary, and this is withdi'awn, in the first MANUAL OF CATTLE-rEEDIlTG. 135 place, from that excreted by evaporation through the lungs and skin, and, if -this is not sufficient, from the body itself. The live weight can tlierefore sink rapidly when large doses of salt and little water are given, while afterward, on the other hand, if more water is drunk, much of it may be laid up in the tissues, and the live-weight of the animal be again increased. Influence of Water on the Protein Consumption. —Giving too large quantities of salt to animals is to be avoided for still another reason, viz. : that the animals are led to drink large quantities of water, if they have access to it. This causes an increased protein consumption, that is, an increased destruction of valuable fodder materials, especially when the larger quantity of water is not retained in the tissues but is rapidly removed by an increased ex- cretion of urine. Experiments by Voit on fasting animals showed an ia- crease of the protein consumption in this way by as much as 25 per cent., and, according to observations by Henne- berg,* in Weende, on oxen, the increase of the protein consumption, when the amount of water was increased 22.4 per cent., averaged 5.8 per cent. Even the last named increase is by no means insignificant ; it amounts to a third, or perhaps even a half of the protein which otherwise might have been deposited in the body. In any case, in order to get the most advantageous results possible, espe- cially in the feeding of yoimg animals and in fattening, we must avoid everything which involves or leads to an excessive use of water ; e. g., too watery fodder, too high a temperature of the stall, too much salt, too much move- ment, etc. This is more especially to be observed in re- gard to sheep, since these animals di-ink voluntarily much *"NeueBeitj;age," etc., 1871, p. 397. 136 MANITAI. OP OATTLE-FEEDIlfG. less water in proportion to the dry matter of their fodder than cattle. In round numbers, the normal amount of water (in food and drink together) may be stated as 4 lbs. per pound of dry matter of the fodder for cattle, and haK that quantity for sheep. In milk-giving animals an increased consumption of water is less disadvantageous, and may indeed cause an increased milk-production ; but in this case, also, it is un- doubtedly advisable not to exceed a certain limit as to the proportion of water in the fodder. The Effect of Stimulants on the protein consumption seems to be inappreciable. The action on the nervous sys- tem seems to be caused by so minute a metamorphosis of albuminoid substance that it has no significance compared with the total protein consumption in the body. It is, however, another and as yet undecided question whether the increased nervous activity may not cause an increased consumption of fat in the body, as does muscular exer- tion, e. g. § 4. Feeding "wtth Fat ob Cakbhtdeates Aiomb. Fat alone does not decrease the Protein Con- sumption. — This is shown plainly by the following results obtained by Yoit * on a dog : arms. Grms. Grms. Grms. GnnB. Grme. Grms. Fat per day Flesh consnmption . 170 100 185 200 155 300 187 300 165 340 205 350 291 We see at once that even the largest rations of fat are not able to stop or decrease the loss of flesh from the ♦ Zeitaohrift f. Biologie, V., 329. MANUAL OP OATTLE-FEEDIN-a. 137 body, but seems rather to increase it slightly. This latter effect has been observed ia other experiments, and appears to be due to the influence of, the fat in drawing into cir- culation the organized protein of the body. It shows it- self still more markedly when, along with the fat, an amount of albuminoids not sufficient to balance the con- sumption is given. The effect is in every case small, and this action of fat is far more than counterbalanced by another which shows itself when it is fed along with a sufficient quantity of protein. Carbhydrates alone do not decrease the Protein Consumption any more than does fat. The same amount of protein is oxidized and destroyed in the body as in the complete absence of food. They differ from fat, however, in the fact that they do not, like the former, slightly in- crease the protein consumption. They are simply without effect on it when fed ^sdnisweby. § 5. Feeding with Pkotein and Fat. The Protein Consumption is determined chiefly by the Supply of it in the Pood, just as it is in feed- ing exclusively with albuminoids, and any increase in the amoimt of the latter causes a corresponding increase in thefornaer. Thus, Toit (Zoc. cit^ obtained the following results : Grms. GrmB. Grms. Grms, Grms. Grms. ( Fat 250 150 233 300 176 259 250 250 270 200 500 502 200 800 778 250 FoodJ (Meat 1,500 1,.381 Consninption of flesh per day 138 MANUAL OF CATTLE-FEEDING. It is evident that the protein consumption in the body is greater, the larger the amount of protein in the food. The increase, however, is not quite as great as it would have been without the fat ; for, other things being equal, Fat decreases the Protein Consumption, and tliere- fore increases the deposition of flesh in the body. This is most plainly shown if, after the body is in equilibrium with a certain quantity of albuminoids, fat be added to the food. The following example from Voit's researches illus- trates this fact : Food. Urea per day. GnuB. Flesh consump- Date. Meat. Grms. Fat. Grms. tion in body. Gnus. July 31 Aug. 1 " 3 " 3 1,000 1,000 1,000 1,000 100 300 81.7 74.5 69.3 81.3 1,140 1,043 970 1,134 While the animal, when fed with 1,000 grammes of meat, was losing daily about 140 grammes of flesh, the addition of 300 grammes of fat served not only to prevent this loss, but to cause a slight gain. This decrease of the protein consumption is not very considerable^ in a single day, amounting, in the dog used by Voit, to at most 168 grammes of flesh, or 45 grammes of dry protein, and varying from 1 to 15 per cent, of the total consumption. Its amount depends not only on the protein and fat of the food but also on the condition of the ani- mal. The greater the amoiint of circulatory protein in the body, and the less fat it contains, the more of the pro- MANUAL OP CAU'LE-FEEDING. 139 tein of the food is converted into circulatory protein and consumed. The Decrease of the Protein Consumption is no greater -with a large than vrith a small Ration of Albuminoids, if tLe quantity of fat remains the same. This, indeed, follows from the statements of the first paragraph. An increase of the albuminoids of the food causes more circulatory protein to be foimed, and, as a consequence, increases the consumption ; and while the . latter is less than it would be without the fat, the difference is not notably, if at all, greater than with the smaller amount of albuminoids. The addition of the fat simply makes the consimiption of protein less them it would he without it under the same ciTGumstcmces ; but this comparatively small decrease may sometimes make all the difference between a continual loss of flesh from the body and a state of equilibrium, or even a gain of flesh, and thus may be a most important factor in feeding, as illustrated in the experiments in the previous paragraph. A dog weighing 35 kilogrammes (Y7 lbs.), when fed ex- clusively on pure meat, needs about 1,500 grammes daily in order to remain in good condition and in equilibrium as regards nitrogen. If, instead of this, he receives only 500 grammes, he loses, for a number of days, about 150 grammes daily of his OAvn flesh ; and if, after a considera- ble time, he comes into equilibrium with the smaller ration, he is wasted away and in wretched condition. But if, along with the 500 grammes of meat, about 200 grammes of fat be given, this loss of flesh is speedily checked, and when the protein consumption has come into equilibrium with the supply the animal remains in a sound and well-nouiished condition. The addition of 200 140 MANUAL OF CATTLE-FEEDING. grammes of fat so decreases the protein consumption, which was before greater than the supply, causing the animal to lose flesh constantly, that it is now equal to the latter, or perhaps, in some cases, less, so that a gain of flesh results. That is, we can keep the same amount of flesh on such an animal by feeding 500 grammes of meat and 200 grammes of fat, as by feeding 1,600 grammes of pure meat. In the former case, although the supply of protein is much less, the consumption of it in the body is correspondingly less ; and though the animal may be less lively and ener- getic in its motions on this account, it may still be main- tained in good condition for any length of time on such a ration without the least injury to its health. That the protein consumption, as above stated, is less than when 1,500 grammes of meat are fed is due, in great part, to the decreased supply of albuminoids, the effect of this being the same as when only albuminoids are fed, as was ex- plained and illustrated in the flrst paragraph of this section. The effect of the addition of the fat is simply to de- crease the consumption a little more ; but this little carries it past the point of equilibrium, and so prevents the con- tinual loss of flesh which takes place without it. The animal may even gain flesh on such a ration. In this case, therefore, the addition of 200 grammes of fat has saved 1,000 grammes of meat, as compared with a purely flesh diet. We are not, however, to understand that if to the large ration of 1,500 grammes of meat we add 200 grammes of fat, the daily flesh consumption will sink at once to 500 grammes or less, and that 1,000 grammes of flesh will be formed in the body. The protein con- sumption, as already insisted on, is dependent in the first place on the supply of albuminoids in the food, and an in- crease of the latter correspondingly increases the former ; MANUAL OF CATTLE-FEEDING. 141 SO that, while a large quantity of protein would be daily consumed in the body with the large ration of albumin- oids, the gain of flesh would be no greater, and might be even less, than with the smaller ration. Fat may cause a long-continued Gain of Flesh. — "We have seen that any gain of flesh caused by an increase of the albuminoids of the food continues but a short time. The additional albmninoids increase chiefly the amoiuit of circulatory protein in the body and consequently the pro- tein consumption, and equilibrium between the food and the body is speedily established. If, however, the gain of flesh is caused by the addition of fat to the food, the case is different. The fat seems to favor the formation of tissue, i. e., of the more stable organized protein, which is less easily oxi- dized, and consequently, as is found by experiment, the gain of flesh caused in this way may continue for a com- paratively long time, so that although the saving of protein effected by the fat may not be gi-eat in a single day, the total result is very considerable. It has been already shovm (p. 133) that the fat deposited in the body has the same effect in this respect as that of the food. The Gain of Flesh continues much longer on a me- dium than on a large Ration of Albuminoids. — ^The following experiments (see page 142) illustrate this. The total gain up to the beginning of nitrogen equili- brium is seen to be in general no greater, and often less, with a large than with a. medium ration of albuminoids. In details exceptions are to be expected, since the experi- ments were not all made consecutively, and since not only the supply of food but the bodily condition has much to do with the gain of flesh. In order, then, to obtain as great and long-continued a 142 MANtJAIi OF CATTLE-FEEDING. Length of Experi- ment. Days. 32. 4 3. 3, 4. 10, 23. 7, 3. Food. Total gain of flesb, Grms. Fat. Grma. Meat. Grme. 350 500 1,794 300 800 320 250 1,000 875 250 1,250 294 250 1,500 476 150 1,500 104 30-150 1,500 889 250 1,800 854 250 2,000 352 Grain per day. GrmB. 56 80 125 98 119 10 38 122 117 Whether nitrogen equilibrium. Not yet. It Nearly. Quite. Nearly. Quite. Nearly. deposition of flesh in the body of a dog, e. g., as possible, we should not feed large quantities of meat with fat. The absolute quantity of albuminoids in the food does not determine the gain, but only the protein consumption. Neither is it the absolute quantity of fat that determines the gain, but the relation between the two, together with the bodily condition. This being the case, we should first endeavor to ascer- tain what ratio of albuminoids to fat gave the best results, and then, having compounded a ration in accordance with this, should endeavor to induce the animal to eat as much as possible of it. Two extremes ought to be equally avoided ; too much albuminoids would cause an unneces- sary protein consumption in the body, while if the ration contained an excess of fat, it might be impossible for the animal to eat enough of it to supply himself with the necessary amount of protein. MAITUAL OP CATTLE-FEEDING. 143 In the fodder of the herbivora the action of fat in de- creasing the protein consumption does not show itself so plainly, its action being masked by the presence of large quantities of carbhydrates, which, as we shall see, have an effect similar to that of fat. Moreover, the amoimt of fat in the fodder of the rumi- nants cannot safely exceed a certain easily-reached limit. Small quantities of fat exert in general a favorable influ- ence ; larger quantities, however, are often very injurious, causing disturbance of the digestion and an increasing lack of appetite. The different modifications of fat, however, behave very differently in this respect, and the fat of the food certainly deserves attention, especially in the feeding of young animals and in fattening, and likewise in case of horses, and in general whenever the fodder is rich in al- buminoids. § 6. Pkbdimg with Pbotein and Cabbhtdbatbs. The Carbhydrates aot analogously to Pat on the consumption of protein and its deposition in the body. Like it, they do not suspend the protein Consumption, which increases or decreases with the amount of protein in the food; like it, they decrease the protein con- sumption somewhat, but riot greatly; like it, tooj they enable an animal to subsist or even gain flesh on a much smaller quantity of albuminoids in its food than would suffice were the ration composed of pure protein- The action of the carbhydrates on the formation of flesh has been investigated both in carnivorous and herbivorous animals. In the previous sections we have been occupied exclu- sively with experiments on camivora, for the reason that 144 MANUAL OF CATTLE-FEEDING. it is practically impossible to feed herbivorous animals on pure protein or protein and fat ; but the general principles deduced fi'om the experiments on camivora are applicable also to herbivorous animals. In the present section we shall give special prominence to experiments on domestic herbivorous animals, and shall take occasion to point out, in passing, some confirmations of the results obtained on carnivora by Yoit and others. The ordinary fodder of herbivorous animals, leaving out of consideration, for the present, water and mineral matters, consists essentially of protein and carbhydrates with small quantities of fat. A large number of experiments on these animals have been made. As of especial importance for our present purpose may be mentioned those of Grouven,* at Sak- iniinde, and of Henneberg & Stohmann,f at "Weende, on oxen ; those of G. Kiihn & M. Fleischer, ■};. at Mockem, on milk cows ; and those of E. Schulze & M. Marcker, § in Weende, on sheep. Of these, the Weende experiments on oxen in particular are of the highest value, both for our present purpose and many others, having been executed in the most careful and thoroughly scientific manner. The Protein Consumption is Determined by the Supply in the Food. — The following experiments on oxen by Henneberg & Stohmann {he. cit.), in which the amount of protein in the food varies while that of the non-nitrogenous nutrients remains essentially the same, * Zweiter Salzmunde Berioht, 1864. t " Beitrage zur Begriindung einer Rationellen Fiittening der Wie- derkauer," 1864, and " Neue Beitrage," etc., 1871. :|:Landw. Versuchs-Stationen, ZII., 197 and 450. § Joumal fiix Landwiithachaft, 1870 and 1871. MANUAL OF CATTLE-FEEDING. 145 iilustrate this fact, which is shown also in all the other experiments cited. The non-nitrogenous matter of the food here includes the fat reduced to its equivalent of starch (p. 157) ; the numbers in the last three columns express dry protein (nitrogen x 6.25) and not fresh flesh. No. of Kcperiment. Non-nitroge- nons matter di- gested. LbB.* Protein di- gested. LbB. Protein consumption. Lbs. Gain of Protein. Lbs. 1860-1861. (17 10.23 1.50 1.00 0.50 18 10.10 2.06 1.43 0.63 (85 1460 2.50 2.12 0.38 26 1449 3.37 2.75 0.62 (21 1408 2.19 1.13 1.06 (20 13.73 3.00 1.81 1.19 1865. At. of 5 & 6. 11.60 0.84 0.86 -0.02 At. of 4,7 & 8. 11.95 2.52 1.99 0.53 These results show plainly that the addition of more protein to a fodder causes chiefly an increase in the circu- latory protein of the body, and to a far less degree a gain of flesh, and fully confirm the conclusions drawn from sim- ilar experiments on dogs. At the same time it is obvious that in these experiments there was a greater tendency to- ward the laying on of flesh than was the case in those on camivora ; a larger proportion of the total protein of the • Geiman pounds. 1 lb. German = 1.1 lb. aT. 7* ]46 MANtlAL OF OATTLE-FEEDINa. ration and of the added protein went to form organized protein. Some experiments on goats by Stolvmann,* which strik- ingly illustrate the influence of the supply on the protein consumption, may also be mentioned. The following table contains all the essential data : Date of Experi- ment, FODDEn PEB DAT. Protein di- gested per day, firms. Protein consump- tion t per day. firms. Gain of pro- H.y. Grms. Lineeed meal. Grms. tein per day. Grms. 1. May 23-29.. 1,500 100 111.6 66.6 1.9 2. June 6-13 . . 1,450 150 135.0 79.4 9.0 3. " 30-36.. 1,400 300 133,3 90.6 11.1 4. July 4-10... ; 1,350 350 150.9 90.1 33,4 5. " 35-31.. 1,350 350 170.5 101.6 18.3 6. Aug. 8-14 . . 1,100 500 193,8 117.9 37.4 7. "■ 23-28.. 950 650 331.4 143.1 30.6 8. Sept. 5-11.. 800 800 357.3 173.7 37.4 9. " 19-35.. 1,600a. 93.9 56.3 -4.4 10. Oct. 3-9.... 1,600J. 74,1 41.9 6.4 Nothing could be more evident than the dependence of the protein consumption on the supply in these experi- ments. We have seen that in a fasting dog the protein con- sumption is at once increased by even the smallest ration of meat. Some experiments by Grouven {loo. eit.) seem * " Biologisciie Studien," Heft 1, p. 131. f Exclusive of the protein contained in the milk, which varied but slightly. MANUAL OF CATTLE-FEEDING, 147 to indicate that the effect on the herbivora may be differ- ent. He observed that in full-grown oxen the protein con- sumption was decidexily less on a ration of rye-straw than during hunger, and that the addition of pure non-nitroge- nous nutrients to the straw decreased it still more. Ox No. L Fodder per day. Live weight. Lba Nitrogen digested. Grms. Oonsnmp^ tion of flesh. Grms. Loss otflesb. Qrms. 1,019 959 990 968 5.2 3.2 4.6 950, 475 250 230 625 8.71b8. straw 326 6.6 " +2.2 lbs. sugar. 6.5 '• +3.3 " 176 110 Ox No. II. 7iBl 1,109 360 250 640 6.6 lbs. straw 777 799 5.5 2.7 218 5.3 " +2.2 lbs. sugar. 191 5.3 " +3.3 " 781 3.0 395 320 Ox No. m. 1,150 1,155 0.5 1,427 771 1,525 9.2 lbs. straw, 757 The aacafAcy of these results is impaired by the facts that between the experimental periods the animals re- ceived an abimdant but not uniform fodder, and that the preliminary feeding was in each case so short (3 to 6 days) 148 MATTTJAL OF CATTLE-FEEDING. as to render it doubtful whether the effect of the new fod. der was fully established. Furthermore, the dung often contained almost as much, and sometimes even more nitrogen than the fodder, show- ing that the former contained considerable quantities of nitrogenous matters coming from the body. The result of this, of course, is that the numbers for digested pro- tein and for the consumption of flesh are too low; those for the loss of flesh (nitrogen of fodder less that of dung and urine), however, are unaffected by this source of error. If we are to accept this result of Grouven's as correct, we must ascribe it to the large quantities of non-nitrogen- ous matter which were digested along with the small amonnt of protein, and which would tend to diminish the protein consumption- This action of the carbhydrates is seen also in most of the experiments in which these sub- stances were added to the straw. Of somewhat the same nature as Grouven's results are those which show that addition of protein to a fodder poor in this substance may cause a considerable gain of flesh. The experiments by G. Klihn & M. Fleischer i^o. oit.), on cows, serve to illustrate this. Two cows were fed dur- ing a first period with hay, either alone or with the addi- tion of starch, and in a second period a nitrogenous bye- fodder was added. The hay used contained an unusually small quantity of protein (Nutr. ratio, 1 : 12), and a com- paratively small amount of it was consumed, so that the food in the first period was far from rich. Even the addi- tion of the nitrogenous bye-fodder in the second period did not mate it particularly so, but it nevertheless caused a considerable gain of flesh, which continued for some time. The experiments covered, including the preliminary MANUAL OF CATTLE-FEEDING. 149 feeding, from twenty-two to twenty-foirr days, and the gain in the last six days was fully equal to that at the be- ginning. The table shows the results obtained during the experiment proper (exclusive of the preliminary feeding), and also the protein consumption and the gain of protein for the last five days of the feeding with nitrogenous bye- fodder. Cow No. L Fodder. DIOEBIED put i>AY. Nutr. ratio 1: Protein conBump- tion per day. Grms. Gun Date. Protein. Grma. Oarbhy- drates. Grme. ot protein per day. Grms. Deo. 28-Jan. 6 . Hay 393 680 4,800 4,986 13.2 7.3 187 (343 1345 -6.9 Jan. 17-Feb. 1 1 " 27- " 1 ■• Hay and rape-cake + 124.7 +117.8 Cow No. n. Feb. 16-MJir. 3.... Mar. 12-27 I " 22-27(' Hay and Btarch. . . 394 6,550 14.1 166 Hay and beans 728 5,B70 7.6 j.saa 1332 + 40.0 +182.2 +181.9 The addition of protein to a ration poor in this sub- stance caused a considerable gain of flesh by the animals. At the same time, it did not fail to affect the protein con- sumption, approximately doubling it in each case. We conclude, then, that in the case of the herbivora protein added to a ration does not pass so promptly and com- pletely into circulatory protein as it does in the camivora, but may cause a considerable gain of flesh. This inclina- tion toward the formation of organized rather than circu- latory protein seems to be a characteristic of the herbivora, perhaps due in part to the large amounts of non-nitrogen- ous food which they consume and in part to the consider- 150 MANUAL OF OATTI-E-FEEDING. able quantities of fat usually laid up in their bodies, and is a circumstance favorable to economy in feeding. But though increasing the proportion of protein in a ration may cause a gain of flesh, the experiments by Stoh- mann, already cited, show that when the food is already rich in this substance the gain is much smaller and is accompanied by a greatly increased protein consump- tion. Carbhydrates decrease the Protein Consumption. — ^The following experiments by Voit * on a dog show that Food. Flesh Date ot Experiment. Meat. Grms. CarbhyclrateB. Grms. conBumptiou. Grms. June 23-July 2, 1859 Jnlv 2-5. 1859 500 500 300-100 503 564 July 4-10,1804 800 800 800 100-400 826 " 10-19, " 763 " 19-20, " 895 July 23-36, 1864 1,000 1,000 1,000 100-400 1,028 " 36-28, " 903 " 28-Aug. 1, 1864 ■ 1,113 June29^uly 8,1863 July 8- " 13, " 1,500 1,500 200 1,599 1,454 Jan. 6, 1859 2,000 3,000 200-300 1,991 " 7-11,1859 1,792 * Zeitschrift f. Biologie, V.. 434. MAlTirAL OF CATTLE-FEEDING. 161 the carbhydrates exert the same influence on the protein consumption as does fat, viz. : render it less than it other- wise would be. In almost every case the effect of the addition of carb' hydrates was not only to decrease the protein consumption but to render it less than the supply, and thus to cause a gain of flesh instead of the loss which had been taking place. The action of the carbhydrates in decreasing the protein consumption is also to be seen in experiments on herbivora, though in these it is seldom so sharply expressed as in the results just given, because these animals, in any case, receive large amounts of carbhydrates and the effect of a further addition is therefore comparatively small. Grouven's experiments show plainly the decrease of the protein consumption caused by the addition of sugar, even to straw fodder, which of itself contains much carb- hydrates and little protein. Some of Henneberg & Stohmann's experiments in 1865 also show this action of the carbhydrates. The quantities are per day and head. a. Fodder Eich in Pkoteih. ' Protein digested. Founds. Ciirbhy- drates and fat digested. Founds. Nutritive ratio. ■ Protein consump- tion. Founds. Gain of protein, Poundfl. Ox II, Experiment 7. . . " " 8... 2.60 3.51 , 10.95 13.51 1 :4.2 1:5.0 2.14 1.83 0.46 0.68 152 MANUAL OF CATTLE-FEEDINO. 6. FoDDEB PooK m Pbotbin. Protein digested. Founds. Carbhy- drates and fat digested. Pounds. Nutritive ratio. Protein consump- tion. Pounds. Gain of protein. Oil. Experiment 3. . . 0.83 7.33 1: 8.8 0.83 -0.01 It 1... 0.78 9.99 1 : 12.8 0.78 0.00 Oxn. " 5... 0.89 11.08 1 : 12.4 0.97 -0.08 " " 6. . . 0.78 13.13 1 : 15.6 0.74 +0.04 Here, again, an increase of the earbhydrates, though accompanied by a slight decrease of the protein, changed a loss of flesh into a gain, as weU as diminished the pro- tein consumption. Further confirmation of this effect of the earbhydrates is found in the frequently observed fact that in the great majority of cases where the supply of albuminoids is suf- ficient to cause any production of flesh, the greatest rdalme gain is produced by rations having a wide nutritive ratio, that is, a large proportion of earbhydrates to albumin- oids. This fact is well shown by the following selection from the experiments of Schulze and Marcker {he. cit.) on sheep, which are arranged according to the nutritive ratio. They were not all made on the same animal, nor at the same time, and are only comparable in a'general way ; but, being toler- ably numerous, they are sufficient to illustrate our present point. The results are per day and head. The protein in the daily growth of wool, amounting to about five grammes is not included in the gain of protein. MANTJAL OF CATTLE-FEEDING, 163 Ko. of EzpeTiment. Protein digested. Orammea, Nutntive ratio. Protein consumpt^n. Grammes. Oainot protein. Grammes. Gain in per ct. of amt. digested. Experimeat 6... . 30.6 1 : 17.4 24.8 1.4 4.6 Experiment 13 " 3.... " 11.... " 2.... ' " 10.... 8.... 67.9 59.5 68.1 69.7 72.5 85.8 1 :9.4 1:8.9 1 :a6 1:8.6 1:8.1 1:7.7 54.8 45.9 56.2 49,1 54.7 63.6 8.0 9.0 6.8 5.5 .1.2.7 1?.3 11.8 15.1 • 10.0 9.2 17.5 20.1 Average 14.0 Experimmt 7 9.... 17.... 116.8 156.6 248.3 1:4.9 1:3.7 1 :2.8 96.0 142.5 237.6 15.9 9.0 6.1 13.7 5.8 2.5 Aveia^ 7.3 The very wide nutritive ratio of Experiment 6 caused only a very small gain, because the absolute amount of protein was very small, but that any gain at all was made is doubtless due to the decrease of the protein consump- tion by the large amount of carbhydrates. The other experiments show in general that a larger proportion of the protein of the food is applied to the pro- duction of flesh when the food has a medium nutritive ratio than when it has a very narrow one. In detail, ex- ceptions are to be expected, since, as above stated, the experiments were not all made at the same time and the bodily condition has much to do with the effect of a ration. Stohmann's experiments on goats, already described (p. 146), also illustrate the advantage of a medium nutri- tive ratio, as the following table shows : 154 MANUAL OF CATTLE-FEEDmO, Protein digested per day. Grms. NntritlTe ratio. Gain of protein per day. Qtbu. Gain in per cent. of digested protein. 1 111.6 125.6 133.2 150,9 170.5 193.8 221.4 257.2 5.87 5.42 5.08 4.78 4.22 3.27 2.84 2.55 1.9 9 11.1 23.4 18.3 27.4 30.6 27.4 1.8 a 8 7.3 8.3 4. ., 15.9 6 10.6 6 14.3 7 14.0 8 10.9 The relalme gain of protein increased up to a nutritive ratio of 1 : 4.78, and then decreased. These and many other experiments which might be ad- duced show that a larger proportion of the digestible pro- tein of a ration is applied to productive purposes when that ration also contains abundance of non-nitrogenous nutrients. "We must beware, however, of hastily concluding that a wide nutritive ratio is the most profitable for the pro- duction of flesh. The amount of fodder which an animal can consume is limited, and, if the nutritive ratio be made very wide, the absolute amount of protein in the quantity of food daily eaten will be insufficient to supply material for production. Moreover, the actual number of pounds of flesh gained per day is often greater on a ration pretty rich in albumi- noids, as, for example, in the experiments on sheep and goats just cited, though, of course, accompanied by a large protein consumption in the body. The, best pecuniary results may, MANUAL OP CATTLE-l'EEDING. 155' ilnder some cireumstances, be reached by a ration having a rather narrow nutritive ratio and pi'oducing a ra/pid gain of flesh, even at the expense of an increased protein con- sumption; whUe, under other circumstances, a wider nutritive ratio and a slower and more economical produc- tion might be more remunerative. Extremes in either direction, however, are likely to be unprofitable. Carbhydrates may cause a long-continued Gain of Flesh. — ^We saw in the previous section that a fodder of protein and fat could, under proper conditions, cause a long-continued gain, of flesh, while the gain caused by an increase of the protein of the food was usually only tem- porary. The same fact is true of feeding with prot.ein and carbhydrates. It is to be remembered, however, that the fodder of oiu* domestic animals always contains considerable quantities of carbhydrates, and that, consequently, the effects of a change from one method of feeding to another are not so sharply manifested as in the earnivora. To this is to be added that the digestive process lasts a considerable time in the herbivora, so that remnants of the old fodder may be resorbed along with the first portions of the new, and thus the change of fodder be made in reality a gradual one. In general the gain of flesh produced by a ration con- taining much carbhydrates continues for a considerable length of time, while that caused by a ration poor in these substances but rich in protein, although it may be 'greater at first, does not continue as long For example, in the experiments of Kiihn & Fleischer on cows (p. 149) the addition of protein to a ration con- taining much carbhydrates caused a gain of flesh which continued with but little decrease throughout the experi- ment and would doubtless have lasted some time longer, a 156 MANTJAI. OP CATTLE-FEEDING. result evidently due to the abundance of non-nitrogenou8 nutrients and their influence in decreasing the protein consumption. The experiments of Schulze & Marcker (p. 153), on the other hand, furnish a good /example of the opposite effect. In Experiment 6 the fodder consisted of hay and starch ; in Experiment 7, of hay and beans. The quantities of digested nutrients per day and head were : Protein. Grms. Carbhy- drates. G-rms. Nntritivo ratio. Ezpeiiment 6. 30.6 116.8 536,7 570.5 1 : 17.4 1: 4.9 Both experiments were on the same two sheep, and the results given are the average of those obtained from both The following table shows the protein consump- amma tion and the gain of protein by the body for the last day of the hay and starch fodder, and also for several days on the new ration : April 3. " 3 (new fodder). " 4.. " 5. " 6 " 7 " 14........ " 21 Protein consumptioD. Grms. Gain at protein.* Grms. 22.6 3.0 48.8 63.0 76.8 35.0 87.6 24.2 88.0 23.8 89.8 22.0 93.8 19.0 103.3 9.5 • Exclusive of growth of wool. HANTTAL OF CATTLE-FEEDING. 157 Here the change from a poor ration to one rich in pro- tein caused at first a very decided gain of flesh, but one that rapidly decreased, sinking to about a third of its original amount in less than a week and nearly disappear- ing in nineteen days. The contrast between this result and that obtained by Kiihn & Fleischer is exceedingly instructive, and shows anew the importance of a proper proportion of carbhy- drates and fat in the food for the economical production of flesh. Carbhydrates eqiiivalent to Fat. — ^It is an impor- tant fact for the theory of fieeding that the decrease in the protein consumption caused by a given quantity of a carbhy- drate is at least equal to, and generally a little greater than that caused by an equal weight of fat. Formerly, when all the non-nitrogenous substances of the food were supposed to be chiefly valuable as fuel to maintain the vital heat of the body, the relative value of fat and the carbhydrates was naturally measured by the amount of heat which equal weights of the two produced when burned ; and it being calculated that one pound of fat produced about 2.5 times as much heat as one pound of sugar or starch, it was assumed that the fat of the food was 2.5 times as valuable as the carbhydrates, and their so-called respiration equivalents were respectively 2.5 and 1. "So far as they serve for the production of heat, these numbers may represent their relative value, but, as we have seen, they have other important functions ; they not only favor the formation of flesh, but also, as we shall learn, of fat. For the former purpose they are fuUy equal, weight for weight, to fat, and for the latter much more nearly so than is shown by their respiration equivalents. 158 MANUAL OF CATTLE-FEEDING. The importance of this in the feeding of domestic ani- mals is evident. Fodders containing much fat are com- paratively costly, and not only that, but are difficult of digestion by herbivorous animals, and an undue amount of them is liable to produce injurious effects. On the other hand, the carbhydrates are cheap, are contained in large proportions in all the common fodders,, and are readily consumed and digested by the herbivora. These substances in the food of the herbivora effect what the fat does in that of the camivora : they decrease the protein consumption, and enable the animal to subsist on a much smaller quantity of the costly albuminoids than would otherwise be necessary. It is owing chiefly to the large quantities of them consumed by our domestic animals that they need comparatively little protein when fed for maintenance, and that when fed for production a part of the digested protein is readily deposited in the body as organized protein. § 7. Nutritive Vai,ue op AMmss. We saw in Chapter II. that a part of the nitrogenous matter of many feeding-stuffs is not true protein, but con- sists of various bodies, most of which appear to belong to the so-called amide compounds. It becomes, therefore, im- portant to consider the nutritive value of these substances, and all the more important because, until very recently, they have not been considered, or even recognized, in the analysis of feeding-stuffs, and since in many feeding experiments, from whose results important conclusions have been drawn as to the amounts of the various nutrients required in the food of farm animals, feeding-stuffs have been used which MANUAL OF OATTLE-FEEDING, 159 have since been sliown to contain not inconsiderable amounts of these bodies. If, as some writers have assumed, they have no nutri- tive value, we must conclude that our domestic animals require considerably less true protein in their food than has been hitherto thought, while if they have a value in feeding, it is important to know what it is. We shall con- fine our attention -here to the amides, since these are the only non-albuminoid nitrogenous matters which have been experimented on, and the only ones which have yet been found abundantly in the common feeding-stuffs. It may safely be assiimed that these comparatively sim- ple bodies caimot perform aU the functions of the albumin- oids, but it would seem that certain authors have allowed themselves to be carried too far by purely speculative con- siderations when they have pronounced them valueless for animal nutrition. . • Amides are Decomposed in the Body.— It has been shown by several investigators that amides introduced into the stomach are resorbed, and take part in the chemical changes in the body^ Schultzen & I^encki* appear to have been the first to experiment in this direction. They fed a dog, weighing about 16 lbs., with a fixed amount of bread, milk, and water lintil equilibrium was established between the supply and excretion of nitrogen, and then added to the foodVarious amides. They experimented- on acetamide, glycocol, leucin, and' tyrosin, and foimd that all except the first piroduced a decided increase in the excretion of urea. Aceta;mide appeared to pass through the system unaltered. With glycocol the following results were obtained : • ZeitBchrift fur Biologie,' VIII., 124. 160 MANUAL OF CATTLE-FEEDING. Date. Food. Urea per day. GrmB. Septembei 34 Bread, milk, and water. Same -1- 15 grms. glyooool. ^t It n Bread, milk, and water. (( (( <( (( It (( 3.960 25 3.768 26 7.187 27 9.470 28 3.810 29 3.780 The feeding of glycocol on the 25th and 26th caused a marked increase in the excretion of urea on the 26th and 27th, showing beyond a doubt that glycocol is con- verted into urea. No glycocol was found in the urine. The average excretion of urea on the days preceding the glycocol feeding was 3.8285 grammes per day. Total urea on 26th and 27th 16. 657 grms. Urea of two average days 7.657 " Excess caused by 30 grms. glycocol. 9.000 " Urea equivalent to" " " 11.970 " Difference 2.970 " =24.8peroent. It win be seen that nearly 25 per cent, of the glycocol fed is unaccounted for. The authors state that the glyco- col was not absolutely dry and pure, but it is difficult to imagine that so large an error could be thus caused. It seems more reasonable to suppose that rmder the in- fluence of the glycocol a gain of flesh took place, and this supposition is perhaps supported by the fact that the in- crease in the excretion of urea does not appear till the sec- ond day. It would seem as if a gain of flesh took place at first, and that subsequently the protein consumption in- creased, to fall again wlien the glycocol was withdrawn. MANUAL OF CATTLE-FEEDING. 161 Snch experiments as this, however, are not adapted, as they were not intended, to show the nutritive effect of the substance experimented on. We have seen that in the dog the addition of protein to the previous food causes but a temporary gain of flesh, while the " protein consumption " is permanently increased, and we should expect that, if amides aided in any way the production of flesh, the effect of a sudden addition of them to the food would be much the same. In an experiment continued for so short a time as this was, the nutritive effect must of necessity be transitory and hard to isolate. At the same time, the above results do not negative the belief that amides are of value as food. The experiment with leucin gave essentially the same results as the one on glycocol. The leucin was prepared from horn, and was not perfectly pure or dry. Date. Food. Urea per day. Unas. October 4 Bread, milk, and water. Same, + 10 grms. leucin. " +30 " " Bread, milk, and water. 11 11 11 11 i( 11 11 11 4.979 5.045 6 660 5. 6 7. 9 098 8 4 380 9 3.986 The average excretion of urea for the days preceding the feeding with leucin was 4.585 grammes per day. Total urea on 6th and 7th 15.758 grammes. Urea of two average days 9.170 " Excess caused by 40 grammes leucin 6.588 " Urea equivalent to " " " 9.000 «' DifEerence (=26.8 per cent.). . . . .... 8.413 " 162 MANUAL OF CATTLE-FEEDING. An experiment on tyrosin showed that a part of this sub' stance was converted into urea, but that a considerable por- tion escaped digestion. Similar experiments by v. Knieriem* on asparaginic acid and asparagin, gave similar results. They showed that these bodies are converted into urea in the animal body, and gave also a deficit of nitrogen, thougli a smaller one, amounting to 9 to 10 per cent, of the amide nitrogen fed. Further experiments by the same author f on hens, with asparagin, asparaginic acid, glycocol, and leucin, gave also the same result, though with a still smaller deficit of nitrogen. In no case, however, was the excretion in ex- cess of the supply in the food. Indications of Nutritive Value. — All these results, while highly interesting, leave the question of the nutri- tive value of amides still in doubt. There are many facts, however, which indicate that they may have a certain value as food. The very fact that they are decomposed in the body is one. Another is, that they are formed from the albuminoids of the food, to a considerable extent, by the action of the trypsin of the pancreatic juice in digestion. It seems hardly probable that .the amides thus formed are to be regarded as waste products. Moreover, we have seen that in the plant these bodies may serve as sources of pro- tein, and while such synthetic processes are particularly characteristic of vegetable life, they are by no means ex- cluded in the animal organism. That, under certain circumstances, an amide may have a high nutritive value, has been strildngly shown by Her- mann. It had been shown by Voit and others that gela- tin and similar bodies, belonging to the gelatigenous gronp • Zeitschrift fiir Biologie, X., 279. flbid., XIII., 36. MANUAL OP CATTLE-FEEDING. 163 of compovmds (p. 18), are capable of performing the func- tions of circulatory protein, but cannot serve as a source of organized protein. It was known also that when these bodies were decom- posed by acids they yielded essentially the same products as the albuminoids, except that the amide tyrosin was al- ways lacking. Escher,* under Hermann's direction, tried the experiment of feeding a dog with gelatin and tyrosin, and found that the two together could sustain life and cause a production of flesh. The very probable conjecture has been advanced, that amides in the food may play the same part that gelatin has been shown to do by Yoit, viz., take the place of a por- tion of the circulatory protein, thus leaving the latter avail- able for the formation of flesh or for other productive pur- poses, and this view seems to be sustained by the experi- ments about to be described. AspaJragin a Nutrient. — The only experiments as yet executed with the direct purpose of determining the food-value of amides are those of Weiske, Schrodt, and v. Dangeljf at the Proskau Experiment Station, on aspara- gin. A series of experiments on rabbits and another on hens having shown only that albuminoids could not be entirely replaced by asparagin, but giving in other respects indecisive results, a third series was made on two merino- southdown sheep. The plan of the investigation was as follows : The animals were fed at first with a fodder poor in protein (consisting of hfiy, starch, and sugar) until the excretion of nitrogen in the iirine became constant, and the gain of flesh on this ration was determined. Then, in three following periods, the amount of nitrogen in the daily ration * VierteljahrsBohrlft der naturf. (Jes. in Zuiich, XSI,, 36. f Zeitschrift fiir Biologie, XV., 261. 164 MANUAL OF CATTLE-FEEDING. was doubled by the addition respectively of protein (in the form of peas), gelatin, and asparagin, while the amount of non-nitrogenous nutrients remained practically the same. These additions to the original fodder were made in the opposite order in the two cases, in order that the nutritive effect of the asparagin in each sheep might be compared with that of protein in the other, and the influence of in- dividual peculiarities be thus eliminated. The preliminary feeding was continued in each period untn the excretion of nitrogen became constant, and the excrements then collected for five days and analyzed. In the statement of the results which f oUows, the average per day and head of these five days is given. Period L Bation : Sheep I. and II. , 500 grms. hay, 300 grms. starch, 50 grms. sugar. Protein digested. Grms. Carbbydrates digested. Grms. Pat digested. Grms. Nitrogen in urine. Grms. Gain of protein. Grms. Sheep I. . " II. 33.31 23.86 413.37 413.71 ■ 9.89 9.67 3.275 3.388 1.744 0.094 Pbkiod II. Bation : Sheep I., 500 grms. hay, 200 grms. starch, 50 grms. sngar, 48 grms. asparagin; Sheep II., 500 grms. hay, 80 grms. starch, 30 grms. sugar, 350 grms. peas. Protein * digested. . Grms. Carbbydrates digested. Grms. Pat digested. Grms. Nitrogen in urine. Grms. Gain of protein. Grms. Sheep I. . » n. 70.86 83.54 411.35 437.49 9.87 14.08 9.958 11.099 8.625 15.169 * Bee Note on opposite page. MANUAL OF OATTLE-FBEDING. Pkbiod III. 165 Bation : Sheep I. and U., 500 gxms. hay, 200 grms. staich, 50 gnus. Bugar, 53 grms. gelatin. Protein* digasted. Grms. Carbhydrates digented. Grms. Fat digasted. Grma. Nitrogen ia urine. Grms. Gain of protein. Grms. Sheep I.. " II. 66.68 66.38 399.71 401.52 9.23 8.86 8.69 9.95 12.375 4.250 Pkbiod IV. Bation: Sheep I., 500 gims. hay, 115 grms. starch, 15 grms. sugar, 200 grms. peas ; Sheep 11., 500 grms. hay, 200 grms. starch, 50 grms. sngar, 53 grms. asparagin. Protein* . digested. Grms. Carbhydpates digested. Grms. Fat digested. Grms. Nitro^n in nrine. Grms. Gain ot protein. Grma. Sheep I. . " n. 71.24 84.03 441.17 424.03 13.34- 9.77 9.730 11.497 10.435 12.175 Determinations of sulphur were made in all the experi- ments, and showed that in every case but one (Sheep 11. in Period III.) a gain of this element also took place. These results show, beyond all reasonable doubt, that as- paragin, at least, is really a nutrient, and that when added to a fodder poor in albuminoids it may cause a gain of protein by the body, just as we have already seen that the albuminoids may. It probably acts in the way already suggested, viz., by taking the place of a part of the circulatory protein and * ^o render the results hetter comparable, the nitrogen of the as< paragia and gelatin has in all cases been multiplied by 6.25 and counted as protein. 166 MANUAL OP CATTLE-FEEDING. protecting it from destruction. That this is so is perhaps indicated by the fact that a gain of sulphnr also took place. All the albuminoids contain this element, while asparagin :a free from it, and hence we may conclude that the pro- tein deposited in the body was derived from the albu- minoids of the food, and was not formed by a synthetical process from the asparagin. An important point is that the gain produced. by as- paragin was nearly as great as that produced by an equira- lent amount of albuminoids. From this it would appear that while asparagin cannot alone supply material for the formation of protein in the body, it is fully capable of performing the functions of the so-called circulatory pro- tein, so far as the production of flesh is concerned, and for this purpose is. practically just as valuable as protein for increasing the richness of a ration already containing a reasonable amount of that substance. This suggests the question whether much of the so-called circulatory protein of the body may not be simply that portion of the protein of the food which is converted into amides by the action of trypsin and other ferments during digestion. The sup- position seems quite plausible, and is certainly interesting from a physiological standpoint, though of little practical importance for the purposes of cattle-feeding. Other Amides. — Whether what Weiske has shown re- garding asparagin is true of other amides as well, can, of course, be finally decided only by direct experiment ; but in the meantime, while we must beware of drawing too general conclusions from a single experiment, it seems highly probable that at least those other amides which have been shown to be convertible into urea in the body may contribute to nourish it. But, if this be true, it also follows that these bodies as MANUAL OF CATTLE- FEEDING. 167 they occur in fodders, *". e., associated with comparatively large quantities of protein, are practically just as valuable for the production of flesh as the lattei", since, when feed- ing-stuffs containing them are used, we have essentially the conditions of Weiske's experiments, viz., amides added to a fodder containing considerable true protein, and should expect the same results. The importance of this fact is easily seen. If, for practical purposes, amides are equivalent to protein, it is unnecessary to consider them separately in the formation of feeding standards, while substitution of a part of the protein called for by a feed- ing standard by amides will cause no decrease in the nu- tritive value of a ration, sofa/r as the ppoduction of flesh is concerned. None of the experiments yet made touch the question of the effect of amides on fat production. It Doay well be the case that they cannot play the important part in this process which the albuminoids appear to, and, on the other hand, it is quite possible that they, like the carbhydrates, may protect the fat of the body from oxidation. Speculation in advance of expieriment is fruitless; but, meanwhile, though the study of the nutritive value of these bodies has but just begun, all the results yet reached warn us against hastily declaring them worthless or the results of chemical analysis of feeding-stuffs false and mis- leading. § 8. Effect of Quastitt of Food. A Iiarge Amount of Fodder Causes a Relatively- Larger Gain. — It is self-evident that a large quantity of fodder of the same composition must cause a greater depo- sition of flesh in the body than a small one ; but the gain is not only absolutely, but relatively greater, as is shown 168 MANUAL OF CATTLE-PEEDINa. by numerous experiments made on oxen, at Weende, by Heniieberg & 8tolimann. In one case, e. g., tlie total quantity of the digestible nutrients in the daily fodder was increased from 17.86 to 19.46 pounds, while the ratio be- tween the digestible albuminoids and the non-nitrogenous nutrients (the nutritive ratio) remained the same. The result was that, after the increase, 32 per cent, of the total quantity of digested albuminoids was deposited as flesh, while before only 18 per cent, had been. The absolute quantities were 1.19 and 0.62 pounds. In other trials, on a ration consisting exclusively of clover-hay, an increase of fom* or five pounds per day and head in the hay ration caused the amount of protein deposited as flesh to increase from 9 per cent, to 14 per cent., and in another experiment from 11 per cent, to 15 per cent, of the total digested protein of the fodder. That is, out of every hun- dred pounds of digested protein the animals converted into flesh, on the smaller ration, 9 and 11 pounds, on the larger, 14 and 16 pounds. These facts show how exceed- ingly important it is, especially in fattening, to stimulate the animals to the largest possible consumption of fodder consistent with health ; a little more or less may produce an essentially different effect, showuig itself perceptibly in a more or less rapid increase of the live weight. CHAPTEE Vn. THE FORMATION OF PAT. § 1. SomiCES OF Fat. The Pat of the Food, when digested and resorbed, may remain nndestroyed under suitable conditions, and be stored up in the body ; this is no^ as certain as that a for- mation of fat from other constituents of the food may also take place, "We will, on this point, only refer to the re- sults of some of the later experiments, which, like many on the laws of flesh formation, we owe to the activity of the Physiological Institute at Munich. Carnivorous animals which, by a previous feeding with meat exclusively, have become rich in flesh and compara- tively poor in fat, can be easily made quite fat-free by long fasting ; the time when the minimum of fat remains is easily recognized from the fact that the excretion of urea, which' during hunger is very constant, at last in- creases quite suddenly, because with the entire disappear- ance of the fat more protein is consumed in the body.. Such an animal, a dog weighing about 20 kilogrammes, after thirty days of fasting, was fed for five days with the greatest possible quantities of pure fat, of which, on an average, 370.8 grammes daily were digested. This is such a large quantity that it is impossible to suppose it to have been completely oxidized in the body, for then 1,040 grammes of carbonic acid should have been excreted 8 170 MANUAL OF CATTLE-FEEDING. daily, while direct determinations of the respiratory pro- ducts of dogs twice as large and in the best condition give much smaller numbers. In the body of the animal, which was killed at the end of the experiment, 1,352.Y grammes of fat were found on the various organs, instead of the 150 grammes which, ac- cording to other investigations, was the greatest amount that could have been present in the body after thirty days' fasting, so that in this case about 260 grammes daily of the fat of the food remained undestroyed and were de- posited in the body. In numerous other experiments on dogs, too, with a more normal food of meat and fat, and with help of the respiration apparatus, the fact has been confirmed that often a very considerable part of the fat of the food may be retained in the body. The fat, however, must be analogous to the animal fats or easily altered into them, since entirely foreign fats are either not resorbed from the alimentary canal at all or are rapidly oxidized. This does not, of course, prevent the fat in the fodder of the herbivora from contidbuting di- rectly to the deposition of fat in the body, since most of the vegetable fats are very similar in their composition and properties to the animal fats. Formation of Fat in the Body. — For the fact of the formation of fat in the body from other siibstances no special proofs need be adduced ; it is sufficiently evi- dent from daily experience, especially in fattening and in mUk-production. But it is of importance to consider the question what nutrients yield chieiiy or exclusively the necessary mate- rial for the formation of fat. Naturally only the albuminoids and carbhydrates are to be considered in this connection, for besides these nutri- MANUAL OF CATTLE-FEEDING. 171 ents and the fat itself, there are no other organic substan- ces present in such quantity in the fodder, either of the herbivora or camivora, as to be able to contribute, in any essential degree, to fat-formation. Formation of Fat from Albuminoids. — That fat can be formed from the albuminoids is now denied by no one acquainted with the subject. The fact that the albmninoids in decay, and on treat- ment with alkalies and with oxidizing agents, form vari- ous fatty substances along with other products of decom- position, favors this view: It has also been observed, that in the milk of the same cow the quantity of albuminoids frequently decreases when that of the fat increases, and the reverse. The occasionally observed formation of so- called adipocere also favors this view ; almost all the nitro- genous substances of the body disappear, and in place of the muscles, etc., appears a waxy-looking, fatty mass, solu- ble in ether. ' Somewhat similar is the fatty degeneration of the muscles and other organs of the living body in cer- tain diseases and not seldom in excessive fattening, of swinCj e. g. This fatty degeneration of almost all the or- gans of the body is especially marked in phosphorus pois- oning, and, according to observations made in Munich, it cannot be doubted that fat in this case arises exclusively from the albuminoids, urea being separated from the latter and excreted. Two apparently independent alterations of the tissue metamorphosis appear to occur at the same time ; first, an increased protein consumption, resulting in the pro- duction of urea and fat, and second, a diminished absorption of oxygen by the blood and consequently a decreased oxi- dation of the fat, both processes working together to cause a large deposition of fat in the body. For example, the liver of a man who died of phosphorus poisoning con- 172 MANUAL OP CATTLE-]pEEDING. tained m its dry substance the enormous amount of 76.8 per cent, of fat. If a doubt still remained as to the f onnation of fat from albuminoids, it must disappear on a consideration of the results which have been obtained on healthy animals with an entirely normal food. For example, the eggs of ordi- nary flies have been allowed to develop on pure blood and from seven to eleven times as much fat found in the larvae as was originally contained in eggs and blood together, although the animals had not consumed nearly aU the blood ; the excess of fat could Qnly have come from the albuminoids of the food. Yet more important, however, are the numerous experi- ments made by feeding dogs on large quantities of pure (fat-free) meat. The three following experiments by Ypit & Pettenko- f er * may serve as an example. In these experiments the respiration apparatus was used, and hence the excretion of carbon, as well as of nitrogen, could be determined : Fifth day of feeding with 1,800 gnns. meat. Second day of feed- ing with 2,500 grme. meat. Pirst day of feeding with 2,000 grms. meat. Nitrogen. Grme. Carbon. Grms. Nitrogen. Grnjs. Carbon. Grms. Nitrogen. Grms. Carbon. Grms. Fed 61.20 59.10 0.60 B9.70 835.4 35.6 4.3 179.0 2ia9 85.00 84.38 1.00 85.38 3iao 60.6 6.7 213.6 270.9 68.0 66.5 0.8 67.3 250.4 Excreted in Urine Dnng Beapiiation.. Total excretion 40.0 5.4 158.8 208.7 Gain (+) or Lobs (-). +1.B0 +6.5 -0.38 +42.1 +0.7 +46.7 * ZeitBohrift f. Biologie, VII., 433. MAITUAL OF CATTLE-FEEDING. 173 Iq the second and third experiments especially, -while there is no essential gain or loss of nitrogen, there is a gain of carbon by the body larger than any possible ex- perimental error, and which must be interpreted, accord- ing to the principles of Chapter Y., as showing a produc- tion of fat in the body, and that this fat must have been produced from albuminoids is self-evident. In the first experiment the feeding had continued four days, and there the gain of carbon is small, indicating that a gain of fat produced by albuminoids alone does not continue long, a fact which other results confirm. Many other similar ex- periments showing a formation of fat from albuminoids might be adduced. Fat feom Caebhydeates. — ^Whether fat can be formed from carbhydrates is still a disputed question. Accord- ing to Yoit & Pettenkofer the protein of the body in de- composing takes up the elements of water and splits up into urea and a fat-like substance ; and, as stated on page 88, it has been calculated that 100 parts of protein and 12.3 parts of water, contain the elements of 33.5 parts of urea, 2Y.4 parts of carbonic acid, and 61.4 parts of fat. They have shown, in experiments shortly to be de- scribed, that the carbhydrates of the food are more easily oxidized in the system than the fat of the food or the fat formed from the albuminoids, and that they protect the lat- ter two from oxidation and thus indirectly aid the forma- tion of fat. Having also shown, by experiments like those just adduced, the possibility of the production of fat from protein, they naturally regard the latter, together with the fat of the food, as the chief sources of fat under all cir- cumstances, and consider the action of the carbhydrates to be simply protective. According to this view the carbhydrates would, at most, 174 MANUAT^ OP CATTLE-FEEDING. serve for the production of fat only when the protein and fat of the food were exhausted, or, in other words, when the supply of oxygen in the body was not sufficient to con- sume all the carbhydrates. If we find that, in aU experi- ments on fattening, the digestible protein and fat of the food are sufficient to account for the amount of flesh and fat actually produced, we shall have very strong presump- tive evidence that the views of Yoit & Pettenkofer and their followers are correct, though, of course, such evi- dence is of a negative character and can never reach abso- lute proof. If, on the other hand, we find that, in ac- curately conducted experiments, the digestible protein and fat of the food do not suffice to account for the flesh and fat produced within the limits of experimental error, we have a proof that the carbhydrates of the food must have conti'ibuted to* its formation to the extent, at least, of the observed difference. Experiments on Ruminants. — Unfortunately there have been as yet no extensive investigations in which the fat-production of domestic animals, or of any herbivorous animals, under the influence of a definite and suitable ra- tion, has been determined with scientific accuracy, i. e., by careful determination of all the solid, liquid, and gaseous excretions. In considering this question, we can avail ourselves only of the results of so-called " practical " experiments, in which the nutritive effect of the fodder has been de- termined simply by the increase of the live weight of the animal, or perhaps from the dressed weight, or at best from experiments in which the " sensible " (solid and liq- uid) but not the gaseous excretions have been accurately determined. MiLh-fat. — ^In regard to the production of milk-fat by MANtTAI, OF CATTLE-FEEDING. 175 cows we have three investigations, carried out respec- tively hy Voit * in Mimich, E. v. Wolff f in Hohenheim, and G^ Klihn and M. Fleischer:!: in Mockern. In the first a rich fodder vs^as given, in the two others, on the contrary, one less rich in albuminoids. In the following table the sum of the fat of the fodder and the fat which might have been formed from the pro- tein of the latter (51.4 per cent, of the protein consump- tion) is compared with the amount actually found in the milk. The numbers are grammes per day and head : Munich, Experiment a b ' Hohenheim, Mockern, I. n. I. II. Pat 61 fodder. GiTlhs. 318.8 376.0 170.5 166.5 183.5 183.5 Fat from protein. G-nuB. 401.8 308.5 160.1 171.3 79.5 69.5 Total. Grms. 720.6 584.5 330.6 337.8 363.0 353.0 Pat of the milk. Grms. 577.5 337.3 303.3 390.5 277.5 393.0 In the Munich and Hohenheim experiments, the fat available from the two sources named was more than sufficient to account for that .produced in the milk. In Mockern, on the contrary, a small excess of milk-fat was found; but even if this excess had been considerably greater, no definite conclusions in regard to its source could be drawn. Equilibrium between the supply and excretion of nitrogen was, indeed, established in the Mock- • Zeit. f. Biologic, 1869, p. 113. f Emahrung Landw. Hutzthiere, 349. tLandw. V. St.,XU.,451. 176 MANUAL OP CATTLE-FEEDINO. em experiments, as in all the others, but whether the ani- mals were also in equilibrium as to carbon or whether the fat of the body took part in the milk-production, as is so often the case with mUk cows, even when well fed, could only have been decided with certainty by the help of a respiration apparatus. Eaypervments on Fattenmg. — Something more definite as to the source of animal fat may perhaps be learned from the results of fattening experiments on domestic animals, if we at the same time consider that, according to the experiments of Lawes and Gilbert in England (see p. 9), the increase of the live weight in fattening has the following composition in 100 parts : Ash. Protein. Fat. Total Water. 0.06 2.34 1.47 6.44 7.13 7.69 71.5 70.4 66.2 78.0 79.9 75.4 23.0 Sheep 20.1 Oxen 24.6 Average 1.45 7.53 66.6 75.6 24.4 Of late years a large number of fattening experiments have been executed at the various Experiment Stations, especially with sheep. In' these experiments the fodder has been analyzed according to the same methods, the ac- tual increase of weight determined as accurately as possi- ble, and the duration of the experiments made sufficiently long (from two and one-half to fully three months) to nul- lify, to a large extent, the effects of any temporary varia- tions of the live-weight which might occur. If, now, in these experiments, we assume that, according to Lawes & Gilbert's results, 70.4 per cent, of the gain MANUAL OP CATTLE-FEEDING, 177 made consists of fat, we shall have a basis for computing whether the available protein and fat of the food consumed were sufficient to account for the amount of fat actually produced. Obviously, such computations are simply ap- proximate, but at the same time their results have a cer- tain value when derived from a large number of experi- ments. This comparison has been made by the writer in seventy- seven different experiments, viz., fourteen by Henneberg, in Weende, in 1858-63;* six by Stohman, in 1862-63, f and eight in 1864-65, ;): at Brunswick; nine by E. v. Wolff, m 18Y0-71,§ and ten in 1871-72, || at Hohenheim; nine by Henneberg & ^tohmann ; ^ eight by Haubner & Hofmeister, in Dresden; and twelve by F. Krocker, in Proskau. ** Each one hundred parts of protein oxidized in the body was considered to have yielded 51.4 parts of fat, and to this amount was added the ready-formed fat of the fodder. The result, with one or possibly two exceptions, was that in all cases the protein and fat were sufficient to ac- count for the amount of fat formed, although in some of the experiments little margin was left. E. V. Wolff has separated fifty-nine of these experiments into four groups, according to the amount of digestible protein contained in the fodder, with the following results in pounds per day and head : * Jour. f. Landw., 1858, p. 363 ; 1860, p. 1} 1866, p. 303. t Ibid., 1865, 2 Supplement. tibid., 1867, p. 133. § Landw. Jahrb., L, 533. II Ibid., n., 331. 1[ Jour. f. Landw., 1865, Supplement. ** Preuss. Ann. d. Landw., 1869, Sept. and Deo. 178 MANUAL OP CATTLE-FEEDING. DIOXSTSS PBB DAT AHD HXAD. Atksagk. Nutritive ratio. Increase of live-weight per day and bead. Lbs. No. of Ezperimentii. noids. Lbs. Non-nitro- genous nutrients. Lba. 7 0.330 0.368 0.329 0.384 1.648 1.557 1.588 1.538 1 :7.49 1 :5.81 1 :4.70 1 :4.01 0.111 13 0.158 80 0.189 19 0.206 These mimbers speak very decidedly for tlie favorable action of the albtunirioids on the fat production ; a greater increase of weight of the animal accompanies a greater supply of albuminoids, while the quantity of the non-nitro- genous nutrients is nearly the same in all the groups, and therefore can have exerted no essential influence on the increase of weight. If we take into account, however, the fact that, in all probability, some of the so-called protein in these experi- ments was really not protein, but amides or similar bodies, which, though they may aid the flesh production, can hardly serve as a source of fat, the number of cases which indicate a formation of fat from carbhydrates wUl probably be considerably increased. Still more decided results pointing toward a direct par- ticipation of the carbhydrates in the production of fat were obtained in the experiments of Henneberg, Kern, and "Wattenberg,* already referred to for another purpose in Chapter I. In this investigation two sheep were killed at the begin- ' Jour. f. Landw., Jahrg. 26, p. 549. MANUAJi OF OATTLE-FEEDING. 179 ning of the experiment, and the amount of the various components of their bodies (flesh, fat, bones, tendons, etc.) determined as accurately as possible, while two similar sheep were examined in the same way after having been fattened for several months. The experimenters themselves did not consider the ques- tion of the origin of the fat, but E. v. WolfE * has shown from their results that a portion of it must have been formed from carbhydrates. The carcases of the unfattened and fattened animals had the following composition : Dry and fat- tree flesh. Grms. Dry fat. Qrms, Fresh bonea. Grms. Fresh tendons. Grms. Unfattened 3,465 2,485 5,406 15,077 2,530 2,566 2,488 Fattened 1,818 Difference , , +20 +9,671 +36 -670 The result of the fattening was almost wholly a gain of fat. The gain of 9,671 grms. of fat does not include the fat of the wool nor the small quantities contained in skin, head, legs, etc., etc., which would probably have amounted to 200 grms. more. This, however, we wiU leave out of the account. During the time of the experiment the animals digested about 9,490 grms. of protein and 2,554 grms. of crude fat (ether extract). Assuming that the digested ether extract produced an equal amount of fat, which is hardly proba- *Landw. Jahrb., YIII., I. Supplement, p. 180 MANUAL OF CATTLE-FEEDING. ble, and also that the digested protein yielded 51.4 per cent, of its weight of fat, we obtain the following num- bers: GrmB. Fat actually gained 9,671 Fat from ether extract 3,554 gnus. " '" protein (9,490 X 0.514) 4,878 " Total 7,433 Fat unaccounted for 2,239 It thus appears that at least 2,239 grms. of fat must have been produced from carbhydrates. In reality the amount was considerably greater, however. Not only have we not taken iato account the fat of the offal, but the amount of protein available for the formation of fat is less than appears above. In the first place, a considerable growth of wool took place, demanding, of course, a supply of protein, and in the second place, one of the feeding- stuffs used (lucerne hay) has been shown by KeUner * to contain a considerable proportion of amides, which were here reckoned as albmninoids. These results indicate, most decidedly, that in these ex- periments a considerable amount of fat was formed from some other materials of the food than fat or protein. Experiments on S'wine. — ^Nearly or quite aU the ex- periments which have been made on swine have yielded results favorable to the belief ia the formation of fat from carbhydrates. The earliest investigations were those of Lawes & Gil- bert, in 1850, which, on the assumption that the increase in the live weight had the composition determined by them * Landw. Jahrb., YIII., I. Supplement, p. 243. MANUAL OF CATTLE-FEEDING. 181 in other experiments (see pp. 9 and 176), showed, in many cases, a greater gain of fat than could be accounted for by the protein and fat of the food. Later experiments have given similar and even more decided results. An iacrease of 100 pounds in the live- weight has frequently been obtained with a fodder contain- ing 10 to 15 lbs. of fat and 60 to 70 lbs. of proteui. In one case the above gain was made on a fodder containing only 40.8 lbs. of protein and 6.8 lbs. of fat, while the weight of the animals increased from 70.5 lbs. at the beginning of the experiment to 246.5 lbs. at its close. These results appear almost iacomprehensible unless we admit a pro- duction of fat from carbhydrates. Weiske & Wildt,* in Proskau, have attempted to solve the problem by experiments on the same plan as those of Henneberg, Kern & Wattenberg on sheep. Of four six- weeks-old pigs, two were killed at the beginning of the experiment, and the total quantity of flesh and fat in their bodies was determined. Of the other two, one received a fodder rather poor in protein for 184 days. The second, which was to have been fed with a fodder rich in protein, became sick, and was therefore excluded from the experi- ment. At the close of the feeding, the sound animal was killed and the flesh and fat present in his body determined, as in the two other animals at the beginning of the experiment. On the assumption, now, that the first two pigs had, at the time they were killed, the same composition as the one which was fattened, we have only to subtract the average of the former from the latter to find the amount of flesh and fat produced during the feeding. * Zeitschrift fiir Biologie, X., 1. 182 MANUAL OF OATTLE-FEEDING. Protein. Kilos. Fat. Kilos. 3.3835 1.0410 7.0138 TJnfatteued , i 0.8740 1.3435 14.3344 6.1398 Digested from food 0.5748 Fat f oimed in body 13.0819 6.5650 Protein available for fat formation Available protein x 0.514 = 6.7241 According to these figures, the protein and fat of the food were sufficient to cover the amount of fat produced. Various circumstances, however, unite to lessen the value of the result reached. From some cause, the growth of the animal was unusually slow. Furthermore, the fod- der used consisted of potatoes, rye bran, and starch, and at the time when this research was made the presence of amides in potatoes had not been discovered. Since then from 26.8 to 39.9 per cent, of the total nitrogen of pota- toes has been found in various experiments to exist in the form of amides, and if we take this fact iato account, the above calculation yields very different results. Out of the total digested protein, 11.1227 kilos, came from the potatoes. Assuming 26.8 per cent, of this to be amides, there remain 8.1419 kilos., making, with 3.2017 kilos, from the bran, a total of 11.3436 kilos, of true pro- tein digested.* The figures then stand as follows : * On the assumption that protein and amides were digested to the same extent. It is more than probable that the amides were wholly digestible, which would g^iye a still greater deduction. MANUAL OF OATTLE-FEEBING. 183 Protein. Kilos. Fat. Kilos. Produced 1.2425 11.3486 6 1398 From food 5748 Fat formed in body. 10.1011 5.5650 Protein available for fat production ... Available protein x 0.514 — 6.1920 The result is exactly the opposite of that previously ob- tained. The difference is too small to prove a formation of fat from carbhydrates, more especially as a participation of the amides in fat-building is not altogether impossible, but it deprives the experiment of all value as a proof that- cai'bhydrates do not furnish material for fat. Some late feeding experiments on swine by E. v. Wolff,* at Hohenheim, have also given results which seem to show quite plainly a formation of fat from carbhydrates. A gain of 100 pounds was made from an amount of fodder contain- ing from 47.1 to 71.4 lbs. of digestible protein, and from 1.6 to 3,5 lbs. of digestible fat. The larger of these quan- tities could yield, at most, 40.2 lbs. of fat, while, according to Lawes & Gilbert, 100 lbs. increase would contain at least 70 lbs. of fat. Experiments on Dogs. — In regard to the dog, we can assert that in no case is the assumption of a formation of fat from carbhydrates necessary. AS has already been mentioned, large quantities of fat may be deposited ia the body from the fat or the albuminoids of the food; but in twenty-two respiration experiments made by Petten- * Landv, Jarhrbiicher, VIII., I. Supplement, 238. 184 MANUAL OF CATTLE-FEEDING. kofer & Voit, the fat deposited in the body was always fully accounted for by that which could be formed from the amount of albuminoids decomposed ia the body, and was proportional not to the carbhydrates but to the albu- minoids of the food. With the same quantity of albumi- noids in the food, an increase of the carbhydrates caused no increase iu the amoimt of fat formed, but only an in- creased excretion of carbonic acid, showing that the carb- hydrates were rapidly oxidized in the blood.* On the other hand, an increase ia the albuminoids of the food — the quantity of carbhydrates remaining the same — caused a very considerable increase in the amount of fat pro- duced, thus showing an intimate connection between the supply of protein in the food and the formation of fat in the body. Sovirces of Uncertainty. — Having considered the ex- perimental evidence bearing on the question of the sources of animal fat, it now becomes necessary to consider briefly how much weight attaches to this evidence. It must be admitted at once that the data now at our command are not sufficient to enable us to solve the prob- lem. No thorough and accurate scientific study of the subject has yet been made, if we except Pettenkofer & Voit's experiments on dogs. The conclusions drawn in the preceding paragraphs from experiments on farm ani- *It shonld be said that, according to Zaatz {Landw. JahrbucTier, VIII., 94), carbhydrates cause no increase in the excretion of carbonic acid w?ien introduced directly into tJie blood, but only when taken into the alimentaiy canal. According to him, the increased excretion of carbonic acid is caused by the excitation of the nerves of the stomach and intestines. In a practical point of view, however, the result is mnch the same, since the carbhydrates of the food must be taken into the alimentary canal, and it makes little difference whether the car- bonic acid is produced from them or from the tissues of the body. MANUAL OF CATTLE-FEEDING, 186 mals are to be regarded only as very probable, not as cer- tain. In the first place, we do not know how much fat was actually formed in these experiments. The estimates of its amount, based on the composition of the increase of fattening animals as determined by Lawes & Gilbert, are obviously very uncertain ; and even in such experiments as those of Henneberg, Kern & Wat- tenberg, and of Weiske & Wildt, it is highly improbable that the animals killed and analyzed at the beginning of the experiments had exactly the composition of those re- served to be fattened, and we have no means of judging of the amount of the dLfiference. Again, in all cases we have assumed that 100 parts of protein decomposed in the body gave rise to 51.4 parts of fat. ]^ow this number is a purely theoretical one, based on a calculation by Henneberg of the greatest amount of fat which could possibly be formed from a given weight of protein; and, whUe there can be no doubt that fat is formed from protein, it is very doubtful whether this maximum amount is formed in every, or even in any, case. It is a commonly observed fact that when a chemical com- pound breaks up into simpler bodies, some of its latent energy is set free, either as heat or in some other form. Zuntz {loo. cit; p. 96) has, however, shown that such a formation of fat and urea from protein as we have been supposing, is only possible on the condition that the result- ing products contain all the latent energy of the decom- posed protein, and that none is given off in the decompo- sition. This, Zuntz remarks, is a process wholly without analogy in the animal body, where all decompositions are accompanied by the setting free of considerable quantities 186 MANUAL OP CATTLE-FEEDING. of heat. Without laying too much stress upon this point, we must still admit its iuiportance. If Zuntz's ground be well taken, then it would appear that in all the calculations on this subject we must reduce the amount of fat obtainable from the protein of the food, leaving stUl more to be formed from other nutrients. Conclusions. — The following conclusions regarding the sources of animal fat appear to be justified by our present knowledge on the subject : 1st. Animal fat may be formed from the fat of the food. 2d. It may be formed from the protein of the food. 3d. Assuming the accuracy of the factor 0.514 for the conversion of protein into fat, the amount of fat produced by the dog is covered by the protein and fat of the food. 4th. Kuminants have in some cases produced less, and in some cases more, fat than could be accounted for by the protein and fat of the fodder. 5th. Swine have, in the majority of cases, produced more fat than could have been formed from the protein and fat of the food. When we consider the fact that the proofs of the for- mation of fat exclusively from protein are essentially negative in their nature, while those of its formation from carbhydrates are direct, it would seem that we must admit that the carbhydrates may serve as a source of fat to swine, and also, under some circumstances at least, to herbivora. This, however, is equivalent to admitting it for aU animals, since there are no essential differences known in the nutri- tive processes of the higher animals. With our present imperfect knowledge, we must regard both protein and carbhydrates as sources of fat, while the final settlement of the question, as weU as the determina- mAJNUALi UJB' «JATTLiJS-J!EJ£L»lJN«. 1C5/ tion of the part played by each, must be left to the deci- sion of more exact experiments. .Having thus considered at some length the important question of the sources of animal fat, we are prepared to take up the general laws which regulate its formation. It is evident, however, that untU we know with certainty the source from whence the fat of the body is derived, our at- tempts to formulate the laws of its production must be more or less tentative. Most of our knowledge upon this subject is due to the labors of Pettenkofer & Voit at Mu- nich. These investigators hold that fat is not formed from carbhydrates in the body, and their experiments, which were made before many of the facts spoken of in the preceding paragraphs were known, are interpreted in accordance with that belief. If we add to this fact the great labor involved in investigations of this kind, the use of the complicated respiration apparatus being essential, we can readily understand why our knowledge of the laws of the formation of fat should be in some respects unsatis- factory. At the same time, what is already known is very valuable and offers important aid to the formation of a rational theory of feeding. § 2. Feeding with Fat Alone. The Fat of the Food protects the Body-fat. — In Pettenkofer & Yoit's experiments* a dog was in one case allowed to fast for eight days, and in a second experi- ment was fed daily svith 100 grammes of pure fat, about the amount which was found to have been oxidized daily in the first experiment. On the eighth day the following results were obtained : * ZeitBchrift f. Biologie, V., 369. 188 MANUAL OF CATTL-E-PEEDING. Gmu. Fat eaten per day Consnmption of flesh in body. " " fat* " Gain ( + ) or loss (— ) of fat 138 114 -99 WMle, as we liave already learned, fat does not hinder the protein-consiunption in the body but rather tends to increase it, when fed alone, the loss of fat is entirely stopped by a quantity equal to that lost in hunger. That is, an increased supply of fat does not, like an increase of albuminoids, augment the consumption, but takes the place of that before consumed, pound for pound. The simplest way of explaining this is by the assump- tion that the fat of the food is more easily oxidized than that already deposited in the body, and that the former therefore possesses itself of the oxygen of the blood and protects the latter from oxidation. A Geiin of Fat may accompany a Loss of Flesh. — In another experiment, in which a large quantity (350 grammes daUy) of fat was fed, the loss of flesh on the . second day amounted to 227 grammes, and at the same time 186 grammes of fat were retained in the body. The same fact is shown by the second experiment on p. 172. § 3. FEBDma with Peotetn Alone. Protein can protect the Fat of the Body from Oxi- dation. — The following experiments by Pettenkofer & Voitjf on a dog fed exclusively with meat, were made with the help of the respiration apparatus : * Inclnding that formed from protein, t Zeitschrift f. Biologic, VIL, 489. MANUAL OF CATTLE-FEEDING. 189 Heat ted. Ormif. Flesh coniumed In body. Grms. Gain( + ) or losB (— ) of flesh. GimB. Gaiii(.|.) or loss (— ) of fat. Grms. 165 -165 -95 500 599 -99 -47 1,000 1079 -79 -19 1,500 1,500 +4 1,800 1,757 +43 +1 3,000 2,044 -44 +58 2,500 2,513 -13 + 57 While witSi a small ration of meat the animal lost both flesh and fat, a medium ration (1,500 grammes) sufficed to stop the loss, not only of flesh but also of fat, and larger amounts, while they could not, for the reasons explained in the preceding chapter, cause any considerable gain of flesh, did cause a gain of fat ; *. e., not only did the albu- minoids protect the body-fat from oxidation, but new fat was formed from them and laid up in the body. These results are most simply explained by the assiunp- tion that the fat formed in the body from albuminoids, like that contained as such in the food, is more readily oxidized than that already stored up in the body. Incidentally these experiments give proof of the possi- bility of the formation of fat from protein, and also of the statement just made that a gain of fat may accompany a loss of flesh. § 4. Feeding with Protein and Fat. Protein protects the Pat of the Food from. Oxi- dation. — Since in the fodder of herbivorous animals fat is usually present in small quantity, and is of comparatively 190 MANUAL OF CATTLE-FEEDING. little importance, it will be sufficient to indicate in outline the general results of experiments on carnivorous animals. It has already been shown, that fat is produced in the body in the decomposition of albuminoids, and that with a comparatively large amount of the latter the fat thus formed may equal the amount oxidized in the body. If, now, to such a ration we add a certain quantity of fat, say 100 grammes, we have just so much more fat available for deposition in the body, since the consimiption of fat does not increase with the supply as does that of the albuminoids. Thus, in a series of experiments made by Pettenkofer & Voit,* a dog was fed daily 1,500 grammes of meat, a quantity which had been found sufficient to keep him in equilibrium both as regards flesh and fat, and received also varying quantities of fat. Food. Effect oh Bodx. Meat. GrmB. Fat. Grms. Consnmptaon of flesh. Grms. Gain of flesh. GnuB. Consumption of fat.t GrmB. Gain of fat. Grms. 1,500 1,500 J,500 1,500 1,500 30 60 100 100 150 1,457 1,501 1,402 1,451 1,455 +43 - 1 +98 +49 +45 158 186 163 151 174 33 89 91 109 136 The addition of fat caused a deposition of it in the body, and the amount thus laid up waSj in 'nearly every case, pro- portional to that fed. » Zeitsohrift f. Biologie, JX., 30. f Including the fat prodncedfrom protein. MANUAL OF OATTLE-FEEDIN& 191 That is, the amount of fat yielded by the decomposition of the albuminoids was sufficient to supply what was needed for the vital processes, and the extra amoimt added was stored up in the body. This is generally expressed by saying that the fat produced from the albuminoids is more easily oxidized than that of the food, or, in other words, that the protein protects the fat from oxidation, but there seems to be no absolute proof that such is the case. There is simply an excess of fat present over that required, and this excess is laid up against future needs. The fat pro- duced from the albuminoids is always to be added to that given in the food in estimating the effect of a fodder. If much protein is fed, the protein consumption in the body will be great, and while little or no organized protein is produced, large quantities of fat may be laid on. A too great accumulation of circulatory protein, however, is to be avoided, since it increases the rapidity of the circulation of fluids in the tissues, and tends to produce a more rapid oxidation. § 5. Feeding with Protein and Carbhtdbatbs. The only really scientific experiments on this poiat are by Pettenkofer & Voit,* who, as we have seen, do not be- lieve in the possibility of a formation of fat from carbhy- drates. The experiments and results now to be given form a powerful argument in favor of the correctness of their view in its application to the animal experimented on. At the same time we must not forget that other experi- ments strongly indicate that, in some cases, fat is formed directly from carbhydrates. ♦ ^eitsohrift f. Biologie, IX, 435. 192 MANUAL OF CATTLE-FEEDING. Carbhydrates may be Oxidized instead of Fat. — By the addition of carbhydrates to albuminoid food the protein consumption is, indeed, somewhat decreased, but never stopped ; but the carbhydrates, when present in suf- ficient quantity, may protect entirely from oxidation the fat of the body, and also the fat of the food and that formed from protein. This effect of the carbhydrates becomes evident when we compare some of the experiments in which the animal was fed on meat alone with those in which the same quantity of meat was fed with the addition of starch or sugar. Food. NUTBITITE BfFBCT. Heat. Gram. starch or sugar. Grms. Fat. GrmB. Consnmption of flesh. Grms. Lo88 of Consumption flesh. of fat.* Grms. . Grms, Gain of fat. Grms. 500 500 500 167 182 6 599 530 537 99 30 37 108 50 43 -47 + 14 + 16 The carbhydrates of the food in the second and third experiments caused the fat consumption to decrease to less than half its former amount and made a corresponding gain of fat possible. This they apparently accomplished by possessing themselves of the oxygen which otherwise would have combined with the fat ; in other words, they were oxidized in place of the latter. Difierence in the Action of Carbhydrates and Fat. — ^Pettenkofer & Voit have foxmd that while an increase * Including that formed from protein. MANUAL OF CATTLE-FEEDING. 193 of fat in the food causes an increased deposition of fat in the body, an increase of the carbhydrates does this only up to a certain limit. For example, if fat be fed to a fast- ing animal in more than sufficient quantity to supply the necessary consumption, the excess is deposited in the body, and the more fat is fed the more is thus deposited. If carbhydrates be fed in this way, they are oxidized in the blood, and a corresponding quantity of the body-fat and of that produced from the decomposition of the albuminoids of the body is protected from destruction. If enough carbhydrates are fed, all the fat separated from the pro- tein may be deposited as body-fat. Thus far the action is essentially like that of fat, but if we increase the carbhy- drates heyond thispoimt wc get 7w' further layi/ng on of fat. The quantity of fat deposited in the body under such cir- cumstances is found • to be proportional to the amount of the protein consumption, and the excess of carbhydrates is simply burned up, producing an increased excretion of car- bonic acid.* Essentially the same results were obtained when carbhydrates were fed along with albuminoids. In no case was the gain of fat greater than corresponded to the ready-formed fat of the food and that which could be produced from the albuminoids, and any excess of carbhy- drates over that required to protect this amount of fat from oxidation produced no effect except an increased excretion of carbonic acid. On the other hand, it has been observed that when a large quantity of carbhydrates are fed, and the albumi- noids are gradually increased, the gain of fat also in- creases. The following experiments illustrate this : * See foot-note, p. 184. 194 MANUAL OF OATTLE-FEEDING. Curbhydrates (starch) of food. Grma. Meat of food. G-rms. Flesh consnmptiun. Grms. Oain of fat. GrmB, 379 379 379 800 1,800 211 608 1,469 41 69 122 The increased oxidation of albuminoids in the body furnished more material for the formation of fat, and the carbhydrates were suflScient to protect a large part of it from oxidation. These and similar researches obviously speak strongly in favor of the theory that fat is formed from the albuminoids and not from the carbhydrates. Naturally, a certain relation must subsist between the latter and the amount of fat formed. Since the carbhy- drates protect the fat from oxidation, a greater quantity of them must protect more fat up to a certain limit ; but if more carbhydrates are given than are necessary to protect the fat, the excess seems not to produce fat but to be oxidized. The relative Effect of Fat and Carbhydrates in effecting a gain of fat or protecting the body fat from oxidation, is not in proportion to their respiration equiva- lents. By the respiration equivalent, as explained on p. 157, we imderstand the relative quantities of heat which equal weights of the given substances will produce when com- pletely burned. It may be expressed in another way by saying that they represent the relative amounts of oxygen with which equal weights of the given substances combine when completely oxidized. Thus, if a certain weight of starch, e. g., re- MANUAL OF CATTLE-FEEDING. 195 quires for its complete combustion one gramme of oxygen, the same weight of fat will require 2.5 grammes of oxygen ; and if we represent the respiration equivalent of starch by 1, that of fat is 2.6, while that of the other carbhydrates is practically equal to that of starch, viz., 1. Since, now, the chief office of the carbhydrates seems to be to protect other substances from oxidation by them- selves combining with the oxygen, we might naturally ex- pect that one part of fat would be equivalent in this respect to 2.5 parts of a carbhydrate ; and before any exact obser- vations had been made, this was assumed to be the case. The few experiments as yet made, however, have shown that this assumption is erroneous, and that one part of fat is equivalent not to 2.5 parts of a carbhydrate, but to only about 1.75 parts, while, as we have seen (p. 157), their action in decreasing the protein consumption is about the same, weight for weight. In the animal body we have to do, not with a machine into which fuel is put to be burned, but with a living organism. The materials of the body and the food are decomposed in the performance of the vital processes, while the burning of them by the oxygen of the blood is only a secondary process, and any conclu- sions drawn from the chemical composition of nutrients and their behavior outside the body, are of very uncertain application to the complicated processes which take place within it. The importance of these facts for the practice of feed- ing is obvious. The carbhydrates are the cheapest of the nutrients, and the most easily digestible, while fat is ex- pensive and difficult of digestion by herbivorous animals. When we add to the two facts just mentioned — viz., the equivalence of fat and carbhydrates in their effect on flesh production, and the value of the latter as an aid to fat pro- 196 MAinjAL OP CATTLE-FEEDING. duction — the possibility of a direct formation of fat from carbhydrates, the great importance of this class of nutrients becomes evident. Fattening. — In fattening animals for market, the chief endeavor is to produce fat, and only in a subordinate de- gree to cause a formation of flesh. Indeed, after an animal has completed its growth but little more formation of actual flesh (organized protein) takes place, although the quantity of circulatory protein, and so the juiciness of the meat, may be increased. In all cases, a certain minimum amount of protein and non-nitrogenous nutrients is necessary to maintain an ani- mal m statu quo / but this amoimt varies according to the condition of the body. If the latter is rich in circulatory protein on account of previous rich feeding, the food must contain much protein ; if it contains little circulatory pro- tein, a small amount of albuminoids in the fodder will suffice. If the body is fat, a smaller ration of albuminoids is necessary to maintain its condition than when it is lean. If we increase the fodder beyond the amount necessary for maintenance, a production of some sort results. If the amount of the non-nitrogenous nutrients be in- creased, we shall get (up to a certain limit at least) a pro- duction of fat ; i£ the protein be increased, we shall have an increased protein consiunption in the body, but also a gain both of flesh and fat. The proper proportions of nitrogenous and non-nitro- genous nutrients in a fodder, then, obviously depend on the object of the feeding. If we desire to render the body rich in protein, to cause a good development of its organs, and render it capable of great exertions, we shall feed plenty of albuminoids together with enough non-nitro- genous nutrients to protect the fat of the body from oxi- MAITUAL OF OATTLE-FEEDINa. 197 dation and to diminish the protein consumption as much as possible while not causing any considerable fattening, and we shall give the animal as much of this fodder as possible, because the greater the amount of food of a given composition eaten, the greater, other things being equal, is both the absolute and the relative production. (See p. 167.) On the other hand, if we wish to fatten the animal, we shall proceed differently. With any given number of pounds of protein in the daily fodder, the greater the amount of non-nitrogenous nutrients taken into the sys- tem the more fat is protected from oxidation and the less becomes the protein consumption. In other words, having once fixed on the number of pounds of protein to be given per day and head, the more carbhydrates and fat we can introduce into the system along with it the greater wUl be the production both of flesh and fat. We shall consequently incline to make the nutritive ratio of our fattening fodder wider than that for working animals ; but in doing this we shall not forget that a cer- tain absolute amount of protein is necessary. Leaving out of account the possible formation of fat from carbhydrates, there is no doubt that a certain propor- tion of protein in the fodder is essential to rapid and profitable fattening, especially of ruminants, while it is, of course, the only source of material for the formation of flesh. Since, now, an animal can consume only a certain total amount of food, our first care will be to see that that food contains enough protein ; while, in the second place, we shall introduce into it enough carbhydrates and fat to insure a production of fat and prevent any unnecessary protein consumption. Thus it will be seen that a consideration of the general principles brought out in the last two chapters leads to im* 198 MAKUAL OP CATTLE-FEEDING. portant practical conclusions. The application of these general principles to the feeding of domestic animals, the determination of the quantity and proportions of the various nutrients which are necessary to attain most speedily and profitably the various ends of feeding, forms the object of the science of cattle-feeding, and it is the clear recogni- tion of this fact and the intelligent pursuit of this object which has caused the rapid advances of the past few years. What has already been achieved in this respect will form the subject-matter of Part III. g 6. XtrPLUENCB OP Othbb Conditions on the Pbodtjotion op Fat. Influence of the Fat of the Body. — ^In a body rich in fat the total fat-consumption, and also the proportion of the fat of the food which is oxidized, is greater than when the body contains little fat ; in the latter case, the fat from the food, or from the oxidation of the albuminoids, is more readily stored up, while in the former case greater obsta- cles seem to stand in the way of a further accumulation of fat. Excessive Drinking — According to our present knowl- edge, excessive drinking of water increases the consump- tion of fat in the body, just as it does that of the protein. (See p. 135.) Too watery fodder and too much drinking are therefore to be avoided, especially in fattening, if we wish to attain the most rapid and abundant formation of flesh and fat. Too lo-w or too high a Temperature of the stall seems also to act unfavorably on fattening : the first, be- cause an increased oxidation of food constituents is neces- sary to maintain the vital heat ; the second, because it causes perspiration, which exerts two evil effects : first, by MANUAL OF CATTLE-FEEDING. 199 causing increased drinking, and second, by absorbing heat from the body by its evaporation, just as water sprinkled on the floor on a hot day absorbs heat as it evaporates, and so cools the room. Every such loss of heat is equivalent to a loss of substance, since the heat is produced by the oxidation of the materials of the body or of the food. Too high a temperature is also liable to make the animals rest- less and diminish their appetite. A medium temperature of from 55° to 70° F. is the most favorable for fattening. Muscular Exertion, as we shall see more in detail in the next chapter, increases the consumption of fat very considerably. Too much movement by fattening or milk- ing animals is therefore to be avoided. This is true not only of outward motions but of the internal motions of the body in digestion, etc. If a very bulky fodder be given, the increased work of moving it in and through the diges- tive apparatus cannot but have its influence in increasing the oxidation and destruction of fat. Doubtless one of the advantages of concentrated and easily-digestible fodders is' the saving in internal work which they effect. The Amount of Oxygen taken up by the Blood is a not unimportant factor in the production of fat. The decompositions which take place in the body are, as we have already seen, vital processes, and .the taking up of oxygen is a consequence and not a cause of them. At the same time, the maximum amount of oxygen that can be introduced into the system is determined by the amount of blood and its content of haemoglobin, this sub- stance being the active agent in taking up the gas, and this, of course, sets a limit to the amount of matter that can be oxidized in the system. Consequently a small amount of blood and a small proportion of haemoglobin are condi- tions favorable for the production of fat. 200 MANUAL OP CATTLE-FEEDING. According to tlie obseryations of Subbotin,* the chief factor in determining the amount of haemoglobin in the blood seems to be the nature of the food. The blood of a dog, e. g., fed on a richly nitrogenous diet, was found to have 13.73 per cent, of haemoglobin, while on a non-nitro- genous diet it sank to 9.52 per cent. He also found that the blood of herbivorous animals, which generally receive a fodder comparatively poor in nitrogen, contained less haemoglobin than that of carnivorous animals, which receive a more nitrogenous food. We shall see in Chapter Vlil. that an increase of the albuminoids of the food increases the capacity of the body to store up oxygen, and here we get a hint as to the way in which this effect may be produced. One other factor determining the amount of haemoglo- bin seems to be the amount of fat already contained in the body. Subbotin found considerably less in the blood of lean than of fat animals. That a decrease of the haemoglobin aids the production of fat is indicated by various facts. In some parts of Germany bleeding is resorted to, to in- crease the rapidity of fattening, and it has been found by respiration experiments that this operation, while it in- creases the protein consumption, decreases that of fat, apparently by removing part of the blood corpuscles (haemoglobin), the agents by which oxygen is introduced into the system. It is also a fact of experience that the body, when deficient in blood, is often inclined to lay on fat. It is well known, too, that herbivorous animals are, in general, easier to fatten than carnivorous, and it is more than probable that this is due, in part at least, to the * Zeitsohr. t. Biologie, VU., 185. MANUAL OF CATTtE-FEEDIN0. 301 smaller amount of lisemoglobin contained in their blood, while the diiferences observed between different breeds in this respect may be partly owing to the same cause. In cases of phosphorus-poisoning, an enormous formation of fat is observed, amounting sometimes to fatty degener- ation of the tissues. Pliosphorus acts as a poison by depriving the blood of oxygen, and as one of the effects of this we see an abnormal formation of fat, due apparently to the poverty of the blood as regards oxygen. The amount of oxygen taken up by the blood must also be influenced by the amount of lung surface, the rapidity of circulation and respiration, etc. ; but while it is a popular and perhaps well-founded belief that the differences ob- served between different animals as regards ease of fatten- ing, are largely due to differences in build, especially in the size of the hmgs, there has been as yet no scientific study of this iateresting question. 9* CHAPTER Yin. THE PEODUCTION OF WOEK. In its most general sense, tlie production of work means the conversion of latent into actual energy. In the ani- mal, it is the latent energy contained in the various com- ponents of the food or the body, which is thus converted, during the resolution of these components into simpler substances. Every ingredient of the food contains a cer- tain fixed amount of force ; every one of the simpler com- pounds into which it may split up in the body also con- tains its smaller but equally definite amount of force, and the difference between the latter and the amount contained in the original substance expresses exactly the amount of force which that substance is capable of contributing to the body. The production of force in the body has been compared to the operations of a steam-engine. In the engine, the force exerted is set free as heat from the coal burned under the boiler, and is then converted, by appropriate mechanical arrangements, into motion of the engine ; in the body the force set free by the combustion of the materials of the food appears partly as heat and partly in other forms. Just as the burning of fuel under a steam-boUer may do various kinds of work, such as heating, producing chemical change, or causing motion of the en- gine, which motion, again, may be applied to various pur- poses, such as pumping water for the boiler, drawing coal MANUAL OF CATTLE-FEEDING. 203 for the fire, driving the .machinery of a shop, etc., so the energy set free in the body takes various forms. It may appear as heat, or as motion, it may take the form of elec- trical currents, or it may produce chemical changes, such as the formation of a complex compound out of simple ones. All these phenomena we class together under the general name of the production of work. It is obvious at once that the production of work is an- tagonistic to the formation of the material products for which animals are frequently kept. All work is performed at the expense of food or tissue, and the more work is per- formed the less material remains for the production of flesh, fat, milk, etc. This is a common observation as regards external work — ^no one would undertake to fatten a laboring animal — but it is equally true of such less obvious forms of work as the production of heat or of chemical change. Plainly, then, we have a very practical interest in knowing what constituents of the food or of the body are destroyed in the performance of the various kinds of work, since all the material losses thus occasioned must finally be supplied by the food. One kind of work, viz., muscular exertion, has been the subject of much study and controversy ; and though we do not even yet know with certainty what substance or sub- stances are the source of muscular power, yet what has been learned is of great value. Other forms of work, on the contrary, have received comparatively little attention, and offer a wide field for investigation. In the following pages we shall take up first the pro- duction of external work and its bearings on the feeding of working animals, and then attend to a few considerations concerning the internal work of the body. 204 MANUAL OP CATTLE-FEEDING. g 1. Effects of MtrscuiiAE Exebtiow oh Excbbtion. Voit's Experiments. — ^It was formerly the common belief that continued activity of the muscles caused a wear- ing out of those organs, and, as a consequence, largely in- creased the protein consumption and the excretion of nitrogen. This belief, however, was never founded on experimental evidence, and has now been rendered un- tenable in its original form. Karl Toit, of Munich, was the first to make exact ex- periments on the subject, and in 1860 he published the results of his researches,* which showed that, contrary to the then generally accepted theory, muscular exertion did not increase the amount of protein decomposed in the body. TTiR experiments were made on a dog weighing about 32 kilogrammes (70 lbs.). The work which he performed on the working-days (by running in a treadmill) was very considerable, being estimated at 1.7 kilogramme-metres f per second for the whole twenty-four hours (the work being actually performed in six periods of ten minutes each), while the work performed by a man working eight hours in the twenty-four is estimated at only 2.3 kilo- gramme-metres per second for the twenty -four hours. In some of the experiments the animal received no food ; in others he was given a daily ration of 1,500 grammes of fat-free meat, with which amount the body was allowed to come into equilibrium before the beginning of the experi- ment. The diet on the resting and working-days was al- ways the same, except that the aninial was allowed to drink all the water he desired. Each experiment extended * " Unteisnchaiigen tiber den Einflnss dea Kochsalzes, des KaSee's und der Muskelbewegtmgen auf den StofEweohsel," 18S0. f A kilogramme-metre is the amount of force required to raise one kilogramme through a space of one metre, in opposition to gravity. MANUAL OF CATTLE-FEEDING. 205 over three days. The following results are averages for twenty-four hours : Number of Experiment. Meat eaten. GtrmB. Water drunk, G-rmB. trrine excreted. Grms. 258 186 872 518 123 145 527 186 125 143 182 1,060 657 1,330 140 1,081 412 1,164 63 1,040 TJrea excreted. Grm&. II. in. IV. Best. 14.3 16.6 11.9 12.3 10.9 109.8 117.2 109.9 114.1 110.6 The 1,500 grammes of meat eaten in Experiments HI. and rV". contained 1,138 grammes of water, which is to be added to the amount drunk. These results show, at most, only a very slight increase of the protein consumption on the working days. On the days of fasting the increase, as nieasured by the excretion of urea, was 11.6 per cent., and with the meat ration only 4.8 per cent. ; and even this small increase appears to be due, not to the work but to the greater amount of water drunk and excreted in the urine, since, as we have already learned (p. 135), an increased excretion of water in the urine causes an increase in the protein consuniption. Voit found that an increase of 100 grammes of water in the urine caused, in the dog, a plus of 1.7 grammes of urea. If this relation is applicable to the above experiments, it 206 MANUAL OF OATTLE-PEEDING. practically covers tlie comparatively slight increase of urea observed on the working days, and we must consequently assume that muscular exertion does not essentially increase the protein consumption in the body. Experiments by Pettenkofer & Volt. — The correct- ness of this conclusion is shown by some subsequent ex- periments by Pettenkofer & Voit * on a man, in which the amount of water drunk was regulated, and the above- mentioned sovu-ce of uncertainty thus avoided. In these experiments the respiratory products were also determined, and the influence of work upon the non-nitrogenous con- stituents of the body thus ascertained. On the work-days the subject of the experiments turned for nine hours, with occasional pauses, a heavy wheel pro- vided with a brake, and at night felt fatigiied as after a hard day's work or a long march. With the aid of the respiration apparatus the following numbers, which all refer to a space of twenty-four hours and are mostly the average of two or three concordant experiments, were obtained : Nitrogen of urine. Grms. Carbonic acid ex- creted. Grms. Wateb Exceeted. Oxygen taken np. Grms. Number In urine. Grma. Evaporated. Grms. of experi- ments. FABTIHa. Best Work........ AvzBAOE Diet. Rest Work 12.4 12.3 17.0 17.3 716 1,187 928 1,209 1,006 746 1,218 1,155 821 1,777 931 1,727 762 1,072 832 981 2 1 3 2 These figures prove most decidefdly that the protein con- sumption is no greater during work than during rest, but • ZeitBohrift f. Biologie, n., 478-500. MANUAL OP CATTLE-FEEDING. 207 that, on the other hand, the consumption of fat, and as a result the excretion of carbonic acid and taking up of oxy- gen, is greatly increased, as is also the amount of water evaporated through lungs and skin. In hunger the differ- ence between the carbonic acid in rest and in work is more considerable (471 grammes) than on an average diet (281 grammes) ; the oxygen shows a similar result, 310 grammes against 148 grammes, while the differences in the water evaporated are relatively less, viz., 956 and 796 grammes. One might perhaps be inclined to believe that while the total amount of albuminoids consumed in the twenty-four hours was the same, the amount was larger during the period of work, and correspondingly less during the hours of rest. In order to test this, the experiments were each divided into two parts, the time from 6 a.m. to 6 p.m., in the course of which the work was performed, being desig- nated as day, and the time from 6 p.m. to 6 a.m. as night. The foUovdng results were obtained for the nitrogen, car- bonic acid, and water excreted : Fabtiho. Atsbaoe Diet. Best. Work. Best. Work. Day. Omiii. Night. GrmB, Day. Grms. Night. Grmn. Day. Grms. Night. Grms. Day. Orms. NJght. Grms. Urinsry nitro- gen • Carbonic acid.. Water evapo- rated 7.07 403.00 454.00 6.3a 313.00 36T.00 B.91 930.00 1,425.00 6.3S 267.00 352.00 8.88 633.00 441.00 7.99 395.00 490.00 8.95 856.00 1,065.00 8.13 353.00 662.00 * The Blight difEeiences between these figures and those of the table on p. 206 are due to discrepancies in the original acconnt of the experi- ments. 208 MANUAL OF CATTLE-FEEDING. These results show, first, that the decompositions, both of protein and of non-nitrogenous matters, going on in the body are more active during the waking hours than at night, a fact which has been abundantly confirmed by other observations; and second, that the performance of muscular work during the day has practically no effect on the extent of the protein consumption, while it largely in- creases the amount of carbonic acid and water exhaled dm-ing the day. That muscular exertion causes an increased excretion of carbonic acid and water is universally acknowledged ; but, ia spite of the decisive results of Pettenkof er & Yoit, and the corroborative results of various other investigators, the fact of the constancy of the nitrogen excretion under the influence of work has been disputed. , Excretion of Gaseous Nitrogen. — That under ordi- nary circumstances no excretion of free nitrogen from the body takes place has been already shown ; but it has been sometimes claimed that in severe work a portion of the nitrogen coming from the destruction of the albuminoids is excreted in the gaseous form through skin and lungs, and that consequently the protein consumption cannot be calculated from the urinary nitrogen. According to this, the close agreement observed in the above and many other expei-iments between the urinary nitrogen on the days of rest and work is entirely accidental — a thing which is cer- tainly very improbable of itself, and which is disproved by the following considerations and experimental results. If, in consequence of work, the total protein consump- tion is considerably increased, there must be a correspond- ingly increased excretion of sulphuric and phosphoric acids in the urine ; for with every portion of albuminoid tissue destroyed, the sulphur and phosphorus which it contains MANUAL or OATTLE-FEEDIKG. 209 must be oxidized to sulplmric and phosphoric acids and finally leave the body in the urine, since these acids cannot assume the gaseous form at the temperature of the body. In the above experiments the quantity of these acids was determined in the experiments made on an average diet, and the following results obtained : Sulphuric acid. GnHB. • Phosphoric acid. Grms. Best 2.61 2.57 4.19 Work. 411 ■ The quantities in rest and work are identical within the limits of error. Kelluer's Sxperiments. — -Almost all investigators who have experimented upon this subject have obtained results agreeing in the main with those of Pettenkofer & Yoit, while most of those who have reached contrary conclusions have used palpably imperfect methods of experiment. Some late researches by Kellner * seem to indicate, how- ever, that Pettenkofer & Yoit's experiments may not cover the whole ground. In none of the experiments hitherto described was the work continued for any considerable length of time. In Volt's experiments it was confined to periods of ten minutes each, and in those of Pettenkofer & Yoit it was continued only for a few days at most, and under these circumstances caused no increase in the protein consumption. Kellner's experiments were made at the Hohenheim Experiment Station, on a horse. They included' five periods of from one to two weeks each, during each of •Landw. Jahrbuoher, VIII., 701. 210 MANUAL OF CATTLE-FEEDING. which the work perfonned per day was the same, while the amount of fodder and its digestibility did not vary essentially during the whole series of experiments. The work performed was measured by a dynamometer con- structed for the purpose, and was as follows : Period 1 475,000 kilogramme-metres. * " II 950,000 " III 1,425,000 " " IV 950,000 " " V. 475,000 " The digestibility of the food was determined directly. The following averages were obtained for the daily excre- tion of nitrogen and the total volume of the urine during the first and second halves and the whole of each period : NnsooEN IN TJbini:. Nitrogen of food.t Gnus. Volume oi Vsrss. Period. l8t half. Gnns. 2d hall Grms. Whole. Grms. let half. CO. 2d half, ac. ■Whole. CO. I II IIL.... IV. V 107.6 113.3 112.6 94.7 111.0 120.5 107.7 101.9 99.0 109.3 116.8 110.2 98.3 134.41 128.32 132.72 126.40 129.41 6,482 7,773 9,247 9,647 6,464 8,439 8,129 9,447 6,730 6,473 8,106 8,686 9,548 These results show that " an increase of the protein con- simiption went hand in hand with the increase of the work ; " but whether the former was a direct restilt of the * A kilogiamme-metre is the amonnt of force required to raise a weight of one kilogramme through the space of one metre, in opposi- tion to gravity. f Landw. Jahrbiicher, VIIL, I. Snpp., p. 77. MANUAL OP CATTLE-FEEDING. 211 latter can be decided only after a careful consideration of all the factors which may have exerted an influence npon the protein consumption. Attention has already been called to the fact that an in- creased excretion of water in the urine is accompanied by an increased excretion of nitrogen also. A glance at the table shows, however, that in these experiments the volume of the urine increased constantly from one period to an- other, and therefore cannot well have been the cause both of an increase and decrease of the ureal nitrogen. A second point to be considered is the effect of pro- longed work in altering the make-up of the body, especially as regards the proportion of fat. It has already been pointed out that muscular exertion causes an increased destruction of the fat of the body, and that this was the case in these experiments is shown by the gradual decrease of the weight of the animal during the first four periods, as follows : Aveiage weight in Period 1 1,175 lbs. " " " II 1,165 " " " " III 1,150 " " " » IV 1,119 " " "■ " V 1,140 " Since, as shown by the table, the nitrogen excretion was less than the supply, this loss of weight must have been caused chiefly by a destruction of fat consequent upon the increased work. But,, as shown in Chapter YL, the body-fat tends to di- minish the protein consumption, and, on the other hand, a loss of fat by the body would have the opposite tendency ; and we have therefore to consider whether the variations in the protein consumption here observed can be explained in this way. Obviously the increase in the first three pe- 212 MANUAL OF CATTLE-FEEDING. riods might have been due to this cause, but it was ob- served that in passing from Period III. to Period IV., and from this to Period V., the amoimt of ureal nitrogen sank at once to abou.t the average for the respective periods. Thus, in the last four days of Period III. the average daily excretion of nitrogen was 124.4 grammes, and in the first four days of Period IV., 104.8 grammes. It is easily conceivable that, on passing from a period of more to one of less work, fat should be again laid up in the body and the protein consumption thus diminished, but it is evident that such an effect would be gradual, and we cannot imagine that it should cause any such sudden change as that just mentioned. "We are consequently shut up to the conclusion that, under the conditions of these experiments, the protein consumption was greater or less according as more or less work was performed, and it would thus appear that while a moderate amount of work, like that performed in Yoit's experiments, does not sensibly increase the protein con- sumption in the body, long-continued exertion may, on the contrary, have that effect. It is of interest to note, in this connection, some experi- ments made in 1867 by T. R. !Noyes,* then a student in the Yale Medical School. His experiments were, in the main, confirmatory of Yoit's results, but in the case of one of the subjects, in whom the muscular exertion produced great fatigue and exhaustion, an increased excretion of urinary nitrogen was observed as a result of work, and the author suggests as possible that, while ordinary work does not increase the destruction of protein, exertion sufficient to produce ex- •Am. Jour. Med. Sci., Oct., 1867. MANUAL OF CATTLE-FEEDING. 213 haustion may do so. This conclusion appears to be in harmony with Kellner's results. § 3. The Source of Mubculab Poweb. Thus far we have simply been considering experimental results, without regard to the conclusions to be drawn from them. We now come to their interpretation, and here it must be admitted, at the outset, that the knowledge as yet gained is insufficient to enable us to state with cer- tainty the source of muscular power. Any elaborate discussion of the question would be out of place here, and we shall simply endeavor to present some general considerations bearing on this point, and to indicate what seem, in the present state of our knowledge, to be the most probable conclusions. Increased Oxidation of Source of Po^ver not ne- cessary. — ^At first thought the results detailed in the pre- ceding section seem to plainly indicate the non-nitroge- nous ingredients of the body as the source of muscular power, since these undergo an increased oxidation during work, while the protein does so at most only to a small ex- tent, if at all ; and ill fact many eminent physiologists hold that it is the decomposition of these bodies which supplies the energy for the production of work. But this is by no means a nscessamf conclusion. "We must distinguish between the source and the consequence of muscular exertion. The continual decomposition of matter which goes on in the living body must be accom- panied by the liberation of a, corresponding amount of force. Part of this force is set free as heat, part probably as electricity, continual currents of which circulate in the living muscle. Now it is quite conceivable that, in mus- 214 MANUAL OF CATTLE-FEEDING. cular exertion, part of this force is diverted from these channels, and takes the form of muscular contraction, while the increase in the oxidation of non-nitrogenous matter is a consequence, and not a cause, of the work. Voit, who believes the albuminoids to be the proximate source of muscular power, advances this argument, and compares the constant decomposition of protein which goes on in the body to the constant flow of water in a stream. A mill situated by the stream may use the whole power of the water, a half, a quarter, or any desired frac- tion, without in the least altering the amount of water running past. So, according to him, the decomposition of protein in the body, which is the source of power to the muscles, goes on constantly, independently of whether the energy which is set free takes the form of motion or ap- pears in some other shape. Pettenkofer & Yoit (see Chapter YII.) have shown it to be at least very probable that protein in its decomposi- tion in the body takes up the elements of water and splits up into urea andyb^y and it has been shown that 100 parts of protein might produce in this way 51.4 parts of fat. This process, now, takes place during rest, and the supposition is quite plausible that during work the protein is decomposed completely into carbonic acid, water, and urea, and that thus the latent energy which would other- wise be stored up in the fat is applied to the production of motion. It is plain, however, that this argument may be used with equal force to show that the non-nitrogenous matters of the body may be the source of muscular power. In truth these considerations simply serve to show that a study of the effects of work cannot give us decisive in- formation as to its sowrce, both because the production of MANUAL OF CATTLE-FEEDING. 215 muscular exertion does not necessarily imply an increased decomposition of the source of the power and because secondary effects may come in to vitiate our conclusions. We must, then, seek for further e\ddence. Force Value of Nutrients. — Much valuable evidence concerning the question under discussion may be gained by a consideration of the force value of food, and the ad- vocates of the non-nitrogenous matter as the source of muscular power rely largely, in support of their views, upon calculations of this sort, i. e., calculations of the amount of force that can be liberated by the conversion of a certain amount of albuminoids, fat or carbhydrates into the final products of their oxidation in the body, viz., carbonic acid, water and \area. The basis of this calculation is the amount of heat which the several nutrients evolve when burned. For example : one gramme of albumin, when completely burned, evolves a certain definite amount of heat ; the urea from one gramme of albumin likewise evolves a definite, though smaller, amount when burned. Subtracting the latter from the former, we have left the amount of heat which would be produced by the conversion of one gramme of albumin into carbonic acid, water, and urea, and this amount, by a well-known law of physics, is equivalent to a certain fixed amount of mechanical motion — that is, work. Having once obtained, then, accurate data as to the heat of combustion of each substance involved, and knowing the amount of work performed, we are able to estimate whether, in a given case, the amount of any substance or class of substances destroyed during the experiment is sufficient to set free the amount of force actually exerted. The earliest and best known experiment of this sort is 216 MANtTAL OF CATTLE-FEEDING. that made by Pick & Wislicenus,* in 1866. These ob- servers found that in the ascent of an Alpine peak (the Faulhom) the amount of protein decomposed, as measured by the urea excreted, was not sufficient, according to their calculations, to yield the amount of force actually exerted in raising their bodies to the height of the mountain, al- though no allowance was made for the work of the internal organs or for those muscular exertions which did not con- tribute to the raising of their bodies, and though the heat of combustion of protein was, in the absence of positive data, assumed to be considerably higher than it was after- ward found to be by Frankland. Here we have a perfectly definite amount of work per- formed and the most favorable assumptions made on doubtful points, and yet we have a considerable deficit of force, if the albuminoids alone are taken into account. At the time when Fick & Wislicenus made their experi- ment no data as to the heat of combustion of the nutrients were available; but shortly afterward Frankland f took up the matter and made a large number of experiments with the object of accurately determining these important quantities. His results have served as the basis for several calculations similar to those of Fick & Wislicenus, most, if not aU, of which have led to the same conclusion as did theirs, viz., that the observed decomposition of protein was insufficient to account for the amount of force actually exerted. These results, if trustworthy, show that at least a por- tion of the force exerted in muscular work must be con- tributed by other ingredients of the food than protein. * PM. Mag., XXXI., 485. t Ibid., XXXn., 182. MANUAL OF CATTLE- FEEDING. 21? No calculations seem to have been made regarding the re- lations of fat-consumption and work in this respect. Unfortunately, considerable uncertainty attaches to the very foundation on which all of these results rest, viz., the heat of combustion of protein. According to Voit, there is good reason to believe that in Frankland's experiments the nitrogenous substances, especially, were incompletely burned, and that consequently his results on these bodies were too low, and Zuntz* has shown it to be at least probable that the heat of combustion of protein as deter- mined by Frankland should be increased more than 25 per cent., and that even then it may be considerably too low. But Frankland's determinations are the only ones of this kind that we yet possess, and it is therefore evident that, until these are either proved to be accurate or replaced by others, no certain conclusions can be drawn from computa- tions of the force-value of food as to the production of muscular power, although such results as have been ob- tained on the present uncertain basis indicate strongly that the non-nitrogenous constituents of the food or body take part in the process. It may be added here that the increase in the protein- consumption observed in Kellner's experiments was not suflBcient to supply the extra force exerted in the second and third periods, even if the heat of combustion of pro- tein as corrected by Zuntz be used as the basis of the calculation. Conditions of Muscular Exertion. — If we turn from the study of the effects of muscular exertion to that of its conditions, we shall get much new light, and be helped to a more rational judgment of the theories as to its source. • Landw. Jahrbucher, VIII., 72. 10 218 MANUAL OF CATTLE-FEEDING. Presupposing the existence of a healthy and well-developed organism, we may specify ./bwr conditions as, from our point of view, the most important : 1. The facts of common experience appear to show un- mistakably that a liberal supply of protein in the food is one of the conditions of any sustained muscular exertion. Working animals must receive not only an abundance of food, but of food rich in protein, and the more severe the work, the more concentrated must be the food ; and the same fact is equally true of the human animal. This, however,. does not necessitate the conclusion that the pro- tein is the source of the power exerted : its decomposition, as we have seen, goes on independently of muscular exer- tion, and may be regarded as simply one of the conditions of the healthy activity of the muscles or of their normal nutrition. 2. The largely increased excretion of carbonic acid and water during work indicates a necessity for a liberal supply also of the non-nitrogenous constituents of food. At need, however, this demand may be supplied by the albuminoids or perhaps by fat already formed in the body. 3. An essential condition of continued activity of the muscles is the constant removal fi'om them by the circula- tion of the carbonic acid and other chemical products formed during contraction. Certain of these products, notably lactic acid and acid potassium phosphate, if allowed to accumulate in the muscle, produce the sensation of weariness and shortly incapacitate it for further action. If they be removed, either by the blood or by injection of a weak salt solution, the muscle is again capable of work ; while, if they be injected into a fresh muscle, they produce the same effect as if naturally formed there. The same accumulation of waste products goes on in the muscle after MANUAL OF OATTLE-FEEDING. 219 death, and the rigor mortis is caused by the solidification of the jelly-like viyosm, which is also one of the substances formed in muscular action. 4. A most important condition of continued muscular activity is found in the capacity which the body has of storing up within itself, during rest, a reserve of force, to be used later as demands are made upon it. After working for a certain time we experience a feeling of fatigue, or, if the exertion be continued long enough, of exhaustion, and require a period of rest before the muscles are capable of again performing work. The same thing is true of the involuntary muscles. Even those which, like the heart and the respiratory muscles, seem to work con- tinuaUy, really have relatively long intervals of rest between each exertion. Thus, the heart is calculated to be at rest for about one-third of the time. Work is only possible when alternated with periods of rest ; and while the ner- vous system has undoubtedly much to do with the need for rest, there is no doubt that it is also required by the mus- cles, to enable them to repair the waste occasioned by work. This well-known fact is sufficient to show that the force of musctdar exertion is not produced by a direct combus- tion of muscle substance by means of the oxygen of the blood, as coal is burned under a boiler, since, if this were the case, there would be no reason why it should not go on indefinitely. It is the sudden utilization of latent en- ergy which has been laid up during rest. _ That the seat of this latent energy is in the muscles themselves is shown by the fact that they are capable of contraction for a time after their blood-supply has been cut off, or even after their removal from the body. A frog's heart, when removed from the body and freed from 220 MANUAL OF CATTLE-FEEDING. all blood by injection of a weak solution of salt, will con- tinue to beat for hours, and the whole animal, under the same circumstances, moves, leaps, and behaves in short like a living animal. Agassiz relates that on one occasion he captured a shark, which fought as long and fiercely as is usual with these animals, but which, when finally se- cui-ed, was found to have its gills eaten through by para- sites, and almost all its blood replaced by sea-water. (Liebig.) In cases like these, the products of the muscular action being contiaually removed by the salt solution, etc., the muscles may continue active until their store of force is exhausted. Like a bent spring, the muscle contains a cer- tain amount of potential energy, which the will can use at pleasure ; but when the supply is once exhausted, when the spring has lost its tension, a further supply of force from without is necessary before more work can be performed. We have to consider, then, in what manner and by means of what substances this storing up of energy takes place. Storing up of Oxygen. — It would appear that the storing up of oxygen in the body which has been shown by Pettenkofer & Voit and by Henneberg (see pp. 85-87) to take place under certain circumstances, is connected with the storing up of energy. In the following tables are given the amounts of car- bonic acid excreted and of oxygen taken up in two of Pet- tenkofer & Volt's experiments which strikingly illustrate this point. The numbers in the column headed " K " are relative, and show how many grammes of oxygen appeared in the excreted carbonic acid for every hundred grammes taken up from the atmosphere. These experiments are included in the averages on p. 207. MANUAL OF CATTLE-FEEDING. 221 Atebage Diet — Rest. Carbonic acid excreted. Grms. Oxygen taken up. Grma. 6 a.m:. to 6 P.M.. 6 P.M. to 6 a.m.. 6 A.M. to 6 A.M. . 533 379 913 235 474 709 175 58 94 AvBKAGB Diet— WoKK. 6 A.M to 6 P M. , ,, ........ 8S4.6 399.6 293.8 660.1 218 6 P.M. to 6 A.M 44 6 A.M to 6 A M 1,384.3 953.9 98 It win be observed that wbile in each case more car- bonic acid was excreted by day than by night, the larger amount of oxygen was taken up during the night. More- over, the numbers in the last column show that at least a very considerable part of the carbonic acid excreted dur- ing the day must have been formed at the cost of oxygen already present in the body, since that taken up from the air during the same time was far less than the amount contained in the excreted carbonic acid. A comparison of the two experiments also shows that of the increase of the carbonic acid excretion caused by work (372.2 grammes), by far the larger part (351.6 grammes) occurred during the hours when the work was performed, while the oxygen taken up during the same time increased only 58.8 grammes, against 186.1 grammes in the following night- 222 MANUAL OF CATTLE-FEEDING. Further experiments by the same investigators, while not always yielding as striking results as did these two, confirmed in the main the conclusions drawn from them. It was found, it is true, that the storing up of oxygen did not always take place by night, as in these experiments ; but the fact that oxygen may be retained in the body in considerable quantities was fully established. One other important point was observed in Henneberg's earlier experiments on this subject, viz., that the greatest storing up of oxygen took place in those experiments in which the fodder was richest in albuminoids. These experiments extended over only twelve hours, corresponding to the " day " half of Pettenkofer & Yoit's experiments, and in almost every case it was found that the carbonic acid excreted contained more oxygen than was taken up by the body during the same time, thus show- ing a formation of carbonic acid at the expense of oxygen previously stored up. The following summary of the re- sults shows that this excess of oxygen was, in general, greatest in those cases where most albuminoids were fed : Number of Experi- ment. Protein of fod- der. I.lw. Oxygen taken np. T,hs Oxygen in car- bonic acid. Batio of the two. 1 0.79 4.25 5 42 1 :1.28 2 0.82 2.63 4.34 1:1.65 3 0.80 3.20 4.65 1:1.45 5. 0.89 3.83 6.01 1 :1.57 6 0.78 5.20 6.67 1:1.28 7 2.60 3.00 7.13 1 : 2.38 8 3.51 3.40 7.63 1 :2.24 MANTJAL OF CATTLE-FEEDING. 223 Tills alternate storing up and giving off of oxygen by the body has also been observed in physiological experi- ments of an entirely different character, which can only be alluded to here. That the storing up of energy is connected with the storing up of oxygen is indicated by a few experiments by Pettenkof er & Voit on two diseases in which the patient is almost incapable of muscular exertion, viz., diabetes and leulcsemia. In these experiments the total excretion and the total amount of food were not much different from those in health ; but there was no such storing, up of oxy- gen as in the healthy organism, and there was also, as is usual in these diseases, an almost entire lack of strength. But Pettenkofer & Voit's and Henneberg's results are especially valuable for our present purpose because they show that muscular power does not have its origin in a simple oxidation but in the "explosive" decomposition, independently of oxygen, of material already prepared in the muscle, a conclusion to which we are also led by the fact, already noted, that the muscle is able to perform work for a considerable tune independently of oxygen, provided the resulting decomposition products are re- moved. Conclusions. — ^We have learned in the foregoing pages that, presupposing the existence of a healthy and well- nourished organism, muscular exertion is possible when the chemical products of the action are removed from the muscles, and when the body has had the ability and op- portunity to lay up a store of latent energy ; that this stor- ing up of energy is effected by the entrance of oxygen from the air into combination with the organic substances of the muscles ; that when work is performed this oxygen reappears in combination with carbon and hydrogen as car- 234 MANUAL OF CATTLE-FEEDING. bonic acid, water, and other products ; that this process re- sults in an increased excretion of carbonic acid and water, while the excretion of nitrogen remains, in most cases at least, unaltered ; and finally, that the amount of work per- formed is in many cases greater than can be accounted for by the amount of protein which the urinary nitrogen shows to have been decomposed. All these facts are well ascertained, and they enable us to frame an hypothesis which, though confessedly but a rough and approximate one, is still considered by many high authorities to accord more closely with the facts of the case and with our general conceptions of vital activity than those which place the source of muscular power in protein on the one hand, or non-nitrogenous matters on the other. This hypothesis supposes that during rest some of the substances of the muscle-cells decompose into simpler com- pounds, and in so doing set free their latent energy, and that this energy, instead of appearing as heat, etc., is used to build up out of other constituents of the cell a still more complex compound, containing more potential energy than its components, just as one portion of society may acquire wealth at the expense of another portion without increas- ing the total wealth of the community. The substances which are thus " synthesized " are pro- tein, non-nitrogenous matter from the blood, and oxygen. The hypothetical compound thus formed, after accumulat- ing to a certain extent, decomposes during rest as rapidly as it is formed. When the muscle is called on to perform work, however, it splits up rapidly, yielding carbonic acid, water, and other non-nitrogenous matters, and a nitro- genous compound, and giving forth the amount of force "which was required to form it. The non-nitrogenous sub- MANUAL OP OATTLE-FEEDINa. 225 stances which are formed are supposed to be rapidly ex- creted, while the nitrogenous product, instead of undergo- ing further decomposition, is used over again to re-form the hypothetical substance. This view has much in its favor. Yarious syniiieses, more or less like that above outlined, are known to take place in the body ; and, moreover, we have seen that all the facts seem to indicate that muscular force originates in a splitting up of some substance in the muscle, rather than in any process of oxidation in the ordinary sense of the word. The hypothesis explains the object of the storing up of oxygen in the body during rest, and its connection with the laying up of a reserve of force : the oxygen enters into the supposed complex compound much as the nitric-acid radicle enters into nitro-glycerine or gun-cotton — it is held in a state of unstable equilibrium, ready to enter into new and simpler relations with its neighboring atoms and to set free the force by which it was placed in its unstable position. The hypotliesis also brings that necessity for albuminoids in the food of the laboring animal which practical experience has shown to exist, into harmony with the fact that there is no greater excretion of nitrogen dur- ing work than during rest. Furthermore, it shows why we need rest after work. In the first place, the circula- tion must have an opportunity to remove those waste products which accumulate in the working muscle faster than they can be carried off, and in the second place a fresh supply of force must be stored up in the way des- cribed before it is ready to be used at the command of the wiU. Finally the assumption of a complex " contractile mate- rial" is in harmony with the results obtained by Fick & 10* 226 MANUAL OP CATTLE-FBEDIITG. Wislicenus and others regarding the force Talne of the nutrients, since it does not place the source of muscular power in the albuminoids alone biit in the joint action of these and of non-nitrogenous matters. It is possible that Kellner's results, if confirmed by further investigation, may modify this hypothesis some- what. They at least suggest that when, under the influ- ence of protracted work, the reserve of " contractile mate- rial " runs low, the protein of the muscle may be used to supply the deficiency. In any case, it must be remembered that this hypothe- sis is only a provisional one. Much work remains to be done before we can have a full understanding of this im- portant subject, and the chief value of such an hypothesis as this is to co-ordinate and arrange our knowledge, and serve as the basis for further research. § 3. Ikteknal Wobk. In the two previous sections we have been considering one particular form of work, viz., muscular exertion. As pointed out at the beginning of this chapter, there are other forms of work which, though less obvious, are of equal or even greater importance, and we now turn our attention to these, grouping them under the convenient, if not strictly accurate, name of internal work. The internal work of the body may be of three princi- pal kinds : muscular work of the internal organs, produc- tion of heat, and of chemical changes. Muscular Woek of Internal Organs. — The activity of many of the most important internal organs involves considerable muscular action, e. g., in the heart, the respi- ratory muscles, and the digestive apparatus. Of these, MANUAL OF CATTLE-FEEDING. 227 the work of the two former is tolerably constant, and makes pretty uniform demands on the latent energy sup- plied by the food, while the labor performed by the di- gestive apparatus is more variable, being relatively greater with a bulky than with a concentrated fodder, and is like- wise greater at or near the time of feeding than at other times. 'Henneberg's Experiments. — ^We have already learned that muscular exertion increases the excretion of carbonic acid, but not notably that of urea. Henneberg * has shown that the same is true of the work of the digestive organs, so far, at least, as the excretion of carbonic acid is con- cerned. In one series of respiration experiments on sheep the animals were fed chiefly during the day, while in a second series they received most of their fodder in the night. The numbers in the following table give in grammes per day the results obtained on two sheep taken together : Febdiko chiefly bt Day. Number of Experl- FODBEB (Hay). Cabbosio Acid. Of 100 Pabts Cabbomio Aoid. Day. Gnna. Night. Gems. Day. Qrms. Night. . G-rms. Day. Per cent Night. Per cent. 1 and 3 1,809 1,834 1,736 634 684 733 877 777 864 756 691 715 54 53 55 46 3 and 4. 47 45 Average 1,790 677 889 731 54 46 • Nene Beitriige, etc. 1871, p. 157. 928 MANUAL OP CATTLE-FEEDINO. Feeding chiefly bt Night. Number of Experi- FODDSB (Hat). OABBomc Aom. Op 100 Pabts Cabbonio Aoid. ment. Day Grma. Night Grme. Day Grms. Night GnnB. Day. Per Cent Night Per Cent. lands 590 653 586 1,685 1,588 1,499 719 706 693 806 843 815 47 46 46 53 3 and 4 54 5 and 6 54 Average 610 1,591 706 831 46 54 The increased work caused by the feeding by day in one case, and by night in the other, resulted immediately in an increased excretion of carbonic acid. It is probable that the difference observed in these ex- periments is chiefly the expression of the amount of work involved in chewing and rumination, since the alimentary canal always contains more or less fodder; but at the same time it gives us a useful hint of the amount of work required in the digestion of the bulky fodder of herbivorous animals. Saving of Work by Concentrated Fodder. — A cer- tain amount of work by the digestive organs is, of course, necessary and unavoidable, but it is evident that the amount of this work will be reduced by the use of as concentrated fodder as possible. That is, the less the proportion of indigestible matters contained in a fodder, the less of the fodder wiU have to be eaten and worked over by the animal in order that it may obtain the amounts of the several nutrients which it MANUAL OF CATTLE-FEEDING. 229 requires. If we could eliminate the indigestible matters entirely from the fodder of an animal, we should effect the greatest possible economy of work by the digestive organs, and could produce an equal nutritive effect with a correspondingly smaller amount of digestible nutrients, since, as explained on p. 203, the production of work of any kind implies a destruction of the constituents of the body, which loss must finally be supplied by the food. Such an extreme case is purely suppositious, but obviously, the nearer we approach to it by the use of fodders contain- ing a large proportion of digestible matter, the gi-eater wiU be the saving of work, although we have no accurate data regarding the amount of the saving which could thus be made. In Miller's system of exclusive meal-feeding, it is probable that a portion, at least, of the saving in fodder is due to the less amoimt of work imposed on the digestive organs. ■In practice, however, considerations of profit come in to modify the conclusions just drawn. As a general rule, a given number of pounds of digestible matter can be had more cheaply in the form of coarse fod- der, such as hay, straw, etc., than in the more concentrated fodders, like the grains, which contains less indigestible mat- ter. Moreover, ruminating animals are adapted by nature to extract the nutritive matters from coarse fodder as com- pletely as possible, so that it is obvious that under some circimistances it may_be more profitable to feed almost exclusively coarse fodder (in wintering stock, for example), while in other cases, e. g., fattening, where a rapid produc- tion is desired, the greater cost of concentrated fodders may be more than covered by the economy of digestive labor and the consequent saving of material which they cause. PBODtrcnoN OF Heat. — The continual chemjcal changes 230 MANUAL OF CATTLE-FEEDING. going on in the body, like similar changes outside the body, giye rise to a liberation of heat. Indeed, all the force conveyed to the body by the food leaves it either as motion or heat, all the actions of the internal organs, all the molecular labor of the nervous and other tissues, etc., being finally converted into heat. It has been estimated by eminent authorities that, in man, of the total energy represented by the food, from four-fifths to five-sixths takes the form of heat. This production of heat, of course, implies a corresponding consumption of food-material, just as the production of heat in a stove implies the con- sumption of fuel ; so that it is evident that any change in the amount of heat set free has a direct effect on the de- mands of the body for food and on the results of feeding. Viteil Heat. — ^The bodies of warm-blooded animals (birds and mammals) maintain a very constant temperature at all times, in spite of great variations in the temperature of their surroundings. The production of vital heat, as it is called, by the oxidation of food-elements, and the losses of it to which the body is subject, are so balanced as to result in keeping the temperature of the body at from 95° to 104° F., a variation of more than a de^ee or two from the normal temperature of an animal iadiCating serious dis- turbance of the organism. This regulation of the vital heat appears to be effected in two ways : first, by variations in the loss, and second, by variations in the production. The chief sources of loss of heat by the body are : 1. Conduction and Eadiation from the Skin. 2. Evaporation of Water from the Skin and Lungs. 3. Warming of the Ingesta (Food and Drink). These we will take up in their order and consider how in each case the balance of the vital heat is kept up. MANUAL OP CATTLE-FEEDING. 231 Conduction and Radiation from the Skin. — This is one of the principal sources of loss of heat by the body, and also the one which is most susceptible to regulation. Henne- berg,* in his respiration experiments on sheep, already cited, estimates that the total amount of heat produced by the animals experimented on was applied as follows : To waiming the ingesta 40 per cent. • " " " Inspiredair 4.2 " " eTapoiation of water 26.7 " " Bupply loss by zadiation, eto 65.1 " Experiments on man have given very similar results. Plainly, the greater the amount of blood passing through the vessels of the skin, the more heat will be lost, while, on the other hand, a diminution in the current of blood will check the loss of heat. Now when the skin is exposed to cold, as, for example, to cold air or to the water of a cold bath, the capillaries of the skin are contracted and the blood-vessels of the vis- cera expanded, thus diverting a portion of the blood from the former to the latter and sometimes causing a rise of temperatiu-e in the interior of the body. Conversely, imder the influence of warmth the capillaries of the skin dilate, admitting more blood, and thus effecting a cooling of the latter. To this is to be added the loss of heat by the evaporation of the perspiration, to which atten- tion will be called on subsequent pages. In this manner the loss of heat from the surface of the body -is regulated in accordance with the external tem- perature, but there are numerous experiments which show that under such circumstances the 'prodMCtion of heat also varies, though we have but little knowledge of the • Neue Beitrage, etc., 1871, p. 227. 232 MANUAL OF CATTLE-FEEDING. means by which these variations are effected. It has been shown by mimerous observations on rabbits, guinea- pigs, and cats that, in warm-blooded animals, exposure to cold largely increases both the consumption of oxygen and the excretion of carbonic acid, thus showing a greater activity of the chemical processes in the body and pre- sumably an increased production of heat, while warmth, on the other hand, has the converse effect, diminishing the amount of cheniical change in the body. The following selection from the results obtained by Theodor * in an extensive series of experiments on a cat will serve to illustrate these facts. Each experiment lasted six hours. Temperature. Deg. Cenc Carbonic acid excreted. Grms. Oxygen taken up. Grms. Temperature. Deg. Cent. Carbonic acid excreted. Orms, Oxygen taken up. Grms. ' -5.5 -3.0 +0.3 +5.0 19.83 .18.42 18.24 17.90 17.48 18.36 19.95 14.83 +13.3 +16.3 +30.1 + 39.6 17.63 15.73 14.34 13.12 17.71 14.74 13.78 10.87 In some of these experiments considerable motion on the part of the animal took place, which may have influ- enced the result, and Yoit f therefore executed a series of similar experiments on a man. The man weighed about 156 lbs., and, after having been exposed for some time to the temperature whose effect was to be observed, passed six hours in the respiration apparatus fasting and iir com- plete rest. In this time he excreted the following quanti- ties of carbonic acid and nitrogen : • Zeit. f. Biologie, XIV., 51. t Ibid., XIV., 57. majstual of cattle-feeding. 233 Temperature. Deg. Cent. Carbonic aoid. Grma. treal nitrogen. Grms. Temperature. Deg. Cent. Carbonio acid. Grms. Ureal nitrogen. Grms. 4.4 210.7 206.0 192.0 155.1 158.3 4.23 4.05 4.20 3.81 4.00 28.7... 24.2 26.7 30.0 164.8 166.5 160.0 170.6 3.40 6.5......... 3.34 UO 3.97 143 16.2 The increased excretion of carbonic acid in the cold as compared with an ordinary temperature of 14° to 15° C. (about 60° F.) is as marked in these experiments as in the preceding ones, but above that temperature a slightly in- creased excretion was observed. The excretion of nitrogen is seen to vary in the same way, though to a small extent, indicating an increased protein consumption as a result of exposure to a low temperature. These results show plainly how great an influence the temperature of its surroundings may have on the amount of fodder required by animals, and confirm the conclusion drawn from many practical experiments, that it is desirable to protect animals from extreme cold. In conclusion, it should be said that the action of a low- temperature of the surrounding medium appears to be, in the first place, on the nerves, and that only through them does it cause a greater activity of the chemical processes in the body and an increased production of heat. It has been shown by Pfliiger that when this action of the nerves is hindered, the activity of chemical change in the body is increased by heat and decreased by cold, just as many chemical processes outside the body are, and as is the case normally in cold-blooded animals. 234 MAX0AL OF CATTLE-FEEDING. Evaporation of Water. — ^An important regulator of the temperature of the body is the evaporation of water, especially from the skin. In the conversion of any liquid into vapor, a very con- siderable amount of heat is absorbed, and becomes latent in the vapor. This absorption of heat during vaporization may be rendered evident to the senses by wetting the hand with some volatile liquid, such as alcohol or ether, and moving it through the air to hasten evaporation. In the same way, the evaporation of water from the skin, which is constantly going on, cools the latter ; and though the effect is less noticeable than with a more volatile liquid, on account of the greater slowness of the evaporation, the total amount of heat thus abstracted from the body is very considerable, amounting, according to Henneberg (p. 231), in the case of sheep, to nearly 2Y per cent, of the total loss of heat. The conversion of one gramme of water at the tempera- ture of the body into vapor of the same temperature requires 580 heat units, an amount equal to that produced by the combustion of 0.148 grammes of organic matter having the composition of starch, and corresponding to an excretion of 0.241 grammes of carbonic acid. In the ex- periments by Henneberg just mentioned, the average daily excretion of water from lungs and skin was 881.7 granomes, which, according to the above figures, required for its evaporation as much heat aS would be produced by the combustion of 130.5 grammes of starch, while the average amoimt of carbhydrates digested per day was 464.3 grammes. Consequently, if the loss of heat by evapora- tion was supplied by the combustion of these substances, about 28 per cent, of them was thus consumed. Such results as this, of which many might be cited, show MANUAL OF CATTLE-FEEDING. 235 tis plainly both the importance of the process of evapora- tion as a regulator of the vital heat, and the great waste of fodder that may be caused by an undue increase in the perspiration. The regulation of the temperature of the body by the perspiration, especially the sensible perspiration (sweat), is too familiar to require more than a simple mention ; but the effect of increased perspiration in augmenting the ex- cretion of carbonic acid is of greater importance for our present purpose. This effect is shown in these same ex- periments by Henneberg. In the following table his results are arranged according to the amount of carbonic acid excreted. The numbers refer to the two animals taken together : Tempera- ture of stall. Deg. Cent. Hay fed. Grms. Water dnmk. Grma. Carbonic acid excreted. Grms. Water evaporated. Grma. Urinary nitro- gen. Grms. 9.3 12.7. 14.1 13.6 13.7. 13.7. 2,508 2,085 2,275 3,241 2,459 2,443 2,757 (?) 3,193 (?) 3,038 3,876 1,468 1,508 1,535 1,548 1,579 1,633 1,368 1,578 1,601 1,680 1,750 1,650 14.81 15.42 16.91 15.59 15.56 16.03 It is evident at once that in every case but the last an increased evaporation of water and an increased excretion of carbonic acid accompany each other ; but whether the latter is a result of the former can be determined only after the possible influence of all the other factors which influence the excretion of carbonic acid has been consid- 236 MANUAL OF CATTLE-FEEDING. ered. These are, in this case, the amount of foodj the amount of water drunk, and the temperature. That the amount of food has an important influence on the amount of carbonic acid excretied is a well-established fact, and is well illustrated by a seventh experiment on the same two sheep, in which all food was withheld for a single day. The carbonic acid excretion sank at once to 837 grammes, or scarcely more than half that previously ob- served. In these six experiments, however, although the amount of fodder eaten varied somewhat, no connection can be traced between its amount and that of the carbonic acid. The same "is true of the amount of water drunk, whUe the lowest temperature {i.e., the one which should cause the greatest activity of the oxidations in the body) coin- cides with the minimum of carbonic acid. We must therefore conclude that there is a connection between the carbonic acid excretion and the evaporation of water, and that an increased evaporation causes more material to be oxidized in the body, in order to make good the resulting loss of heat. Henneberg's experiments are the only ones which we yet possess on this important subject, but they suffice to show its practical importance and the desirability of fur- ther experiments in the same direction. A direct influence of the amount of water evaporated upon the protein consumption does not seem to be indi- cated by these experiments. Warming Ingesta. — ^A considerable quantity of heat (according to Henneberg, about 4 per cent.) is consumed in raising the food and drink of an animal to the temperature of its body. Of this amount, by far the larger part is used in warming the water of the ingesta, both on account MANUAL OF OATTLE-FEEDtNG. 237 of its large amount and because a greater quantity of heat is required to increase the temperature of a pound of water one degree than is sufficient to effect the same change in a pound of any other substance. The effect of excessive drinking on the production of flesh and fat has already been mentioned in the two pre- ceding chapters, and there can be little doubt that a part, at least, of this effect is due to the demand for heat thus made on the system. The last line of the table on p. 235 affords an illustra- tion of the influence of the amount of water drunk on the excretion of carbonic acid. Although the quantity of water evaporated is less than in the two preceding cases, miore carbonic acid is excreted, evidently on account of the considerably larger amount of water drunk. It is notice- able that the urinary nitrogen in this experiment is also more than in most of the others. Further examples of the influence of the quantity of water drunk upon the decomposition of matter in the organism might be given, but the few results which have as yet been reached in this direction, while they afford im- portant practical hints, are still so meagre that no very ex- tended conclusions can be based on them. Practical Conclusions. — In the foregoing pages we have seen that the production of heat makes large demands on the food supply of an animal, and that various circum- stances may influence the amount of heat produced and thus effect an economy or a waste of fodder. There re- mains to be considered the practical application of these facts to the feeding and care of cattle. Temp&ratwre of Stable. — ^It is evident that the warmer the air of the stable is kept the less heat the animals will lose by radiation, and consequently the greater will be the 238 MANUAL OP CATTLE-FEEDING. saving of fodder effected. If this were the only circum- stance to be considered, the greatest economy would result from keeping the surroundings of the animal at the same temperature as its body, for then no heat would be lost by radiation. A high temperature, liowever, tends to increase the per- spiration, which, as we have learned, demands considerable heat for its evaporation ; so that the saving effected by the diminished radiation consequent on a high temperature may be more than counterbalanced by the loss due to the greater amount of perspiration evaporated. To this is to be added the fact that the animals are also led to drink more water, thus still further increasing, or tending to in- crease, the consumption both of protein and fat in the body. It thus becomes evident that the most favorable balance between these two opposing factors, and consequently the most economical production, may take place at a medium temperature, and this conclusion is one which accords with the general experience of farmers. That the least expenditure of material by the body takes place at a medium temperature is very clearly shown by Yoit's experiments, cited on p. 233. Finally, the question of profit comes in. Warming the stable in winter involves a certain amount of expense; leaving it cold also involves a certain amount of expense, viz., the cost of the excess of fodder required by the ani- mals. It is a question to be settled by the circumstances of each particular case which method of procedure is, on the whole, more profitable. Amount of Drvnk. — As already pointed out, excessive drinking tends to increase the consumption of matter in the animal body, and thus to decrease the profits of the MANUAL OF CATTLE-FEEDING. 339 feeding. It therefore becomes the interest of the feeder to restrict the amount of water drunk by his animals to that required for health. This is estimated by Wolff at four pounds per pound of dry matter of the fodder for cattle, and two pounds for sheep, this amount including that present in the fodder. The more watery the fodder the less drink is necessary. Naturally, the amount of water drunk will, in most cases, be left to the instinct of the animal, and regulated only by avoidance of those conditions which, like too large rations of salt, too high temperature of the stable, etc., in- crease the desire of the animals to drink. Finally, there is no doubt that it would be advantageous, when practicable, to supply animals with water warmed at least somewhat above the freezing temperature, since it would seem that at least one chief object of the increased protein and fat consumption caused by excessive drinking is to produce heat to warm the water to the temperature of the body. StiU more is it desirable, in the wintering of stock, not to compel them to satisfy their thirst with snow or ice, since not only must these be warmed, but they must be mdted, and the conversion of one pound of ice at 32° F. into water of the same temperature requires somewhat less than twice the amount of heat needed to warm one pound of water from 32° to the temperature of the body. All this heat comes directly from the combustion of tissue, and is just so much subtracted from the net results of feeding, and consequently from the feeder's pocket. Cooking Fodder. — A portion of the advantage frequently claimed to result from cooking and steaming fodder un- doubtedly arises from the fact that the fodder is eaten while still warm, and that thus a certain amount of the sub- 240 MANUAL OP CATTLE-FEEDING. stance of the animal, which would otherwise be burned in wanning the food, is rendered available for other purposes. This fact, in connection with the increased palatability of the fodder and the consequently greater consumption of it, probably explains the favorable results frequently ob- tained by means of this practice, and at the same time renders it evident that its profitableness must depend on circumstances. Under some conditions, the gain thus effected might repay the expense, while under other con- ditions it might be more economical to let the cattle warm their ovm food. Pboduotion of CHEMtcAL CHANGES. — The food being, as already explained, the means by which supplies of force are introduced into the body, it is evident that any change taking place in the constituents of the food before they become part of the body by which any of the force which they contain is liberated, involves an equivalent loss to the organism. It is as if the fuel which is to drive the engine were partially burned before being put imder the boiler. Such changes actually take place in the food to some ex- tent during digestion. For example, we have all along assumed that the carbhydrates yield grape-sugar in the alimentary canal, and all calculations of rations are based on that assumption. In the main it is probably correct ; but it is known that portions of these bodies suffer still further decomposition and yield lactic acid. In this pro- cess some of the latent force of the carbhydrates appears as heat, and the resulting lactic acid and other products are less valuable to the body by just the amount of force thus liberated. It was stated on page 64, that many good authorities con- sider that the digestion of cellulose consists essentially in MAKTTAL OF OATTLE-FEEDINa. 241 a kind of fermentation. Little is known of this process, but it ia.not improbable that the small quantities of marsh-i gas and hydrogen exhaled by ruminants have their source in it, and this fact indicates that a considerable part of the latent energy of the cellulose is liberated during its diges- tion. This raises the question whether the various carbhy- drates are equally valuable as nutrients — a question which has, as yet, received scarcely any attention. Their equiva- lency has been assumed and made the basis of the calculation of rations, simply because, in the lack of aU evidence, this was the only practicable method. It is quite probable that this assumption does not involve any very great error, except, perhaps, in the case of cellulose ; but the actual comparative value of these substances can be determined only when we know, first, how mxieh latent energy each contains, and, second, how much of this energy is liberated during digestion. This is, of course, equally true of the other classes of nutrients ; * but the study of this subject can hardly be said to have begun, and the only object of mentioning it here is to show how provisional are our present methods of estimating the value of fodders, and to guard the reader against the error of considering them final and conclusive. They are of great value and have rendered very important service ; it is certain that they are not grossly erroneous. At the same time, no good and much harm may come from an unintelligent overestimate of their accuracy and value. The so-called synthetic chemical actions (that is, forma- * The few results which have been obtained on the albuminoids will be mentioned in another connection. They indicate that the vegetable and animal albuminoids are practically equivalent. 11 242 MANUAL OF CATTLE-FEEDING. tions of complex substances from simpler ones), of which many have been shown to take place in the body, also de- mand a supply of force for their performance. Thus the production of the true " contractile substance " of the muscles (see p. 224), if such a substance exists, from pro- tein and non-nitrogenous matter, must absorb and render latent large amounts of force coming from the simultaneous oxidation of other materials. Such processes, however, have no significance to the feeder, since the force thus rendered latent is not with- drawn from the body, but is set free again in it when the complex substance is decomposed. IxFLiTENCE OF STIMULANTS. — The influence of stimulants upon the chemical processes in the body has been but little investigated. Voit's experiments on coffee * seem to indicate that this substance, at least, has practically no effect upon the pro- tein consumption in the dog. On the other hand, it would seem that the oxidation of non-nitrogenous matters may be considerably affected by nervous influences, such as cold, stimulation of the skin, light, sound, etc. The fact that the excretion of carbonic acid is less during sleep also points in the same direction. There appear to be no experiments on farm animals "ouching this point, but we may safely conclude from the ^^cts known concerning other animals, as well as from practical experience, that nervous excitement, produced by rough treatment, noise, etc., is unfavorable to the best results of feeding. * " Unteisnchungen liber den Einflnss des KochBalzes, Kaffee's, etc., auf den StoflEwechBel." PAET II. THE FEEDING-STUFFS. CHAPTER I. DIGESTIBILITY. A suBSTAiTCE 18 Said to be digestible if, -when eaten, it can either be taken up directly by the absorbent vessels of the stomach and intestines, or is capable of being altered by the digestive fluids into substances which can be thus resorbed. The pure nutrients (except, perhaps, cellulose) may be considered to be wholly digestible, thus justifying their name, but as they occur in feeding-stuffs various circumstances conspire to prevent their entire digestion. In the first place, as has already been more than once pointed out, our methods of fodder analysis are very im- perfect, and serve only to divide the substances contained in the fodder into groups of more or less similar matters. All the nitrogenous matters are — or have hitherto been — included under the albuminoids, all the substances soluble in ether under fat, etc., while the nitrogen-free extract, being determined by difference, includes everything not 244 MANtJAL OF OATTLE-FEEDING, belonging to the other four classes. It is evident that, be- sides real nutrients, each of these groups of substances may include many things which are wholly indigestible, and hence that, although pure protein, for example, may be wholly digestible, the " crude protein " of hay or straw may be only partially digestible, as is actually the case. Furthermore, a substance which of itself is entirely di- gestible -may be so enclosed in indigestible matters as largely or entirely to escape the action of the digestive fluids. For example, seeds which are swallowed whole gener- ally escape digestion, in spite of the fact that they consist largely of digestible matters, because their hard outer coat- ings shut up the latter in an impervious shell. Similarly, i£ the walls of a single cell are so hard and woody as to be unacted on by. the juices of the alimentary canal, the con- tents of the cell may pass through the animal without being digested. Finally, the relative quantities of the several nutrients in the fodder of an animal have a mutual influence on the amount of each digested. Thus, if a fodder be made over- rich in starch, the digestibility of the albuminoids is de- creased, and, at the same time, a portion of the starch escapes digestion. All these considerations render it obvious that a simple analysis is not sufficient to determine the value of a feed- ing-stuff, but that the digestibility of its constituents must be taken into account, either by direct experiment or by reference to the results of previous experiments. In this chapter we shall consider such general principles as experiment has established regarding the digestibility, first, of coarse fodder, and second, of the concentrated bye-fodders, under the influence of various conditions, and MANUAL OF CATTLE-FEEDING. 245 in the following ones take up in detail the properties and digestibility of the more important feeding-stuffs. In this connection it is important to distinguish between digestihility and ease of digestion. By the digestibility of a feeding-stuff, or any ingredient of it, we mean the extent to which it is digested under ordinary conditions. If, in a digestion experiment, one- half of the crude protein of a certain feeding-stuff is di- gested, we express the digestibility of that nutrient by the number 60^ — that is, 50 per cent, of it was digested. If the digestibility of the crude fibre of a certain sample of hay is said to be 40, it means that 40 per cent, of it was digested. These numbers, expressing the percentage of the several nutrients of a fodder which is digestible, are called digestion coefficients. In general, a high digestibility will naturally accompany easy digestibility, but this may not always be the case, and the two conceptions are entirely distinct. § 1. DiOKSTIBILITY OF THB NUTRIKNTS OF COABBB FODDBK. By the term " coarse fodder " we designate the various kinds of grass, hay, and straw, corn-fodder, stover, and, in short, all kinds of forage, whether fed green or dry. Coarse fodder commonly consists of the stalks and leaves of the plants, and is rich in woody fibre. Under ordi- nary circumstances it forms the bulk of the fodder of farm-animals, with the exception of the hog. In this section we shall consider the digestibility of thej several nutrients of coarse fodder when this is fed exclu- sively, taking up subsequently the influence of the quality of the fodder and of the presence of concentrated bye-fod- ders on the digestibility of the ration. 246 MABTTAIi OP CATTLE-FEEDING. The Weende Experiments. — ^The foundations of our knowledge of the digestibility of feeding-stuffs were laid by tbe labors of Henneberg & Stobmann, at the Weende Experiment Station near Gottingen. Their experiments began in the year 1858, and in 1860 they published their first results, under the title " Beitrdge zwr Begrimchmg einer rationellen Futterung der Wiederk&uer" of which a second volume appeared in 1863-64. Further experi- ments were made in 1863-64 by G. Kiihn, H. Schuke and Aronstein,* under Henneberg's direction, and in 1865 by Henneberg.f All these experiments were made on mature oxen, and gave results regarding the digestibility of feeding-stuffs, particularly of coarse fodder, which subsequent investiga- tions on these and other animals have served only to con- firm, while they still form the basis of our feeding stand- ards for oxen. To these same investigators is likewise due the credit of developing and perfecting methods of experiment adapted to such researches, and which can hardly be said to have existed before, so that the Weende experiments may be considered to mark the beginning of a new era in the science of feeding. Since their publication innumerable feeding experiments have been made, involving determinations of the digesti- bility of various feeding-stuffs, the results of which, in all important points, have been the same as those reached in Weende. It is far beyond the scope of this work to give even a partial account of these experiments, and we must content ourselves with selecting a few results to illustrate each point as it is brought up. * Jour. f. Landwirthschaft, 1865, p. 383 ; 1866, p. 269, and 1867, p. 1 t Neue Beitirage, etc., Heft 1, p. 287. MANUAI. OP OATTLE-FEEDING. 347 Crude Fibre Digestible. — ^As has been already stated in a preceding chapter, a portion of the crude fibre of coarse fgdders is digestible. This fact is so well ascer- tained, and has been so uniformly observed, that no special proofs of it need be brought forward here. The amount digested varies, according to the quality of the fodder and other circumstances, from 25 per cent, to as high as 70 per cent, of the totial quantity. The ruminants, in particular^ have the power of digest^ ing large amoimts of crude fibre, a power due, doubtless, to the great extent of theii- alimentary canal and the length of time during which the food remains in it. They are hence especially adapted to the consumption of coarse fodder, such as hay and straw, and can extract from it considerable quantities of nutrients, while the horse stands considerably below them in this respect, and the hog seems, like the carnivorous animals and man, to be able to digest only young and tender fibre, such as is found in roots and in young and juicy green fodder. The Digested Portion is Cellulose. — -The "crude fibre" obtained in analysis is a mixture of cellulose and " liguin," but the digested portion has been shown to con- sist of cellulose only, which has exactly the composition of starch (p. 39) and therefore is assumed to have the same nutritive value as the latter.* This fact has been deduced by a comparison of the ele- mentary composition of the crude fibre of the fodder and of the excrement, as in the following example — an experii ment made at "Weende in 1860-61. The fodder was wheat-straw, and 52 per cent, of its crude fibre was digested, while 48 per cent, was found in * Compare page 241. 248 MANUAL OF CATTLE-FEEDINO. the excrement. The original crude fibre of the fodder and that of the excrement had the following composition re- spectively : Poflder. Kxcrement. (^■xrhon , 45.4 6.3 48.3 48 1 6.8 45.1 100.0 100.0 The following calculation gives us the composition of the digested portion : Carbon. Hydrogen. Oxj'gen. In 100 parts of cmde fibre of fodder. . . 45.4 6.3 48.3 " 48 " " " di7TiB.... 23.09 3.26 21 65 Difference = 52 parts of digested cmde fibre 22.31 42.9 3.04 5.7 26 65 In 100 parts of digested crude fibre. . . . 51.4 " " ceUnlose 44.4 6.2 49 4 The above numbers are simply intended to illustrate the method of calculation ; in other and later experiments a much closer correspondence with theory has been obtained. For example, the average of eleven experiments made in Weende in 1863-64:, on various kinds of coarse fodder, and with every precaution, was the following, which corresponds as closely as can be expected in such experiments with the composition of pure cellulose : MANUAL OP OATTLE-FEEDING. 249 Carbon. . . Hydrogen. Oxygen. . . In these experiments the true cellulose in fodder and excrements was determined by a method proposed by F. Schulze, and from the data thus obtained the absolute amounts of cellulose digested in each experiment were cal- culated. The results were practically identical, as the fol- lowing table shows, with the amount of crude fibre digested, thus furnishing another proof that the latter con- sisted of cellulose. No. ol Experiment Crude fibre aigeated. Oellulaae digested. Lbs. Difterence. TAB. 1 2.01 1.91 3.93 4.63 4.81 4 37 4 38 3.12 3.16 3.87 4.47 4.55 4.03 4.13 + 0.11 2 + 0.35 4 , -0.05 5 -0.16 6 -0.36 7 .. .... -0.35 8 -0.35 By no means the whole of the cellulose of coarse fodder is digested, but its percentage digestibility is consider- ably greater than that of the ** crude fibre." Nitrogen-free Extract. — While a part of the crude fibre is always digested, especially by ruminants, a part of the so-called nitrogen-free extract, on the other hand, is 11* , '. 250 MANUAL OP CATTLE-PEEDIIira. not digested, or is at least, even if present in an easily soluble form, not resorbed, but excreted with the dung. Compensation. — It is a noteworthy fact that a cotti- pensation takes place between the digested portion of the crude fibre and the undigested portion of the nitrogen-free extract. That is to say, these two quantities are always nearly equal, so that the amount of the nitrogen-free ex- tract found by analysis is cm approxwnate measure of the di- gestiMUty of the total non-nitrogenous matters of the fodder, excZusi/oe qffat* {i.e., crude fibre + nitrogen-free extract). This fact, however, is only true in a general way and on the average. In particular cases considerable variations are not infrequent, so that the quantity of non-nitrogenous substance digested varies from sometimes 120 per cent, to as low as 80 per cent., or even less, of the amount of nitrogen-free extract found by analysis, the theoretical number being, of course, 100 per cent. It has been observed in several cases that the exactness of the compensation between the digested crude fibre and the undigested extract is influenced by the digestibility of the crude fibre. Thus Stohmann,t who was the first to call attention to this fact, obtained in experiments on goats, the following figures for meadow hay : Hay No. 1. Hay No. 2. Hay No. 3. Hay No. 3. (Another animal.) Digestible fibre and extract in per cent, of nitrogen-free extract. . . Digestibility of crude fibre 97 63.6 86 58.0 82 51,0 73 446 * The fat is sometimes included. Its amount is so small as to make little difference practically. t " Biologische Studien," 1 Heft, p. 72. MANUAL OF OATTLE-FEEDING. 251 Here it is evident that with increasing indigestibility of the crude fibre the amount of digestible non-nitrogenous matters falls more and more below the quantity of nitro- gen-free extract, while only in the first case are the two approximately equal. Other investigators have confirmed this result, and it has also been shown that the decrease in the digestibility of the total non-nitrogenous matter is, at least in some cases, less rapid than that in the digestibility of the crude fibre. The younger and more tender a fodder is, the smaller is generally its percentage of crude fibre, and the greater is the digestibility of the latter. As a consequence, the "whole amount of non-nitrogenous matters digested from such a fodder is generally larger, in comparison with the quantity of nitrogen-free extract, than is the case with one cut at a more advanced period of growth. As an example of this may be mentioned some experi- ments on sheep made by Wolff, at Hohenheim, in which the animals were fed with green clover cut at four differ- ent periods of growth, No. 1 being the youngest and Not, 4 the oldest. The first line (a.) of the table gives the per- centage obtained by dividing the quantity of non-nitroge- nous matter actually digested by the amount of nitrogen- free extract found by analysis, and hence shows how much tlie amount actually digested varied from the theoretical amount. The second line (b.) gives the percentage of the crude fibre which was digested. No. 1. No. 2. No. 3. No. 4. («.) (J.) 111.9 60.0 105.5 53.0 101.8 49.6 88.5 38.8 252 MANUAL OF CATTLE-FEEDING. la No. 1 and No, 2, whose crude fibre was easily digest- ible, the actual amount of non-nitrogenous nutrients di- gested was greater .than that calculated ; in No. 3 the two were nearly equal ; in No. 4, where the crude fibre was less digestible, it was only 88.5 per cent, of the theoretical amount. It is obvious, from such results as these, that while the compensation between digested crude fibre and undigested nitrogen-free extract may be an aid in forming an estimate of the digestibility of a fodder, it is not sufficiently close to serve as the basis of exact calculations. Kecent experiments on the horse, to which reference will be made in subsequent pages, have shown that crude fibre is less digestible by this animal than by ruminants, and that consequently this compensation oidy takes- place in very young and tender fodder. Composition of Digestible Portion of Nitrogen-free Extract. — It has been shown, by essentially the same method as that applied to crude fibre, that the digestible portion of the nitrogen-free extract has very nearly the composition of starch. We may therefore assume that all the digestible non-ni- trogenous substances of the fodder, with the exception of the fat, are, like starch itself, converted into sugar or sugar- like substances, and as such are resorbed and taken into the circulation. Further exceptions to this rule are the small quantities of organic acids either contained ready formed in the fod- der or produced during digestion from the carbhydrates. The quantity of these, however, is very small, and we can,* in general, regard all the digestible non-nitrogenous * With the reservations made on p. 184. MANUAL OF CATTLE-FEEDING. 253 matter of the fodder, except the fat, as composed of carb- hydrates and as having the same fmictions in nutrition as sugar and starch have been proved to have in the experi- ments which have been detailed in Part I. Composition of Undigested Nitrogen-firee Extract. — The part of the nitrogen-free extract which remains undigested is a mixtm-e of various substances richer in carbon than the carbhydrates and having, as a whole, nearly the percentage composition of lignin, as given on p. 39. It is therefore a matter of comparative indifference in fodder analyses, whether the lignin dissolves in the acid and alkaline liquids used to isolate the cellulose or remains with the latter as incrusting substance. In one case it ap- pears in the results of analyses as part of the nitrogen-free extract, in the other, as crude fibre ; in both cases it reap- pears in the excrements and leaves the total quantity and quality of the digested nutrients the same, and the only effect of a variation of this sort would be on the compen- sation between the undigested extract and the digested fibre. The Aqueous Extract. — From the numerous experi- ments executed in Weende on oxen and sheep, the law has been deduced that the total quantity of solid matter that can be extracted from a fodder by boiling water, *. e., the aqueous extract, is a measure of the digestible portion of the nitrogen-free extract. In single cases, however, con- siderable variations from the rule were observed on both sides of the average, amounting to as much as 14 per cent. This method of judging of the quality of coarse fodder has not found any general application, for the reason that no necessary connection exists between the digestible ni- 254 MANUAL OF CATTLE-FEEDING. trogen-£ree extract and the amount of substances soluble in water, since the latter includes not only non-nitrogenous matters but also larger or smaller quantities of protein and ash. The rule is to be considered as, at best, a purely empiri- cal one, which, to be sure, has some value for practical purposes, since in general the digestibility of a coarse or green fodder is greater the more solid matter can be ex- tracted from it by boiling water, but to which no scientific value can be attached. Crude Pat. — That the crude fat, or rather the ether extract, of the coarse fodders is a mixture of the most various substances, some of which are digestible and some indigestible, has been already explained. The chlorophyll, or green coloring matter of plants, is soliTble in ether, but seems to be entirely indigestible, and the wax-like sub- stances most probably belong to the same category. It is therefore to be expected that the digestibility of the crude fat will be very different according to the kind and quality of the fodder. It is always greater in yoimg and tender plants than in older ones, and it has also been ob- served that the crude fat of clover hay and of the straw of the legumes is generally more digestible than of that of meadow hay and the straw of the cereals. Crude Protein. — ^The digestibility of crude protein in the various kinds of coarse fodder is subject to greater variations than that of almost any other constituent. Of the protein in clover hay and meadow hay, e. g., a quantity varying, according to circumstances, from 35 per cent, to 76 per cent, of the total amount is digested. Generally the protein is more easily and completely digested the greater the percentage of it contained in the fodder, i. e., the narrower the nutritive ratio. At the same time, the MANUAL OF OATTLE-PEEDrrrO. 255 quantity and quality of the crude fibre has an influence on its digestibility. PormulaB for Digestibility of Protein. — ^As we have seen, the digestibility of the non-nitrogenous matters of a coarse fodder, with the exception of tli6 small quantity of fat which it contains, can be estimated from the results of analysis with sufficient accuracy for practical purposes, al- though not with scientific exactness. Unfortunately, we have no such simple means of esti-, mating the digestibility of the crude protein, although the attempt has more than once been made to supply one in the shape of a formula which should enable us to deter- mine the digestibility of tlie crude protein of a fodder or of a ration by calculations based on its composition. These formulae are, of course, all empirical, being founded on the results of as many feeding experiments as possible. In view of the importance of protein in nutrition, and the great variability which experiment has shown to exist in its digestibihty, the advantages to be derived from a correct formula of this sort are manifest. Nevertheless, none of the various formulae which have been proposed have met with much favor, and it seems to be the opinion of the best^uthorities that it is yet too soon to attempt their formation. All these formulae aim to express the influence of the chemical com/position of the fodder or ration on the diges- tibility of its protein — an influence which, though an im- portant one, is by no means the only factor involved. As regards coarse fodder alone, they offer little advantage over the intelligent use of " digestion coefficients," and the less since the results obtained by their aid sometimes vary widely from the truth. In the case of a ration including considerable concentrated fodder, they seem to yield more 256 MANUAIi OF CATTLE-FEEDING. exact results, and may prove of value to test tlie corre- spondence of a ration with the feeding standard, though they -would be of but little use in compounding it. For this purpose, Stohmann's formula * is probably the best. It is the following ; in which j)' represents the digestible protein, jp the total " crude protein," and s the total non-nitrogenous matters of the ration, including fat. This formula makes the digestibility of the protein de- pend on the relative amounts of nitrogenous and non- nitrogenous nutrients, ignoring the influence of the amount of crude fibre. For this reason, it appears to give better results when applied to rations containing much concen- trated fodder than when used for those composed exclu- sively of coarse fodder. Finally, it must never be forgotten that these formulae are entirely different from those of the mathematician. They do not, like those, express necessary truths, nor are they deduced from any well recognized natural law. They are inditciions, and depend for their value on the number and accuracy of the observations upon which they are based. They may be of much value, but we must beware of trusting them too implicitly. In regard to the digestibility of the protein of the coarse fodders, much that is of importance and can find application in practice has already been ascertained. On the more important kinds of coarse fodder large numbers of digestion experiments have been made, and we are able to give, as the results of these, coefficients expressing the • Landw. Versnohs-Stationen, XI., 401. MANUAL OF CATTLE-FEEDING. 257 average digestibility of the protein and the other ingre- dients of fodders as well as the range of^ variation ob- served. (See table in Appendix.) Some of these num- bers are the average of more than fifty experiments, and therefore may be regarded as expressing, with con- siderable accuracy, the average digestibility of these sub- stances. Others are the result of only a few trials, and hence are more liable to correction by the results of new experiments. Furthermore, we are able to judge, to some extent, of the digestibility of the protein in coarse fodder of different qualities and cut in various stages of growth, and of its digestibility by different kinds of animals, and have acquired some knowledge of the influence exerted upon it by the addition of concentrated feeding-stuffs to the ra- tion. These points wiU be considered in the following sections. Non-Protein. — Besides protein, coarse fodder, especially when cut young, is likely to contain a greater or less quantity of amides and other nitrogenous substances which we may, for convenience, designate as 7wn-jprotem. These, so far as investigated, are soluble substances, and there is little doubt that they are easily and completely di- gested. In all the statements of the previous paragraph reference was had to " crude protein," that is, to the total nitro- genous matters of the fodder. If account be taken of the amount of "non-protein" present, the digestibility of the true protein would, of course, be less ; but how much less future investigations must show. Ash. — Phosphoric Add. — When ruminants are fed exclusively on coarse fodder, only traces of phosphoric acid are found in their mine. Only so much of the phos- phoric acid of the fodder seems to be resorbed as is neces- 258 MANTTAL OF CATTLE-FEEDING. sary for whatever formation of new tissue or of milk may take place ; all the rest is excreted in the dung. On the other hand, the urine of the ruminants is, like that of the carnivora, very rich in phosphoric acid (20 to 45 per cent, of the ash) when the animals are fed exclusively on milk, or when full-grown animals are deprived of food for several days, so that they finally subsist upon their own flesh and fat. When calves and lambs are fed large quan- tities of grain, a greater or less quantity of phosphoric acid always appears in the urine. The method of excretion of the phosphoric acid of the fodder therefore varies with the kind of feeding. Accord- ing to Liebig, phosphoric acid is absent from the urine of herbivora because this liquid is usually alkaline and be- cause the fodder usually contains much lime. Phosphate of lime is insoluble in alkaline fluids, and therefore phos- phoric acid only appears in the urine when more is con- tained in the fodder than is sufficient to unite with the lime. Presence of magnesia, on the other hand, as Bert- ram * has recently shown, does not hinder the appearance of phosphoric acid in the urine, even though the latter be alkaline. When this takes place the urine is found to be free from lime. ' Other Ash Ingredients. — Of the alkalies of the fodder 96 to 9Y per cent., of the magnesia 20 to 30 per cent., of the lime only 2 to 5 per cent, and sometimes none, and of the sulphuric acid and chlorine, nearly the whole quantity, is excreted in the urine. The remainder of the above- named ash ingredients, so far as they are not held back and used in the body or in the production of milk, is foimd, along with the whole of the silica, in the dung. • Biedermanu's Geutial-Blatt, Jahrg. 8, p. 108. MANUAL OF OATTLE-FEEDING. 259 § 2. CntCmiBTAlICBB APFECTIKa THB DlOESTIBILITT OF COABSB Fodder. Influence of the Quantity of Fodder. — Feeding vary- ing quantities per day and head of the same coarse fodder does not alter tlie percentage digestibility of the various nutrients. E. g., i£ on a certain ration of hay an animal digests 76 per cent, of the total quantity of crude protein, and the amount of the ration be increased by one-third or one-fourth, 76 per cent, of the protein wUl stiU be digested, and the absolute quantity will accordingly be one-third or one-fourth greater. This fact is shown by a number of the Weende experi- ments in which varying quantities of meadow hay or clover hay were fed to oxen, and also in experiments by Wolff,* at Hohenheim, on sheep fed on dover-hay. In the latter experiments the following results were ob- tained : Fodder per day. FonndB. DiOKsmo). Protein. Per cent. Fat. Per cent. Crude fibre. Per cent. Nitrogen- free extract. Per cent. 3 59 61 60 65 56 54 51 64 51 63 2 64 2 63 Some later experiments by the same investigator f have shown that the same fact is true of the digestibility of lucerne hay by sheep and likewise by the horse. The re- sults on the latter animal were as follows-: * " Die Versuchs-Station Hobenheim," p. 75. f Landw. Versachs-Stationen, XXI., 20. 260 MANUAL OF CATTLE-FEEDING. Fodder per day. Founds. Protein. Per cent. Fat. Per cent. Crude fibre. Percent. Nitrogen- free extract. Per cent. 17.6 74 73 77 •• 33 37 43 70 22.0. 71 26.4. 72 A point to be considered is that all the observations hitherto made have been only on meadow haj, cloverj and lucerne, of good or medium quality ; but the same fact is, in all probability, true also for the more indigestible fodders, such as straw, chaff, etc. This constancy is very important, and facilitates greatly the calculation of rations for the various purposes of agri- cultural practice. Ijffect of Drying. — All the nutrients of dry coarse fod- der are digested and resorbed to the same extent as wh^n it is fed green. Of the numerous experiments on this point, the follow- ing, by Weiske,* may serve as an example. They were made on two sheep, with lucerne, which was first fed 'green, and then after having been carefully dried without loss. The averages of the results on both animals were : Digested. Protein. Per cent. Crude fibre. Per cent. Pat. Per cent. Nitrogen- free extract. Percent. Green 79 78 33 34 38 50 68 65 ^ " Dry • Wolff : " Die Bmahrung der Landw. Nutzthiere," p. 97. MAKTJAL OP OATTLE-rEEDING 261 With the exception of the fat, whose digestibility, as we have seen, cannot be determined very accurately, the seve- ral nutrients were equally well digested in the two cases. This result, which has been fully confirmed by many other experiments, stands in apparent contradiction to the general experience of farmers. It must be remembered, however, that it is only true when the green fodder and the hay are otherwise of exactly the same quality; when both are cut at the same time and from the same field, and when none of the leaves or other tender and especially nutritious parts are lost during the preparation of the hay. These conditions are never completely reached in prac- tice, especially in the making of clover or lucerne hay, and for this reason, and also because green fodder is commonly used at an earlier stage of growth than that which is con- verted into hay, a greater nutritive effect is generally ob- served with green fodder. For the present we may pass over the question whether the large quantity of water which milking animals con- sume in green fodder exercises any considerable influence on the amount of milk produced, but the digesMbiMty of the organic constituents of a fodder is in no way altered by simple drying in the air, provided it is executed with- out loss of parts of the plants. On the other hand, the ordinary method of making hay involves a considerable loss of leaves, etc., and the product suffers not only in its quality, as shown by chemical analy- sis, but in its digestibility as well. For example, in some experiments at Hohenheim, by Wolff, Funke, and KeUner,* the loss involved in the prep- * Landw. VerBUchs-Stationen, XXI. , 425. 262 MANUAL OF CATTLE-FEEDING. aration of lucerne hay amounted to 7.13 per cent, of the dry matter, and the composition and digestibility of the resulting product, as compared with that obtained by dry- ing the same material without loss, were as follows : Composition. DlOXBTIBnjTT. Dried withontloBS. Hay. Dried without lofls. Hay. Protein 17.00 31.81 43.80 7.39 14.94 33.90 44.22 6.94 100.00 71 48 66 29 67 Crude fibre 45 Nitrogen-free extract | Fat :....) 62 JlBh 23 100.00 Ijfiect of Storing. — The storing of fodder for a long time, even when aU necessary precautions, such as a dry and airy location, etc., are observed, may decrease both its digestibility and palatability. At least, this conclusion can be drawn from some experi- ments executed in Hohenheim.* Of the crude protein of a sample of rowen, 62 per cent, was found digestible directly after the harvest, while three months later 56 per cent., and in the following spring 54 per cent., of the total quantity was digested by the same animals. The digesti- bility of the crude fibre also decreased somewhat, while that of the other nutrients remained about the same. A similar fact was observed by Hofmeisterf in regard to clover hay, and essentially the same results were also ob- tained in later experiments in Hohenheim. ♦Landw. Jahrbucher, II., 382. f Landw. Yersuchs-Stationen, XVL, 353. MANUAL OF CATTLE-FEEDING. 263 In all the Hohenheim experiments, the chemical compo- sition of the foddei" remained substantially unchanged, and the deterioration showed itself in a diminished digesti- bility. Whether, however, the smaller nutritive value of hay and straw kept over winter, which is often observed in practice, even when the hay has apparently kept excellent- ly, is caused by an essential alteration in the digestibility of the fodder, or isto be sought chiefly in the mechaiiical loss of the more nutritious parts, which always takes, place to some extent, and in decreased palatabUity, must be left to future researches to decide. Period of Gro-wth. — ^Early cut forage is not only supe- rior, other things being equal, to late cut, as regards its chemical composition, but it excells it in digestibility as well, This fact is established by abundance of experimental evidence. In some experiments by G. Kiihn,* oxen were fed with clover hay cut from the same field at three different times, viz. : I. Out May 20, just before flowering. II. " June 7, in full bloom, in. " " 20, end of flowering. The composition and digestibility of the water-free sub- stance of these hays were the following : Composition. Protein. Per cent. Crude fibre. Per cent. Fat. Per cent. Nitrogen- free extract. Per cent. Ash. Ver cent. I 19.56 16,31 13.19 35.30 38.11 38.80 3.25 . 2.87 3.86 45.53 44.95 48.37 10.10 II 7 76 m 6.78 • WolfE : " Emahrung Landw. Nutzthiere," p. 106. 264 MANtTAL OF CATTLE-FEEDING. DlGKBTIBILITT. Protein. Percent, Crude fibre. Per cent. Fat. Percent. Nitrogen- free extract. Per sent Ash. Percent. I 76 65 59 51 47 40 68 64 60 70 68 66 n Ill In experiments made at Hohenheim on clover cut at four stages of growth and fed to sheep, a similar decrease of the digestibility with increasing age was observed, that of the protein falling from 75 to 59, and that of the crude- fibre from 60 to 39. Many other similar experiments might be cited. Another circumstance which increases the feeding value of early cut forage is the fact that it is not only more digestible, but contains a much larger percentage of crude protein than is found in that cut later. The difference in the actual quantity of protein digested is thus larger in a two-fold ratio in early cut fodder. Thus, in the above- mentioned experiments by G. Kiihn, the quantity of pro- tein actually digested amounted, in the first case (I.), to 13.9 per cent, of the total dry matter of the fodder ; in the last case (III.) to only 7.8 per cent. These facts make it evident that the same kind of coarse fodder may differ greatly in its nutritive effect, according to the circumstances under which it is grown and har- vested. In considering these results, however, it is to be remem- bered that, as regards protein, the coefficients express the digestibflily of the total nitrogenous matters, both albumi- MANUAL OF OATTLE-PEEDINO. 265 noids and non-albuminoids. As we have seen, recent in- vestigations have revealed the presence of large amounts of " non-protein " in coarse fodder, especially in the earlier stages of its growth. This non-protein is, in all proba- bility, entirely digestible, and it is easily to be seen that its presence might affect the correctness of the above re- sults. The only experiments touching this point are a few by Wolff * on sheep and on a horse, with hay cut from the same field in two different years. These gave the fol- lowing digestion coefficients, a for total nitrogenous matter, J for true protein : Fodder cat. Sheep. HOBSE. a. ». u. ». April 24, 1874 Maris, " 79.1 71.1 69.1 73.3 72.1 55.5 73.3 64.3 64.2 59.1 66.7 51.9 68.8 66.1 61.8 .... June 10, " May 14, 1877 53 1 June 9, " 59 6 " 26, " 58.7 These figures are somewhat conflicting as regards the digestibility of the true protein in fodder cut at different times, and it must be left for future investigations to de- cide how far the results which have been obtained for the total nitrogenous matter of coarse fodders are true of their actual protein. Methods of Preparing. — While the various methods *Landw. Jahrbiielier, VIL, I. Supplement, p. 263. 12 266 MANUAL OP CATTLE-FEEDINO. of preparing fodder for animals, such as steamiiig, ensi- lage, etc., may be accompanied by practical advantages, all the -experiments hitherto executed show that the diges- tibility is not sensibly increased thereby. Thus, in the experiments executed in 1862, at the Dahme Experiment Station, by HeUriegel & Lucanus,* it was found that the digestibility of rye-straw by sheep was not increased either by fermenting or cooking it. Experiments in Proskau, by Funke, gave the same re- sults regarding the digestibility of the total dry matter and the cellulose of a mixed ration fed to milk cows. Indeed, recent experiments at Poppelsdorf f showed a decreased digestibility of hay as a result of steaming. A rather coarse hay was fed to oxen, first dry, then steamed, and finally moistened with as much water as it took up when steamed. The following were the results : DlOESTIBnjTI. ; Total Orgnnic matter. Per cent. Protein. Per cent. Fat. Per cent. Crude fibre. Per cent. Kitrogen- frce extract. Per cent Dry steamed Moistened. 58 56 54 46 30 39 39 41 38 59 - 58 54 60 59 67 Steaming and moistening seem to have affected the di- gestibility of the protein especially. It is possible that the large decrease observed may have been caused by an ex- traction of soluble nitrogenous matters, though care seems * Landw. Versuchs-Stationen, VIL, 243, 324, 387, and 467. \ Eombergei : Landvic Jabibucbei, VIII., 933. . . MANUAL OF CATTLE-FEBDINa. 2|87 to have been taken to avoid tliis, but no increase of digest- ibility as a result of cooking is shown. In these experiments the steamed fodder was purposely allowed to cool before it was used, in order to observe only the effect of cooking, and no preference for the steamed , fodder on the part of the cattle was observed, but r^/ther the reverse. In practice, however, the palatabUity of a fodder may often be very considerably increased by suita- ; ble preparation, and the animals thus induced to eat larger, quantities of a fodder not perhaps agriBeable to them in its natural state. It would seem that some gain must also accrue from warm fodder (see p. 239). The preparation of fodder may thus produce very favorable results in a prac- tical point of view, although the quantity of nutrients which an animal extracts from a given amount of dry substance is no greater in one case than the other. As in the case of coarse fodder, the digestibility of con- centrated fodders is not increased by the method of prep- aration. This is shown, e. g., by experiments made in Mockem on feeding bran to oxen ; not only was the diges- tibility not increased, but, on the contrary, decreased more or less by boiling, addition of leaven and production of in- cipient fermentation, and stiU more by successive treatment with alkalies and acids. The effect was greatest on the protein and least on the non-nitrogenous constituents. Digestibility by Diffferent Kinds of Animals. — The different kinds of ruminating animals, as oxen, cows, sheep, and goats, digest tlie same fodder equally well. As a mean of about forty single determinations, the di- gestibility of all the constituents of meadow hay is found to be about 2 per cent, greater in the case of oxen and cows than in that of sheep, while, in a still greater num- ber of experiments, clover-hay or green clover is found 268 MANUAL OF OATTLE-FEEDIITO. to be digested 2 to 3 per cent, better by steep than by oxen and cows. The differences, small in themselves, thus fully compensate each other in the two kinds of hay. In feeding-experiments on goats, likewise, average diges- tion coefficients have been observed in all experiments yet made. In the case of a non-ruminating animal, like the horse, coarse fodder is less completely digested than by rumi- nants. A large number of experiments on the comparative di- gestibility of various feeding-stuffs by the horse and sheep have lately been executed at the Hohenheim Experiment Station, under Wolffs direction. A comparison of all the results yet obtained * leads to the following conclusions : 1. Meadow-hay is less fully digested by the horse than by sheep, the difference amounting to 11 to 12 per cent, of the water-free substance. 2. The crude protein of hay is nearly as digestible by the horse as by sheep. In the better qualities of hay ex- perimented upon, the difference amounted to 4 to 6 per cent, of the total amount, while in some of the poorer sorts more was digested by the horse than by sheep. This appears to be the case not only with the total nitrogenous matters but also with the true protein (compare p. 265). 3. Of the non-nitrogenous constituents of hay, the nitro- gen-free extract is slightly, and the crude fibre considera- bly better digested by sheep than by the horse. As a result, the nutritive ratio of the portion of the hay di- gested is narrower in the case of the horse than in that of sheep. As regards fat, all the experiments gavo very low results for this nutrient, owing to the presence of a con- * Iiandw. Jahibiicher, YIIL, L Supplement, p. 97. MANUAL OF CATTLE-FEEDING. 269 siderable quantity of biliary products, etc., in the excre- ments. 4. Of two kinds of lucerne hay, the protein and nitro- gen-free extract were equally well digested by the horse and by sheep, while the crude fibre appeared to be rela- tively somewhat better digested than that of meadow hay. 6. The digestibility of straw (of winter wheat) was found to depend somewhat on the amount of mastication it received, but in general to be small. Under ordinary cir- cumstances it seems to be hardly half as well digested by the horse as by ruminants. 6. Concentrated feeding-stufEs (oats, beans, and maize, the two latter soaked with water) are digested to the same extent by the horse and by sheep. Similar observa- tions have been made regarding the digestibility of con- centrated fodders by the hog. All these conclusions apply, in the first place, only to the conditions of these experiments, but, at the same time, there is every reason to expect that they will be confirmed _by subsequent investigation, at least in their main features. Influence of Breed. — If the various species of rumi- nants digest their fodder to the same extent, we should still less expect to find important differences in this respect between the breeds of one and the same species. In fact, repeated experiments in Dresden and Hohenheim have agreed in showing that, e. g., Merinos, Southdowns, and the so-called Wurtemberg Bastard-sheep, both when store-fed and on an exclusive ration of meadow or clover- , hay, as well as on a more or less rich fattening fodder, digest the same feeding-stuffs about equally well. In these considerations we must not confuse the digest/I- iUiiy of a fodder with its nutritvoe effect. The latter may be very unequal in the different breeds, and is determined, 270 MATTTJAL OF CATTLE-FEEDINO. on the one hand, by the appetite of the animal and the quantity of fodder which it can eat and digest day by day, and on the Other hand, by the whole organization of the animal and its temperament and congenital peculiarities. With this, however, the actual percentage digestibility of a fodder has primarily nothing to do. The latter is essentially the same in all breeds for the same fodder, it being, of course, assumed that there are no individual peculiarities of digestion to disturb the result. Age of the Aniinals. — Even at different ages or in different stages of growth the digestive power for any given fodder seems to be nearly the same, provided that the animals are weaned from milk and that the fodder is agreeable in taste and sufficient m nutritive effect. This fact has been shown by experiments made in Hohenheim * on lambs of two races, and continued for nine months con- secutively (from the fifth to the fourteenth month of their age), and which included both exclusive hay fodder and rich feeding with hay and grain. Recent experiments made by Weiske f on lambs, extending over about ten jnonths, have given the same result. It is of course possible that this constancy of digestive power would be less marked in case of a poor and diffi- cultly-digestible fodder, but young animals, so long as they are capable of and incUned to rapid growth, cannot thrive on such a fodder ; they consume a quantity insufficient for their normal nourishment, and must suffer under a long continuance of such treatment. Individual Peculiarities have often a greater influence on the digestive process than the breed or even the species of the animal. • Landw. Jahrbuoher, II. , 219. flbid., IX, 205. MAWTJAI, OP OATTLE-FEEDING. 271 Besides temporary disturbances of digestion and the weak digestion caused by old age, animals of the same species and breed and of the same age and live-weight often show constant differences in digestive power, which, however, seldom exceed 2 to 4 per cent, of the total dry matter of the fodder. Greater differences in digestive power sometimes show themselves in single individuals which fall strikingly below other animals of the same age in development and live- weight. For example, a difference of 1 per cent, in the digestibility of the total organic matter, and of 15 per cent, in that of the crude fibre, was observed in such a case in Proskau. At the same time, however, it was found that those animals of a herd which . attained the greatest live-weight in a certain time on a given kind of fodder did not always possess the greatest digestive power nor produce the most live-weight from the same weight of food. The greater or less appetite, and the quantity of fodder daily eaten, are much more important conditions of the increase in weight of growing or fattening animals than an increased digestive power. Actually stunted animals, those which have been insuffi- ciently nourished in youth, especially during suckling, have also generally a relatively weak digestive power in later sta- ges of development. How far the latter can be strengthened by the manner of rearing still remains to be investigated. Efffeot of Work on Digestion. — ^A question of some importance is the effect of the performance of work on the digestibility of the fodder. In the recent experiments at Hohenheim on the horse, already alluded to, this question was made the subject of investigation.* * Landw. Jahrbucher, YIILj I. Supplement, p. 73. 272 MANUAL OP OATTLE-FEEDINGi Two series of experiments were made. In the first, the daily ration consisted of 13.2 lbs. of oats, 11 lbs. of hay, and 3.3 lbs. of cut straw; in the second, of 16.5 lbs. of hay and 8.8 lbs. of beans. In the following tables are to be found the amount of work performed per day in each experiment, and the percentage digestibility of the several nutrients, reckoned on the total ration. Series L Work performed per day. Kllogramme-meterB, DZGEBTIBIIJTY. Total Organic substance. Per cent. Protein. Per cent Fat. Per cent. Crude fibre. Per cent. Nitrogen- free extract. Per cent. 475,000 950,000 1,425,000 950,000 475,000 600,000 1,800,000 600,000 58.73 58.63 58.66 56.41 54.83 70.84 67.63 69.95 66.63 68.31 53.05 53.55 45.90 48.73 45.99 31.24 39.03 33.33 25.83 36.95 68 27 69.61 68.37 67.65 64.41 Sekies U. 60.04 77.46 24.00 38.55 58.48 75.00 12.61 34.73 57.69 74.60 10.12 34.50 66.80 67.30 66.05 In each series the digestibility decreases slightly toward the close, but this is obviously independent of the amount of work performed. It was probably caused by a deterioration in the quality of the hay consequent on keep- ing and handling. In these experiments, then, the digestibility of the fod- der was not affected by the amount of work performed. MANUAL OF OATTLE-PEEDING. 273 Presumably, this is true in all cases, but these are the only experiments yet made on this point. § 3. Digestibility of Concentuated Foddbbs and teeib Influ- ence ON THAT OP COAKSB FODDEK. Method of Experiment. — The foregoing section shows clearly that the percentage digestibility of coarse fodder, so long as the latter forms the exclusive ration, is de- termined very largely by the chemical composition of its dry matter as affected by the time of cutting, weather, soil, manure, etc., while other circumstances, such as quan- tity, state of dryness, and method of preparation, as well as the kind, breed, and age of the animals, have very little influence upon it. This is an important result, and one of practical worth in the calculation of the daily ration of an animal. It is, however, still more important to investigate whether and how much the digestibility of the constituents of coarse fodder is altei-ed by the addition of concentrated fodders, as well as to determine the digestibility of the latter. In the nature of the case it is practically impossible to make direct experiments with concentrated fodders, since they are not suited for the requirements of herbivorous animals. The best we can do is to feed increasing quan- tities of any concentrates fodder along with a fixed quan- tity of coarse fodder of known digestibility, and ascertain the digestibility of the mixture as a whole. It is, of course, in most cases impossible to determine with certainty what portion of the digested nutrients comes from the coarse fodder and what from the concentrated fodder ; but results may be reached which possess sufficient exactitude for the purpose of compounding rations. 12* 274 MANUAL OF OATTtE'FEEDINO; If a concentrated fodder decreases the digestibility of the coarse fodder with which it is fed, we should expect, that with a greater relative quantity of the former in the ration the decrease in the digestibility of the ration as a whole would be also greater. We therefore proceed as follows : in a first period we determine the digestibility of the coarse fodder — hay, for example — ^when fed alone. In a second period we add to the hay a certain amount of the concentrated fodder in question — maize meal, for instance — and determine the digestibility of the mixture. In a third period we increase the relative quantity of meal very considerably, and deter- mine the digestibility of this mixture. Now, assuming the digestibility of the hay to have been the same in the second and third periods as in the first, we calculate, from our experimental results, the digestion co- efficients for the maize meal in the second and third periods. It is obvious that, if neither feeding-stuff has altered the digestibility of the other, these two sets of digestion co- efficients ought to be the same within the limits of experi- mental error, and, in that case, we have not only proved this fact but have also determined the digestibility of the maize meal. On the other hand, if the digestibility of either feeding- stuff has been diminished by the presence of the other, it is plain that our method of calculating the results will show an apparent decrease in the digestibility of the maize meal. In the case supposed it would be impossible to determine directly in which of the two feeding-stuffs the decrease took place, and the method of expressing the results would depend partly on the results of other experi- ments and partly on questions of convenience. MANUAL OF CAMLE-FEEDING; 275 Some of the examples contained in the following para- graphs will, perhaps, make the method of calculation clearer, while they at the same time serve to elucidate some of the practical questions that arise. These questions concern chiefly the influence of concen- trated fodders on the digestibility of coarse fodder, and to them we shall devote most of our attention, since it is im- possible, within the limits of this work, to notice the numerous experiments on the digestibility of the various concentrated fodders. For the results of the latter the reader is referred to the Appendix. Effect of Albuminoids. — E. Schulze & Marcker,*^ in Weende, have made experiments on the effect of a prepara- tion of wheat-gluten containing 78 per cent, of albuminoids on the digestibility of meadow-hay. They experimented on sheep, and obtained the following results for the per- centage digestibility of the hay, on the assumption that the gluten was whoUy digested : Protein. Crude Fibre. Fat and nitrogen- free extract. Total organic matter. 67 53 -4 57 58 + 1 66 67, + 1 63 ' Hay and 119.4 grms. gluten.. Difference 63 + 1 A second experiment, with a larger amount of gluten, gave, on the same assumption, the:following resplts : Protein. Crude Fibre. Fat and iii- tragen-free extract. Cfrganio matter. Hay alone 65 49 -6 55 61 +6 65 61 -4 61 Hay and 363.2 grms. gluten. Difference 60 -1 * Jour, ftir Landwirthachaft, 1871, p. 68. 276 MANUAL OF CATTLE-FEEDINQ. The slight decrease iu the digestibility of the protein of the hay becomes so exceedingly small, when calculated on the whole ration, as to be of no practical significance, while the gluten exerted practically no influence on that of the remaining nutrients. Thus, these results show not only that even these large additions of albuminoids to the fodder produced no essential alteration of digestibility, but also that the gluten was almost completely digestible. Very similar results were obtained in a series of experi- ments, executed at Hohenlieim,* on the digestibility of " flesh meal " by swine. It was fed in varying quanti- ties along with potatoes. Assuming that the digestibility of the potatoes was not altered by the addition of the highly nitrogenous flesh meal, the following numbers were obtained for the digestibility of the latter : Number ot animal. Fed. DlGESTIBIUITY OF FlESH-MiaI,. Period. Potatoes. Gnus. Plesh meal. Grma. Protein. Per cent. Fat Per cent. Organic substance. Per cent. I I II IL II II m Ill 2 3 1 4 2 3 1 4 4,500 5,000 5,000 4,500 6,500 8,000 7,500 7,500 6,063 190 210 500 450 195 240 225 225 279 95.1 97.0 98.5 98.9 102.9 96.4 91.4 98.6 97.4 82.3 87.5 88.7 88.5 75.2 90.7 83.3 89.6 85.7 93.4 96.1 93.5 90.9 94.3 86.9 87.8 90.4 Average 91.7 • Landw. Jahrbiicher, VIIL, I. Supplement, p. 200. MANUAI, OF CATTLE-PEEDnrO-. 277 Though the ratio between potatoes and flesh meal varied between wide limits, the digestibility of the latter, calcu- lated on the basis of unaltered digestibility of the former, varied but very little, and rather increased than decreased in the experiments in which relatively most flesh meal was fed. Since the flesh meal contained no crude fibre or ni- trogen-free extract, the digestibility of these ingredients of the potatoes could be determined directly in each ex- periment. It was found to b«^^ sensibly the same in aU. Obviously, the results of these experiments are as ifihe potatoes were equally well digested in all cases, and as if the above coefficients representtid the digestibility of the flesh meal ; and though this facb cannot, perhaps, be said to be absolutely proved, the practical result is the same as if it were, and we can make it the basis of calculations of digestibility in similar cases. Nitrogenous Bye-Podders. — By means of experiments made on the same plan as those just described, it has been found that for the ordinary nitrogenous bye-fodders, such as oil cake, cotton-seed cake, bvan, beans, etc., digestion coefficients may be obtained, and that these coefficients remain nearly constant whatever the quantity of the fodder given, while the digestibility of the coarse fodder remains unaltered by the addition of the concentrated fodder. This conclusion is drawn from the results of numerous digestion experiments in which increasing quantities of the concentrated fodder were fed along with meadow or clover hay. Such experiments have been made in Hohenheim, Mockern, and Halle, especially with oil cake, buj also with crushed beans, rape cake, wheat bran, and cotton-seed meal, on sheep, goats, and oxen, with the results stated. In all probability, experiment would show that the same 278 MANUAL OF OATTL^E-FEEDING^ tiling is true of other highly nitrogenous bye-fodders, e. g., all kinds of oil cake, the legumes, brewers' grains, etc. The results of these determinations of the digestibility of bye-fodders are included in Table II. of the Appendix. As the general result of the experiments, we can say that nitrogenous hye-fodders do not decrease the digestibility of the coarse fodder with which t/iey are used. The Gr£uns. — The influence of the grains, i. e., of con- centrated fodders with a medium nutritive ratio (1 : 5-8), on the digestibility of coarse fodders has received compar- atively little attention. Oats have been the subject of experiments by Hof- meister & Haubner * and by Wolff f on sheep. In both investigations it was found that an addition of oats to the coarse fodder did not essentially alter its digestibility. Wolff obtained the following results, on the assumption that the digestibility of the coarse fodder (hay) was not altered : Crude protein of oats digested. Batio of hay to oats. Percen 1 : 1.76 78.0 1 : 3.09 78.4 1 : 3.30 78.5 The constancy of the digestion coefficient for oats shows, as explained above, that the assumption of unaltered diges- tibility of the coarse fodder is probably correct, and can at least serve as a basis for the calculation of rations. Hof- meister & Haubner's results were, on the same assumption, as follows : Batio of hay to oata. Grade protein of oata digested. Per cent. 1 : 0.18 74.0 1:0.44 74.1 1 : 0.75 67.3 * Landw. Versnohs-Stationen, VI., 185 and 301. fLandvr. Jahibiichez, II., 288. MANUAL OF CATTLE-FEEDING. 279 Here we have also a nearly constant coefficient for the protein of the oats, except in the last case, where a slight depression is observed, which may indicate an actual de- crease in the digestibility of the hay. The oats used in WoMPs experiments had a considerably narrower nutritive ratio (1 : 5.16) than those used byHofmeister & Haubner, (1 : 7.07), and it is quite possible that the slightly smaller digestibility in the latter case, as well as its decrease in the third experiment, is due to this cause. The digestion coefficients of the other constituents of the oats, except those of crad& fibre, whose digestibility generally shows considerable variations in all the grains, were nearly accordant in all the experiments. The recent comparative experiments on the horse and sheep, made at Hohenheim, and to which reference has more than once been made, included determinations of the digestibility of oats, maize, and beans, when fed with coarse fodder. In no case was any noticeable infli^ence of these feeding-stuffs on the digestibility of the coarse fod- der observed. Experiments in "Weende by E. Schulze & Marcker* seem to indicate that when the nutritive ratio of the graiu or of the whole ration is wide (1 : 8-10), the digestibility of the coarse fodder may be diminished. We shall pres- ently see that feeding-stuffs rich in carbhydrates, especially roots, decrease the digestibility of coarse fodder. Grain with a nutritive ratio of 1 : 10, like that used in Weende, begins to approach roots in composition, and may produce a similar effect ; but we may safely say that grain of good quality (nutritive ratio 1 : 5-6) produces no decrease in the digestibility of coarse fodder. - * Jour. f. Landwiithschaft, 1876, 163. 280 MANUAL OP CATTLE-FEEDING. Effect of Caebhtdeates. — ^All investigation goes to show that increasing the protein of a ration has no ten- dency to diminish the digestibility of the latter, but rather to increase it. The carbhydrates, on the contrary, when added in large quantities to a ration, depress the digestibility of the crude iibre, and especially of the protein, to a considerable ex- tent. This has been observed in numerous experiments on oxen, cows, sheep, and goats, both when pure carbhydrates were fed and when fodders containing large amounts of these substances were used. Starch. — In the earlier Weende experiments this effect of starch on the digestibility of coarse fodder was observed, and the observation has been fully contirmed in later in- vestigations. Experiments of this sort have the advantage over many digestion experiments that it is possible to ascertain whether or not the starch is entirely digested. This sub- stance is free from protein, and hence any decrease in the digestibility of the latter must fall exclusively on the rest of the fodder. The same is true of the crude fibre and fat, while as regards the nitrogen-free extract, it is easy to determine, by a microscopic examination of the excrements, whether any of the starch has escaped digestion. The re- sults, therefore, possess no ambiguity. The following table contains a summary of the results of experiments by Henneberg & Stohmann, E. Schulze & Marcker, Stohmann, and Wolff, compiled from "Wolff.* The first column contains the name of the experimenter ; the second, the amount of starch fed, expressed in per cent, of the dry matter of the remaining fodder ; the third * "Bmahnmg Landir. Nutzthiere,'^ pp. 189-145. MANUAL OF CAXTLE'FEEDINa. 281 shows the character of the other fodder ; the fourth and fifth express the decrease in the digestibility of the protein and crude fibre in per cent, of the quantity of each which was digested when the starch was withheld. Deobeasi IK Di- No. Anthorltr. Starch to per cent. o£ other fodder. I'odder, exclusive ot Btaroh. gestibility OF Protein. Per cent. Crude fibre. Per cent. I..'.. 8.... 8.... Henneberg & Stotamaiin. II i< II II II 11 16 18 29 Clover-hay, ■ straw, and - beans. 7 11 21 6 7 16 4.... 5.... II II II II CI II 9 9 1 Same with J I more beans. | 3 i 4 a 6.... Schnlze & Marcker. 25 Hay. 41 10 7.... II II II 26 Hay and beans. 20 13 8.... Stohmann. 16 Hay. 12 12 9.... " 69 II 44 7 10.... " 16 Hay and oil-cake. 9 10 u.... Wolfl(ezpeiimentson hogs). 16 Barley. 12.... II 11 II 81 It 11 •• Two things are shown by this table : first, the greater the amount of starch which is added to a ration, the more is the digestibility of the protein and crude fibre decreased, e. g., in experiments 1, 2 and 3, or 8 and 9 ; second, the richer the original ration is in protein, the less is the de- pression caused by a given quantity of starch, e. g.. Experi- ments 6 and T. But this amounts to saying that the protein and crude fibre of a ration are better digested the narrower the nutritive ratio of the latter, a fact which, it wiU be remem- -bered, we have already noticed in the case of hay, and 282 MAKUAL OF CATTLE-FEEDING. which Stohmaim has made the basis of his formula (|). 256) for calculating the digestibility of the protein of a ration from its chemical composition. A large number of results seem to indicate strongly that this is a general law, of which the experiments cited above are only special cases, and that the non-nitrogenous matters of hay, e. g., as truly depress the digestibility of its protein and fibre as does the addition of starch. The only difference is that we can- not abstract the non-nitrogenous matters from the hay and observe the digestibility of the other constituents, but must determine the digestibility of the hay as a whole. The statement that starch decreases the digestibility of other fodder, then, is simply a practically convenient way of stating the result in this particular case. Sugar. — ISot many experiments on the influence of sugar on the digestibility of rations have been made 5 but those which have been executed show, as was to be ex- pected, that widening the nutritive ratio of a ration by means of sugar produces essentially the same result as when effected by starch. The decrease in the digestibility appears to be rather smaller, however. Effect on Digestibility of Nitrogen-free Extract. — Thus far we have considered chiefly the effect of easily digestible carbhydrates on the digestibility of pro- tein and fibre. In regard to the nitrogen-free extract and the fat of the coarse fodder, it may be said that the diges- tibility of these constituents is not essentially decreased by starch or sugar so long tail nu- fy^ti/ve matters, prot&m, and nutritwe ratio of the above ration (calculated on 1,000 pounds live-weight) with the 438 MANUAL OP CATTLE-FEEDING. corresponding quantities in the food of various other ani- mals:* Total nutritive matter. LbB. Digestible protein. Lbs. Nutritive ratio. Oxen at rest Sheep " Fattening oxen " sheep ^OS \t Calf 8.85 13.15 18.50 18.50 8.73 15.70 19.30 0.7 1.5 3.0 3.5 3.0 5.1 4.9 13 8.0 5.5 4.5 4.5 5.0 4.0 Both the total quantity of nutritive matter consumed by the calf and the amount of protein will be seen to be relatively greater than iu the case of any of the other herbi- vorous animals, while the nutritive ratio is narrower. The food of the young calf approaches more nearly in its composition that of well-fed carnivorous animals, as represented by ration b for the dog ; and the resemblance becomes still more close when we consider the compara- tively large amount of fat in the food of the calf. The greater rdalme consumption of food by young ani- mals, as compared with mature ones, is also strikingly shown in the experiments on lambs described ia § 3 of this chapter. * The rations for oxen and sheep are Wolff's feeding-standards. Of the two rations for the dog, a consists of 500 grms. fresh meat and 200 grms. fat — quantities which Voit found safficient to keep an animal weighing about 70 lbs. in fair condition — and 6 is a richer ration, con- sisting of 800 grms. fresh meat and 350 grms. fat. MANUAL OP OATTLE-FEEDING. 439 Produotion of Flesh. — We have already learned that the proportion of the albuminoids of the food which is converted into flesh is quite small in full-grown animals, while by far the larger proportion of the protein is de- composed in the body and excseted in the urine. In the young calf, on the contrary, more protein is retained in the body than is oxidized and excreted, the result being a rapid gain of flesh. The following table shows the rela- tion between consumption and gain of protein per day for an average animal weighing 100 lbs. : Eaten Ponuds. . Excreted in dung " Digested. " ( " Excreted in urine J I ^ I Pounds.. Betained in body i Nitrogen. Equivalent to protein. .078 .488 .004 .035 .074 .463 .030 .135 27 37 .054 .338 73 73 Notwithstanding thie large amount of protein eaten and the narrow nutritive ratio, both of which circumstances tend to increase the protein consumption in the body, the young calf excretes a comparatively small quantity of nitrogen in the urine. While it eats nearly as much protein as a well-fed dog of equal weight, it excretes about as much as the latter animal does in hunger. In other words, the sucking animal (in case of the calf at least) is able to apply a far larger proportion of the al- buminoids which it receives in its food to the building up 440 MANtJAL OP CATTLE-FEEDING. of its body than is the case with mature animals. Com- bining this with the relatively larger amount of food eaten, we can readily understand the rapid increase in weight of young animals. Production of Fat. — By means of a respiration appa- ratus, the excretion of carbonic acid in these experiments was determined. The following table gives the resxdt per day for the average animal of 100 lbs. weight, and also a comparison with the amount excreted per 100 lbs. body- weight by other animals : Calf 1.95 lbs. Man 1.3—1.4 " Dog (in hunger) 1.1 " " (wellfed) 1.8 " Ox (maintenance fodder) 1.0 " Ox (fattening) 1.3 " Sheep (maintenance fodder) 1.7 " The excretion of carbonic acid is, in general, relatively greater in the calf than in mature herbivora, and ap- proaches that of the well-fed camivora. The gain of carbon and consequently of fat per day was also considerable. Carbon per 100 ^.bs. livb-weight. In food 0.98 lbs. Excreted 0.53 " Gain 0.45 " Contained in the protein gained 0.18 " Gained as fat 0.27 " Corresponding to fat 0.35 " Fat in the food 0.47 " The amount of fat in the food was sufficient to supply all that was gained. MANUAL OP OATTLE-FEEDING. 441 Inorganic Nutrients. — In one experiment the con- sumption and excretion of the mineral ingredients were determined. The results on an animal weighing 151.2 lbs, were the following : Consumed. Grms. Excreted in urine and dung. Grms. Bet^inbd. Grms. Percent. Total ash 81.34 25.34 8.85 19.13 1.80 20.70 5.57 0.15 ^ 37.20 6.53 8.30 0.38 - 1.08 15.58 4.16 0.10 44.14 18.81 0.55 18.75 ■ 0.73 4.49 1.41 0.05 64.30 Phosphoric acid. ..... Chlorine. 74.23 6.22 Lime 1 98.00 Magnesia^ 40.00 Potash 22.37 Soda 25.31 Iron 33.33 The large amounts of lime and phosphoric acid retained in the body are specially noteworthy. These substances are the chief inorganic ingredients of bone, and their almost entire retention, particularly that of the lime, in the above experiment, indicates the importance of an abundant sup- ply of these ingredients in the food of growing animals. Soxhlet remarks that it would seem that the milk of our cattle is so poor in lime that it contains barely enough to supply the wants of the young animal, and that it may be advisable to help out the supply by the addition of chalk (carbonate of lime). This would answer the pur- pose of supplying material for bone-building as'well as the more costly phosphate of lime, since, according to the above results, a lack of phosphoric acid is not to be feared. 19* 443 MANUAL OF CATTLE-FEEDHTG. t 1% CAIiYES. In the foregoing pages we have endeavored to deduce, from experiments on calves, some principles vrhich may serve as the groundwork for practical conclusions. The data for this are, indeed, scanty, and the whole subject of the feeding of young animals needs accurate scientific in- vestigation. At the same time, we know enough to enable us to deduce some useful hints and indications. Before -weaning, milk usually forms the chief or only fodder. For the first few days after birth it is espe- cially important that the calf have the milk of its own mother. The so-called colostmm (p. 416) has an essentially different composition from the milk produced later, con- taining far more dry matter and considerable albumin, while the amounts of fat and sugar are relatively less ; the nutritive ratio is narrower, and the digestibility apparently greater. These differences nearly disappear in the course of a week (sooner in cows yielding much milk than in those yielding little), and after this it is a matter of indifference, so far as the nutritive effect is concerned, whether the calf be fed from its own mother or not. Nutritive Ratio. — That a milk diet is capable of supply- ing material for rapid growth is matter of common expe- rience, and is illustrated by the experiments of the preced- ing section. The comparatively narrow nutritive ratio of good milk does not cause that waste of protein which it would in mature animals, and the calf is thus enabled to consume relatively large quantities of this most important of all nutrients in a small bulk, and thus to supply the body with .abundance of material for growth. It would seem from some experiments, however, that MANnAL OF OATTLE-FEEDING. 443 the nutritive ratio may in some cases be advantageously made wider, especially if the milk is very rich. In some experiments made long ago in Saxony,* three calves, four- teen days old, and weighing 117, 130, and 114 lbs., were fed daily as follows : No. 1 with 13.2 lbs. cow's milk and 13.2 lbs. whey ; No. 2 with 22 lbs. of skimmed milk ; and No. 3 with 17.6 lbs. milk and 3.9 lbs. cream. The average consumption and the gain in weight per day were as follows : OOHSUUED. NutritlTe Ratio.t 1: Oflin per day. Lbs. Founds of Organic Substance, Lbs. Protein. Lba. Sugar. Lbs. Pat. Lbs. matter to lib. of growth. No. 1. . . 2.3 0.54 1.29 0.51 4.8 ,1.88 1.35 No. 2... 2.0 0.70 1.03 0.33 3.3 1.14 1.88 No. 3... 3.0 0.73 1.03 1.22 5.6 3.38 0.97 It win be seen that the gain in weight was strikingly different, according to the food used. The least gain was made in the second experiment, where the nutritive ratio was very narrow. In this case there is little doubt that, in spite of the comparatively small protein consumption of young animals, a considera- ble waste of protein must have taken place, resulting in a small gain. * Wolff : " Landwirthschaftliche Fiittemngslehre," p. 153. f In calculating^ the nutritive ratio, the fat has been converted into its "starch-equivalent" by multiplying it by 3.5. The milk used in these experiments was rather rich in nitrogen and poor in fat. With more average milk, the nutritive ratio in No. 1 and No. 3 would have been still wider. 444 MANUAL OF CATTLE-FEEDIlira^ In the third experiment the food was the same as in the second, with the addition of a pound of fat per day. This addition of fat evidently rendered the protein consumption less, while also supplying more material for fat formation, and, as a result, a very marked gain was produced. The amount of organic matter required to produce a gain of one pound was also less in this case than in either of the others, and somewhat less than in Soxhlet's experiments. A comparison of the first and second experiments is es- pecially instructive. The total amount of nutritive matters consumed in the two cases was about the same, but the wider nutritive ratio of the first experiment caused a greater and more economical gain. Sugar in Place of Fat. — The first of the above ex- periments is particularly interesting as showing that a satisfactory gain may be brought about by a ration com- paratively poor in protein, but having a rather wide nutri- tive ratio, and also that sugar may be advantageously used instead of the more costly fat to produce this wider nutri- tive ratio. This result is of practical value, because it seems to indicate quite clearly that even with pretty young calves a portion of the milk, perhaps half, may be replaced "by whey,* or perhaps that skimmed milk,f with the addi- tion of sugar or starch, may be used instead of whole mUk. It is questionable, however, whether the fat of the milk can be whoUy replaced by carbhydrates with safety. Fat * In the manufacture of cheese, most of the casein and fat are re- moved from the milk in the curd, while the whey contains nearly all of the milk-sugar, together with a little fat and protein. (See Table of Composition of Feeding-stufis in Appendix. ) f Skimmed milk has lost chiefly fat, which, on the above plan, would be replaced, at least to a certain extent, by starch or sugar. MANUAL OF CATTLE-FEEDING. 445 is the most concentrated of all the non-nitrogenous nutri- ents, and in the finely divided state in which it exists in milk is probably very easily digestible by the young ani- mal. In addition to this, the greater palatability of nor- mal milk is an important factor in determining the effect of feeding, as has already been explained in connection with other fodders. Whole milk is the natural fodder of young animals, and the one whose composition must be imitated as closely as possible in all attempts to substitute other materials for it, and which, for the first two weeks at least, should, if possible, form the only food. During the first four to six weeks, an increase of 1 lb. live-weight is obtained, on the average, with about 10 lbs. of milk (1.25 lb. dry organic matter). At first the quantity of milk is a little less, and toward the close a little more. Since, however, the composition of milk is variable, the amount of fat, especially, varying from 2 to 5 per cent., and the nutritive ratio consequently from 1 : 3.3 to 1 : 5.5, it is easy to see why the effect produced by the same quantity of milk should vary considerably in different cases. Substitutes for Milk. — It is sometimes desirable to replace the milk partly or wholly by other feeding-stuffs. In doing this, it should be the aim to compound a ration approaching milt as closely as possible, not only in com- position, but also (and this is quite as important) in prop- erties. It should be easily digestible, liquid if possible, and should be fed warm. This is not the place to enter into a discussion of the various substitutes for milk Avhich have been proposed. It is our office simply to point out the principle on which they should be based, viz., as close an imitation of the composition and properties of normal milk as possible. The tables of the composition and digestibility of feed- 446 MANTJAL OF CATTIiE-FEEDINQ. ing-stujBfs contained in the Appendix will aid in forming a judgment as to how far these conditions are fulfilled in any proposed substitute, while actual trial alone can fix its true practical value. Weaning. — ^It is one of the feeder's chief problems to bring about the change from exclusive milk feeding to other fodder in such a manner as not only to cause no fall- ing off in the condition of the animal, but so that a con- stant increase in the hve- weight shall take place during, or at least immediately after weaning. This can only be accomplished by making the change as gradual as possible and replacing the milk by substitutes of suitable digesti- bility, palatability, and nutritive quality. Crushed and boiled flaxseed is at first very well suited to this purpose. Later, oil cake or palm-nut cake, and also oats, barley, malt sprouts, etc., can be profitably used, while by feeding the finest and tenderest hay the animals are gradually ac- customed to coarse fodder. When the calves can be early put upon good pasturage the weaning will accomphsh itseK ; but where this is not the case and they must be stall-fed, more care is demanded. At first the same nutritive ratio should be maintained as in average milk, or, at most, it may be a little widened to- ward the end of the weaning. The fat of the milk, how- ever, may be pretty rapidly replaced by a corresponding quantity of easily digestible carbhydrates, without, how- ever, making the change too sudden. In this way the complete weaning of the calves may be accomplished by the end of the ninth or tenth Veek, or even earlier. After Weaning. — ^Af ter weaning it is advisable to con- tinue for some time the use of quite concentrated food with a nutritive ratio of 1 : 5 — 6. Soxhlet's experiments (p. 439) render it probable that MANUAL OF CATTLE-FEEDING. 447 all young and growing animals utilize a larger proportion of the protein of their food than mature animals, and only lose this power gradually as they approach maturity. A growing animal, then, may economically receive a relative- ly large proportion of proteinj thus placing at its disposal an abundance of material for forming new tissue, while as it gro#s older either the amount must be decreased or more non-nitrogenous nutrients must be added to the ra- tion in order to protect the protein from waste, i. e., the nutritive ratio must be widened. Moreover, the stomach of the young animal does not at once become capable of accommodating and digesting large masses of fodder, and hence its food must at first occupy a comparatively small bulk — ^must contain much nutriment in a small volume. It is desirable also . that the fodder should not be too watery, for much the same reasons as those adduced under fattening. When the animals have reached the age of six to nine months, however, the fodder may be gradually made more bulky and less rich in protein and nutritive matters in gen- eral, and roots may now be used more freely than before. To obtain good milk cows, especially, the rich feeding must not be continued too long, as it tends to develop an inclination to fattening rather than to milk produc.tion. If, on the other hand, the animals are to be fattened, it might be an advantage to continue a pretty rich feeding. In the feeding standards given in the Appendix these considerations have been taken into account. It is to be remarked, in regard to these standards, that they have their basis rather in practical experience than in exact scientific investigation, and, like aU feeding standards, are subject to modification both by the experience of the user and the results of f m-ther investigation. 448 MANUAL OF CATTLE-FEEDING. i 3. Lambs. Quality of Fodder. — ^Young lambs increase in weight relatively more rapidly than calves, and easily suffer from in- sufficient food, and hence great care must be obsenred in feed- ing them. This is especially the case as regards the choice of the coarse fodder during and immediately after weaning. Lambs do best upon good pasturage. If fed in the stall, they must receive only the best and tenderest hay. If the latter is even slightly too coarse or is unpalatable from any cause, such as unfavorable weather during its making, the animals will not eat a sufficient quantity, and will be strik- ingly retarded in their development. Even hay of aver- age quality requires the addition of grain, best of oats, or of some other nitrogenous feeding-stuff. Feeding fok Maintenance. — Wolflf's Sxperiments. — Some experiments made by WoKf,* at Hohenheim, on the digestibility of fodder by sheep of two different breeds, are also of value in fixing a feeding standard for lambs. Four lambs of the so-called Wurttemberg bastard breed, about five months old and weighing about fifty pounds per head, were used. Similar experiments were attempted on Southdown lambs, but were interrupted by sickness of the animals. Two of the four lambs were fed with hay ex- clusively for nine months. The other two received, in addition, graia and oil cake, and fattened quite rapidly, while the first two received only maintenance fodder. We will take up first the results obtained on the hay-fed lambs, omitting, for the present, the question of fattening. The experiment was divided into five periods, in each of which the composition and digestibility of the hay were carefully detennined. In each period the animals re- *Landw. Jahrbiichei, II., 221. MAIirUAL OF CATTLE-FEEDING. 449, ceived as much hay as they would eat, the amount con- sumed being, of course, carefully determined. In the first and second periods the fodder was a very excellent quality of early-cut meado_w hay, nearly YO per cent, of the total organic matter of which was digested. In the third, fourth, and fifth periods it was rowen, which, indeed, was of good quality and was well digested, but which was unpalatable to the animals after the better fodder which they had received, the consequence being that they ate con- siderably less and gained little or nothing in weight. The following table shows the average consumption of fodder per day and head, the amount of nutrients actually di- gested, and the gain in weight, for each of the five periods. Age. Months. Average weight. Lbs. Hay eaten. Lba. - Digested per Day. Gain per Period. Protein. Lb. Fat. Lb. Carbhy- drates. Lb. day. Lb. 1 .... 2.... 3.... 4.... 5.... 5-6 6-8 8-9 9-13 12-14 58.5 66.8 72.3 73.0 76.3 1.89 3.01 1.71 1.46 1.89 0.185 0.198 0.135 0.101 0.133 0.020 0.023 0.038 0.031 0.031 0.913 1.121 0.799 0.710 0.888 0.241 0.153 0.058 0.003 0.100 Eflbct of Change of Podder, — In the first and second periods the gain was very satisfactory, but with the change of fodder at the beginning of the third period the amount eaten sank, and the gain per day dropped to nearly a third of the previous figure. In the fourth period this was still more marked,* the fodder being barely sufficient to sustain the animals, and only in the fifth period, after four months, did the consumption of hay and the gain of weight rise again. A more striking example could hardly be given 450 MANUAL OP CATTLE-FEEDING^ of the need of care in changing from a good to a poorer fodder in the case of young animals. Feeding Standards. — It is probable that if the animals had been able to eat as mnch of the second fodder as of the first, or if some fodder which contained about the same amount of nutrients but was more palatable to the ani- mals had been used, the gain of weight would have con- tinued regularly, decreasing gradually with increasing age. On the assumption that the results of the first, second, and fifth periods are normal, the feeding standards given in the Appendix have been calculated by Wolff. They are intended for animals of medium fineness of wool, and which, when full grown, weigh 90 to 100 lbs. Such ani- mals, when fed in this way, will, on reaching the above weight, be in a well-fed condition and ready either for fat- tening or for wool production. In the above experiments this result was obtained by the use of hay alone, but this course will only succeed when the hay is of very superior quality. When this is not the case, and a good pasture is not available, an addi- tion of grain must be made to the hay ration, in order to bring the quantity of nutrients up to the standard. It will be noticed that, according to the feeding stand- ards deduced above, the quantity of protein required per day and head decreases as the age of the animals increases, and that the amount of the non-nitrogenous nutrients re- mains about the same, notwithstanding that the live-weight is continually increasing. Young animals, as already stated (p. 438), need a rela- tively large amount of total dry matter and of digestible sub- stance in their fodder, and gain weight with corresponding rapidity, while later, the necessary amount of food decreases quite rapidly, as does also the increase of weight. The MANTJAL OF CATTLE-FEEDING. 451 more rapid gain in weight at first is doubtless caused, in part at least, by the power of the young animal to appro- priate to the building up of its body a large proportion of the very considerable amount of protein contained in its fodder. Another circumstance, however, must be taken into account, viz., the fact that the flesh of young and rapidly growing animals contains a larger percentage of water than that of older animals. This fact shoidd always be borne in mind in comparing the effects of a ration upon young and old animals simply by the gain of live-weight. Weiske's Experiments. — Some recent experiments by Weiske * on the feeding of lambs are of interest in this connection. During nine consecutive periods of about one and one-quarter months each, covering the time from the fourth to the fifteenth month of the animals' age, the fod- der of the animals was carefully weighed out each day, and any portions left uneaten were also weighed and deducted. At the close of the ninth period came a pause of about nine months, after which a tenth experiment was made, the animals being then full-grown. The fodder consisted at first of hay and peas. As the experiments progressed the quantity of the former was gradually increased and that of the latter diminished, till in the eighth, ninth, and tenth periods the ration was com- posed exclusively of hay. In each period the live-weight, the digestibility of the fodder, and the excretion of nitro- gen in the urine were determined, the investigation of the excrements and the weighing extending over eight days. That the fodder was abundantly suificient was shown by the regular increase in weight, and also by the fact that the animals gained weight faster than similar animals from the same herd on good pasturage. * Landw. Jahibticher, IX., 205. 452 MANUAL OF CATTLE-PEEDrBra. The experiments were begun with two animals, but, owing to various causes, accurate results could in several- cases be obtained only on one. The numbers in the fol- lowing table refer to lamb No. II., unless the contrary is stated. The ages given in the table are only approximate ; the live-weight is in each case the average of eight weigh- ings made toward the close of the period. Pbb Head. Age. Months. Live- weight. lihB. DiOEBTBa) PEB DAT. Nntr. Batio. 1: Gain pke Dat. Period. Protein. Lb. Fat. Lb. Carbhy- diates. Lb. Live- weight. Flesh. Lb. 1 2 3 4 5 6 7 8 9*.... 10 4-5i 5i-6i 64-7f 7f-9 9-lOi loj-iii lli-12f 13i-14 14-15 24 45.0 56.2* 63.5 71.7 77.0 77.6 83.6 89.1 85.8 126.5 0.17 0.18 0.18 0.20 0.18 0.18 0.18 0.17 0.16 0.15 0.03 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.04 0.06 0.74 0.93 0.90 0.98 0.95 0.94 0.96 0.99 0.98 1.18 4.8 5.7 5.6 5.4 5.8 5.8 6.0 6.6 6.8 8.9 0.28 0.27 0.23 0.30 0.13 ■0.09 0.13 0.16 0.17 0.17 0.15 0.18 0.15 0.13 0.19 0.16 0.14 These figures agree as closely as can be expected in ex- periments of this sort with the results obtained by Wolff, and show the correctness of the feeding standards recom- mended by him. The amount of digestible protein required per day and head by lambs is shown by these figures to be essentially the same in all the" periods, notwithstanding the increase in * Lamb No. I. MANUAL OF CATTLE-FEEDING. 453 weight, while the quantity of non-nitrogenons nutrients increases slightly. In "Wolff's experiments, both the pro- tein and the non-nitrogenous nutrients decreased in quan- tity toward the end of the experiments. As already noted, Weiske's lambs grew faster than others of the same herd, and it is not unlikely that slightly less food would have given satisfactory results. The gain of live-weight diminished as the animals ap- proached maturity, while the protein consumption, as well as the gain of flesh, per head, was found to be nearly con- stant throughout. If, however, the results are calculated per 100 pounds live-weight, as in Soxhlet's experiments on calves, we have a somewhat different showing. In the following table this has been done. Pbb 100 Pounds Live- weight. SiSBBIED PEB DAT. Gain of weight Pffday. Lba. Protein consump- tion per day. Lbs. Gain of protein per day. Lbs. Gain of Period. Protein, Lbs. Fat. Lba. Carbhy- drates. Lba. perct. of amount digested. 1 0.38 0.07 1.67 0.73 0.29 0.09 23.7 2 0.33 0.07 1.66 0.54 0.26 0.07 21.2 3 0.38 0.06 1.41 0.41 0.23 0.05 17.9 4 0.28 0.06 1.86 0.31 0.22 0.06 21.4 5 0.24 0.05 1.23 0.17 0.30 0.04 16.7 6 0.23 0.06 1.22 0.13 0.19 0.04 17.4 7 0.23 0.05 1.15 0.17 0.17 0.05 23.7 8 0.30 0.05 1.11 0.19 0.16 0.04 30.0 9 0.19 0.06 1.09 .... 10 0.13 0.05 0.93 .... 0.10 0.02 16.7 "We see that as the animals grew older the relative amount of food consumed decreased, and that the gain of 454 MANUAL OF CATTLE-FEEDING. weight likewise became less rapid. The protein consump- tion, too, decreased, in consequence of the diminished supply of this nutrient, and the gain of protein, though varying somewhat from period to period, also showed a de- cided decrease. The results regarding the percentage of the total digested protein which was retained in the body contrast strongly with those obtained by Soxhlet on suck- ing calves (p. 439), and show that the protein consumption increases quite rapidly in growing animals, and even at a comparatively early age becomes much greater than the gain of protein by the body. The respiratory products were not determined in these experiments, but from the observed gain of nitrogen, sul- phur, and mineral matters, it was calculated that the in- crease in weight in the first nine periods (53.9 lbs.*) had approximately the following composition : LbB. LbB. Drv Drotein f exclusive of wool) 8.29 2.43 37.03 6.15 53.90 Flesh " " 34.54 Pure wool f water-free^ • Crude wool 5.47 Fat and water Fat 8.10 " " less those of crude wool Total gain 5.79 53.90 * The gain in weight is the difference between the live-weight at the beginning of the first and the end of the ninth period, and hence is greater than would appear from the table on page 452, which gives only the (M>erage weight for each period. MANUAL OF OATTLE-FEEDING. 455 These figures are interesting as showing the large gain of flesh made by the young animals, while, as we have seen, mature animals, even when highly fed, gain chiefly fat. Fattening. — WolflPs Experiments. — In the experi- ments by Wolff, partially described on page 448, two of the lambs received, in addition to the hay, oats, and oil cake, and at the close of the experiment were found to be well fattened. The following table shows the total amount of fodder (water-free) eaten, the amount of digesti- ble nutrients, and the gain in weight, per day and head, for the several periods : Age. Months. Average live- weight. Lbs. Total fodder. Lbs. DiOESTED. Nutr. Ratio. 1: Gain Period. Protein, Lb. Fat. ■ Lb. Carbhy- drates. Lb. per day. Lbs. 1 5-6 6-8 8-9 9-13 13-14 59.7 70.7 78.9 84.8 95.8 1.99 3.03 1.91 1.83 1.76 0.31 0.34 0.31 0.19 0.19 0.08 0.08 0.10 0,06 0.08 0.97 1.03 0.93 0.91 0.89 5.6 5.1 5.6 5.6 5.7 0.36 3 34 3 0.07 4 13 5 19 In the last three periods the consumption of fodder fell off considerably, especially if we take into account the in- creased weight of the animals. The average consumption of digestible protein per day and head was 0,21 pound, and the nutritive ratio did not vary greatly from 1 : 5.6. We shall not, thei-efore, err greatly if we say that a ration containing, per day and head, about 0,20 pound of digestible protein, and having a nutritive ratio of about 1 : 5.6, and fed constantly from the age of six months on, 456 MAKUAL OF CATTLE-FEEDING. irrespective of the increase in weight, will, in eight to nine months, yield animals weighing in the neighborhood of 100 lbs., and well fattened. Bioher Feeding. — By richer feeding a still more rapid gain may be obtained. In some experiments by Stohmann,* lambs seven to eight months old were fed for five months upon straw, potatoes, clover hay, and oil cake. These feeding-stuffs were combined into four different rations, two (Nos. 2 and 3) containing, per day and head, on the average, 0.28 lb. of digestible protein, and the other two (Nos. 1 and 4) about 0.38 lb. The quantity of non-nitrogenous nutrients was. such that the nutritive ratio of one ration of each pair was wider than that of the other, as shown by the table on the opposite page. All the animals gained weight rapidly, but it was ob- served that the rations containing the larger amount of protein, produced, as was to be expected, the greatest effect (compare p. 399 et seq.), and also that the wider nu- tritive ratios gave better results than the narrower, a thing which was also to be expected. The latter fact was espe- cially noticeable after the animals were shorn at the end of the fourth month. After this, 0.46f lb. of protein per day, with a nutritive ratio of 1 : 3.9, not only gave a poorer result than about the same quantity with a ratio of 1 : 4.3, but hardly a better than 0.33t lb. of protein with a nutritive ratio of 1 : 5.3. * Jour. f. Landw,, 1867, p. 133; " Emahrmig der Landw. Nutz- thiere," p. 439. f The quantities of protein first given are the average amounts for the first four months. The actual quantity vr^as gradually increased with the growth of the animals, and hence the average for the last month is higher. MANUAL OF CATTLE-FEEDING. 457 The following table gives the average amount of digesti- ble protein and non-nitrogenous nutrients, the nutritive ratio, and the gain in weight, per day and head, both be- fore and after shearing. The experiments extended over four months before the shearing and one month after. Before Sheaking. Lotl. Lota. Lots. lK>t4. 0.38 1.54 1:4.1 0.25 0.28 1.56 1:5.6 0.21 0.28 1.36 1:4.9 0.17 0.38 Digestible non-nitrogenous nutri- 1.41 1:3.7 Gain oer dav. Lb 0.21 After Sheabino. Digestible protein. Lb Digestible non-nitrogenous nutri- ents. Lbs. Nutritive ratio Gain per day. Lb. . . Average live-weight. Dressed weight in per cent, of live- weight Lbs. 0.48 0.35 0.33 2.04 2.02 1.76 1:4.3 1:5.8 1:5.3 0.28 0.25 0.23 95.00 92.00 86.00 58.1 57.4 56.2 0.46 1.80 1:3.9 0.24 92.00 53.1 It was, of course, to be expected that, other things being equal, the ration furnishing' the most protein would give the best results. A limit, however, exists in the fact that the animals can consume only a certain amount of food, and that consequently it is impossible to feed enough non- nitrogenous matters to prevent a waste of protein when a very large amount of the latter is given. 30 458 MANTTAL OF OATTLE-FEEDHiTG. According to these results, a ration containing 0.28 to 0.38 lb. of digestible protein, per day and head, and hav- ing a nutritive ratio of about 1 : 6, will produce in about five months the same result as the poorer ration used in Wolff's experiments (p. 455) did in nine. To attain such a result, however, care must be exercised in the choice of the feeding-stuffs, so as to ensure the com- plete consumption of the ration. Moreover, the cost of such feeding is an important consideration, and the farmer will do well to consider whether it would not be cheaper to use the poorer ration, or even to defer the real fattening until later. (See p. 402.) It should be added that these feeding standards, like those for maintenance, apply to animals of medium fine- ness of wool, weighing, when full grown, 90-100 poxmds. Fine-wooled animals generally require rather more food than coarse-wooled, and heavier animals need more than lighter. g4. Pigs. Variations in Fodder. — In regard to the feeding of pigs to be used for breeding, or which are to be fattened after reaching maturity, no exact experiments have been made. More commonly, however, pigs receive a full fattening fodder from the time they are weaned, and the experi- ments on the fattening of pigs are quite numerous. These experiments have shown that the fodder of the pig may vary more in its composition than that of almost any other domestic animal, resembling in this respect that of car- nivorous animals. It may be toaade very rich in protein, having a nutritive ratio of 1:2, or it may safely be made pretty rich iq digestible carbhydrates. Adding to this the MANUAL OF CATTLE-FEEDING. 459 relatively large amoimt of fodder consumed by the pig, it becomes plain that both the nntritive effect and the cost of the feeding may vary greatly, and that consequently the feeding standards for pigs nmst be still more general in their nature than those for other animals. Nutritive Ratio. — All experiments on pigs agree in showing that with young animals a na/rrow nutritme ratio produces the most rapid gain with the least expenditure of fodder, while as the animals grow older the best results, both as to rapidity of gain and' quality of product, are generally obtained by using a somewhat wider ratio. Of the numerous experiments illustrating this, the fol- lowing by Lehmann* may serve as an qxample. The feeding-stuffs used were skimmed milk, peas, oats, barley, rye bran, and potatoes. Six animals were divided into three lots of two each : Lot I. received in each period a fodder having a nutritive ratio of about 1:4; Lot II. one having a nutritive ratio of about 1:6; and Lot III. one having a ratio of 1 : 8. The following table contains the principal results of the experiments : Period I.— 13 Days (Age : 68-81 Days). Feb DAT asd Head. Nntr. ratio. 1: To Pkodtjoe ji Gaik of 100 Pounds. Lot. Average live- weight. LbB. Gain. Lb. Dry matter ot fodder. Lbs. Dry matter. Lbs. Protein. Lbs. Carbhy- drates. Lbs. Fat Lbs. I... 11.. in.. 46.8 44.6 44.6 0.85 0.76 0.59 2.32 2.31 2.35 3.93 6.13 8.27 301.95 333.85 486.59 59.10 44.95 45.10 210.12 258.72 356.40 9.01 6.81 6.71 ' WolfE: "Bmahrnng der Lanclw. Nutzthiere," p. 466. 460 MANUAL OF OATTLE-FEEDIWG. Period III.*— 39 Days (Age: 133-152 Days). Feb DAT AKS Head. Nntr. ratio. 1: To PnoDroB A Gain of 100 Foxrass. Lot. Aver&ge Uve- weight. Lbs. Gain. Lb. Dry matter of fodder. Lbs. Dry matter. .Lbs. Protein. Lbs. Carbliy- drstea. Lbs. Fat. Lbs. I... II.. m.. 110.9 108.1 90.0 1.31 0.97 0.85 4.44 3.79 3.41 4.18 6.35 7.80 374.55 431.31 439.01 69.63 56.33 44.55 357.40 333.09 357.17 13.64 10.33 7.48 Period IV,— 35 Days (Age : 152-177 Days). I... 143.6 1.13 4.65 3.94 465.19 90.97 328.29 14.08 n.. 136.7 1.10 4.36 6.13 435.71 58.74 337.59 8.91 III.. 113.0 0.77 3.11 9.09 445.38 43.24 368.28 6.27 Period V. — 45 Days (Age : 177-222 Days). I... 190.6 1.41 5.33 3.64 416.24 85.91 383.26 12.87 II.. 189.3 1,71 5.40 5.78 347.37 49.38 264.66 8.36 III.. 156.5 1.54 5.07 7.04 363.34 43.45 286.33 7.93 Period VL— 66 Days (Age: 347-313 Days). I... 287.1 1.14 6.03 4.05 682.45 110.99 408.33 16.39 II.. 293.9 1.56 5.98 6.36 421.19 54.89 328.90 8.03 III.. 241.2 1.07 4.85 8.76 498.52 49.17 409.97 8.14 , An inspection of the table shows that up to Period IV. the fodder having the narrowest nutritive ratio produced * The results of Period II., of 42 days, are omitted because sickness among the animals rendered them of doubtful value. MANUAL OF CATTLE-FEEDIXG. 461 the greatest gain and with the least expenditure of fodder. It is also noticeable that in nearly every ease the animals ate more of the fodder in proportion as its nutritive ratio was narrower. In Period IV. the ration with a nutritive ratio of 1 : 6, produced a given gain with the least expendi- ture of fodder, although the gain per day was greatest in Lot I., o.wing to the greater amount of fodder eaten. In Periods V. and VI. the advantage is decidedly with the nutritive ratio 1 : 6, both as to the gain made and the ex- penditure of fodder. Very similar residts have been obtained by numerous other observers. In all cases a narrow nutritive ratio during the first few months of feeding has given the best results, while widening the nutritive ratio as the animals grow older has almost always been found advantageous. Thus Heiden,* in his extensive feeding experiments on pigs, found that while peas and sour milk formed an ex- cellent fattening fodder for pigs up to the age of about four months, much better results were reached after that time by the addition of potatoes to the ration. Feeding Standards. — The feeding standards for pigs given in the Appendix are deduced by, "Wolff from the results of a large number of feeding trials. The narrow nutritive ratio there recommended for young pigs, and its gradual widening, are, as we have just seen, in accord with the results of experiment; the total quantity of fodder eaten Is most naturally and simply determined by the appetite of the animal. Although these highly nitrogenous rations caxise the most rapid gain in weight, they appear of questionable advisa- bility in so far as the animals are rendered more liable to * "TTntersuchungen uber die zweckmaBsigste EmahTung des Schwei- nes," EannoTer, 1879. Heft II., p. 93 et seq. 462 MANUAL OP CATTLE-FEEDING. over-feeding and to various diseases than when the fodder is poorer in protein. For the sake of greater security it may oftentimes be advisable to reduce the amount of albuminoids somewhat from that given in the standards, and to begin at once with a nutritive ratio of 1 : 4.5 or 1 : 5, widening it gradually after the fifth or sixth month tUl it reaches 1 : 6.5. Another and very important point to be considered in the use of these nari'ow nutritive ratios is that of cost. The table on page 460 shows that although a given increase in weight was produced with the least fodder when that fodder had a narrow nutritive ratio, the quantity of pro- tevn required was in every case greater, while that of the carbhydrates was correspondingly less. As a general rule feeding-stuffs rich in protein, such as are necessary in com- pounding a ration having a narrow nutritive ratio, are rather costly, while the carbhydrates are comparatively cheap. The less cost of a ration having a wide nutritive ratio might, then, render its use more economical, in spite of the larger amount of it required to produce a given increase in weight. All these points, as well as practical considerations concerning the most suitable feeding-stuffs, must be taken account of in iixing on the most suitable ration for a particular case, and they obviously offer a wide field for the exercise of intelligence and good judgment. ? 5. InOBGAOTC NtlTBIBNTS. Importance. — Hitherto we have considered only the demands of various animals for the several organic nutri- ents. The greater quantity of these renders their impor- tance more obvious, but at the same time the mineral ingredients of feeding-stuffs are no less essential, as has MANUAL OP CATTLE-FEEDING. 463 already been pointed out on pages 20 to 24. This is especially the case with growing animals, which have not only to replace the loss of these substances which is con- tinually taking place, but also to provide material for new growth, both of bone and of the soft parts of the body. Supply in the Food. — Although all the mineral in- gredients of the body are essential, there are five substances which, on account of the large quantity of them which is required, may be said to be more important than the others ; these are soda, potash, lime, phosphoric acid, and chlorine. Of these, sodium (the basis of soda) and chlorine, com- bined to form common salt, occupy to a certain extent an exceptional position, as has already been explained, and the necessity for a sufficient supply of salt is generally un- derstood and acted upon.* Potash is contained in sufficient quantity, and generally in excess, in all ordinary feeding- stuffs. Lime and phosphoric acid, though they exist in large quantity in many feeding-stuffs, may sometimes be deficient, and these two substances are the principal ones which need be considered. Of the common fodders, grass and hay, particularly clover, are quite rich in lime but comparatively poor in phosphoric acid. The same is the case with the straw of the legumes. The straw of the cereals contains rather more phosphoric acid than that of the legumes, but still has an excess of lime. Eoots, being so watery, have rela- tively little ash, but contain more phosphoric acid than lime. The grains, and indeed aU seeds, are rich in phos- phoric acid and poor in lime. Circumstances under -which a Iiack may occur. — These considerations make it evident that when an animal is fed largely or exclusively on coarse fodder, particularly 464 MANUAL OP CATTLE-FEEDING. on meadow or clover hay, a lack of phosphoric acid may occur, while lime would be plentifully supplied. H, on the other hand, much grain, roots, and straw or chaff are fed, with little hay, a lack of lime might result. It seems not unlikely that this is sometimes the cause of the " bone hunger," which causes cattle to seek out and chew bones. Calves and lambs are commonly fed on hay and grain, and under these circumstances experience has shown that a lack of lime or phosphoric acid is not to be feared, since these two classes of feeding-stuffs supply each other's defi- ciencies in this respect, grain containing much phosphoric acid and little lime, and hay much lime and little phos- phoric acid. Pigs, on the other hand, are frequently fed almost ex- clusively on grain and potatoes, with the addition of sour milk or skimmed milk. All these feeding-stuffs contain large quantities of phosphoric acid and but little lime (with the exception of milk), and experience has shown that the addition of a small amount of lime to the feed of pigs, either as chalk or carefully sifted leached wood ashes, is often of great value and is to be regarded almost as a necessity. How Supplied. — ^Very few experiments have been made on the amount of inorganic nutrients demanded either by young or mature animals, although it has been fully proved that a lack of them may be a cause of backwardness in growth, or even be fatal. Experience shows, however, that such cases are rare, and it is only when the fodder consists largely of materials known to be poor in lime or phosphoric acid that their occurrence is to be apprehended. Under such circumstances a lack of lime is easily Sup- plied by a " lick stone " of chalk or soft limestone, or by MANCTAL OF CATTLE-FEEDING. 465 the addition of chalk or leached ashes to the fodder. When a lack of phosphoric acid is suspected, the use of bone meal is commonly recommended. The bone should be ground exceedingly fine, and even then the danger that it may con- tain diseased bone is not excluded, though the latter would probably be reduced by the use of bone from which glue has been made, and which has consequently been cooked. A safer material than bone meal is chemically prepared precipitated phosphate of lime, when obtainable. Better than either of these methods, however, is the use of fodder containing more phosphoric acid. This may easily be brought about by the use of some bye-fodder which is rich in this substance, such as fish scrap or dried blood, oil cake, or the bye-products of the grains, ao* CHAPTEK yn. THE CALCULATION OF RATIONS. In the foregoing chapters we have been chiefly occupied with a consideration of the quantities of digestible nutri- ents which are required in the food of farm animals for various purposes, and have only incidentally touched on the question of how these are to be supplied. In this chapter we shall consider the manner of compounding a ration which shall contain the quantities of digestible nutrients called for by a feeding standard. When animals are pastm'ed, or when they receive but a single kind of fodder, as good hay, for example, there is evidently no occasion for the use of a feeding standard ; but when, as is usually the case in stall-feeding, the avail- able coarse fodder is deficient in protein and must be sup- plemented by bye-fodder, a feeding standard can afford valuable aid in determining the proper proportions of the various feeding-stuffs. As an example, we will take the feeding of milk cows according to Wolff's feeding standard, viz. : Digestible protein 3.5 pounds. " fat 0.4 " " carbhydrates 13.5 " Total dry matter 24.0 " Nutritive ratio 1 :5.4 MABTUAL OF OATTLE-FEEDIITG. 467 Suppose that there is available for the daily fodder of the cows, per 1,000 lbs. live-weight, twelve pounds of hay, six pounds of oat straw, and twenty pounds of mangolds, and that brewers' grains can be had cheaply. Plainly what we have to do is, first, to ascertain how much digestible matter the available amounts of coarse fodder and roots win furnish, and second, to calculate how much must be added to this ration to bring it up to the feeding standard. "We first need to know the percentages of digestible protein, carbhydrates, and fat contained in each of the feeding-stuffs, and for this purpose we must avail our- selves of the results obtained by others, since it is obvious- ly impracticable to make direct digestion experiments. For this purpose we make use of tables of the composition and digestibility of feeding-stufifs, like those given in the Appendix, in which the results of all available analyses and digestion experiments are condensed. The tables given in the Appendix are essentially those of Julius Kiihn ; they show both the average composition and digestibUity of the common feeding-stuffs and also the ob- served rojige of variation in these respects. Wolff, in his table, gives directly the average percentage of digestible nutrients contained in each fodder, thus facilitating the cal- culation of rations. This convenience, however, is attained only by assuming a uniform composition and digestibility for each feeding-stuff, assumptions which, as we have seen, and as Kiihn's tables show, are far from being true, particu- larly as regards coarse fodder. Moreover, comparatively few feeding-stuffs have been tested as to their digestibility, that of the others being only estimated. Under these circum- stances the most rational method is to endeavor to form an estimate in each particular case of the amount of digestible matter likely to be present in the fodder. This method, 468 MANUAL OF CATTLE-FEEDING. though less simple than merelj taking the average per- centages of digestible ingredients from a table, is likely to give results corresponding more closely to the truth, when intelligently carried out, and has * also the advantage of keeping prominently before the mind the approximate character of the calculation. Two facts wUl serve to aid us in forming a judgment as to the amounts of digestible nutrients which a given fodder win furnish : first, the digestibility of a feeding-stuff de- pends largely on its chemical composition, and second, the composition of coarse fodder is quite variable, while that of the concentrated fodders is more constant. Our first step, then, in the case supposed, is to form an estimate of the composition of the hay, straw, and roots which are to form the basis of the ration. By far the most satisfactory method of doing this is by the help of a partial analysis, and such analyses of feeding-stuffs might appro- priately be undertaken by the Experiment Stations now begiiming to be established in our midst. In the case of a coarse fodder, like hay or straw, determinations of water, protein, and crude fibre should be made ; in concentrated fodders water and protein, and in some cases fat, should be determined. For the ash and fat of coarse fodders and the ash and crude fibre of concentrated fodders the average numbers may safely be taken, while subtracting the sum of the protein, crude fibre, fat, and ash from 100 will give the approximate amount of nitrogen-free extract. In this way the composition of the feeding-stuffs in question may be determined with sufficient accuracy for the purpose. When it is not practicable to procure an analysis of the feeding-stuffs to be used, their composition must be esti- mated as well as may be by the aid of the table in the Ap- pendix. This table shows the extremes of composition MANUAL OF CATTLE-FEEDING. 469 yet observed, and also gives the probable average composi- tion. In using the table, it is to be remembered that in many cases the extreme numbers represent the composi- tion of exceptional samples, and that the ordinary range of composition of the material under consideration may be considerably less than appears from the table. It is sel- dom that ordinarily good fodders will reach either the maximum or minimum of any ingredient, and the judg- ment of the feeder will be exercised in determining how great a variation from the average, is to be expected in the particular case under consideration. To this end he will take into account the richness of the soil on which the fodder was grown, its stage of growth, and, in short, all those influences mentioned in Part II., Chapters 11. and in., as affecting the composition of coarse fodder in particular. Under meadow hay and clover hay, in the table, "Wolff's classification of these feeding-stuffs has been introduced. The " inferior " hay corresponds to that cut at an advanced stage of growth, or damaged by rain, or to the rank hay of low and shady places, and is characterized by a large percentage of crude fibre and a small percent^ age of protein. The better qualities of meadow and clo- ver hay are those obtained by early cutting from a rich soil and careful curing without loss. The figures given by Wolff for the protein of these classes of hay are consid- erably higher than those that have been found for American hay of apparently equal quality and containing no more crude fibre. This fact must, of course, be borne in mind in using Wolff's figures. In the case which we have selected for an example, we will suppose that by one or the other of the above meth- ods we have found the composition of our feeding-stuffs to be approximately the following : 470 HANTTAL OF CATTLE-FEEDING. Hay. Per cent. Oat Bfcraw. Percent. Mangolds. Per cent. Brewers' grains. Per cent. Water. 14 9 2 43 26 6 100 14 4 1 33 44 4 100 88 • 1 9 1 1 100 77 5 Fat 1 Nitrogen-free extract. . . . Crude fibre 11 S Ash 1 100 We have now to estimate the percentage of each of the ingredients of these feeding-stuffs which is digestible. The mangolds, like all roots and tubers, we may assume to be whoUy digestible. For concentrated fodders we may in most cases assume the average digestion coefficients, both because the digestibility of these fodders varies less than that of coarse fodder, and because fewer experiments have been made on them. On brewers' grains there have been no experiments, but our table gives estimates of their digestibility, andjbhese we accept provisionally in the absence of anything more exact. Of the non-nitrogenous ingredients of the coarse fodder, the fat is present in so small quantity that the assumption of average digestibility can introduce no serious error, while, as we have seen (p. 250), the nitrogen-free extract of a coarse fodder represents approximately the total quan- tity of digestible carbhydrates which it contains. Tliis fact, though only true in a general way, probably forms as accurate a basis for computations of digestibility as is fur- nished by the use of digestion coefficients, especially if ac- MANUAL OF CATTLE-FEEDING. 471 count be taken of the fact that the total digestible carbhy- drates are lUtely to exceed the nitrogen-free extract in coarse fodder which is rich in protein, and to faU short of it in feeding-stuffs having a low percentage of protein. There remains to be considered only the protein of the coarse fodder, and just this substance shows the greatest variations of digestibility. In general it is most digestible in those feeding-stuffs which contain most protein and least crude fibre, that is, in young and tender fodder, while in that which is old and woody or of coarse texture it is generally less digestible. In the case above supposed both the hay and straw are of nearly average composition, and we therefore assume average digestion coefficients for their protein, viz., 57 for that of the hay and 38 for that of the straw. A simple computation now shows us that 100 pounds of each of our four feeding-stuffs will furnish the following amounts of digestnble nutrients : Hay. Lbs. Oat straw. Lbs. Mangolds. Brewers^ grains. Lbs. Protein 5.13 43.00 0.93 3.51 33.00 0.30 1 10 4.S5 Carbhydrates 16.00 Fat 0.80 From these data we can easily calculate that the quanti- ties of hay, straw, and mangolds which we have assumed to be available per day and 1,000 lbs. live-weight, together with twenty pounds of brewers' grains, wiU furnish the cows with the following quantities of digestible protein, carbhydrates, and fat : 473 MANUAL OF CATTLE-FEEDIITO. Total dry BUbstance. Lbs. DiaESTIBLE. Albuminoids. Lbs. Carbhy- drates. Lbs. Pat. Lbs. 13 lbs. hay 10.33 5.16 3.40 4.60 0.63 0.09 0.30 0.85 1.76 5.16 1.98 3.00 3.30 0.11 0.03 30 lbs. mangolds 30 lbs. brewers' grains . . 0.16 Total 33.48 13.34 0.39 This ration falls short of the standard by about three-quar- ters of a pound of digestible protein. This must evidently be supplied by some nitrogenous bye-fodder, such as oil cake, fish, etc. Taking cotton-seed meal as an illustration, we find that the addition of two and one-half poimds of this feeding-stuff to the above ration, supposing the meal to have the average coinposition of the American article, and to be of average digestibility, wiU bring it up to the desired standard. Total dry substance. Lbs. DleEBTIBI,E. Albuminoids. Lbs. Carbhy- drates. Lbs. Fat Lb. Total as above 33.48 1.96 1.76 0.79 3.55 3.50 13.34 0.43 0.39 3.5 lbs. cotton-seed meal. 0.13 Total 34.44 34.00 13.76 13.50 0.43 Standard. 0.40 1 MANUAL OF OATTLE-FEEDING. 473 An exact correspondence with the standard need not be sought, and, indeed, it is evident from the foregoing para- graphs that such a correspondence, if attained, would be more apparent than real. The amount of non-nitrogenous nutrients may vary more than that of the protein, and the exact quantity of fat, in particular, is a matter of no special importance, provided too much is not fed. As a general rule, it is advisable to give too much rather than too little protein, both to ensure a sufficient supply of this important nutrient and for the reasons stated on pp. 280-283. In practice, of course, regard must be had to individual peculiarities of the animals, as well as to differences in weight. The most satisfactory plan would probably be to weigh out each day a sufficient^ supply for all the cattle ^ which receive the ration, and to distribute this amount among the animals according to their requirements. As a matter of course the animals must be carefully observed, and their supply of food modified according to the indica- tions thus obtained. The feeding standards, as already said, are not inflexible rules, to be blindly followed, but guides and indications which must be intelligently adapted to local and individual circumstances. The example given above serves to illustrate the manner of calctdating rations in accordance with a feeding standard. The chief points there given may be summed up in the following Rules fob the CALCnLATioN of Rations. 1. The composition of the fodders used is either ascer- tained by analysis or estimated from the table of the com- position of feeding-stuffs. 2. Tubers and roots are considered to be wholly di- gestible. 474 MANUAL OF CATTLE-FEEDING. 3. For the concentrated fodders, the average digestion co-efficients are employed in most cases. 4. The digestible carbhydrates of the coarse fodders are considered to be equal to the total nitrogen-free extract. 5. The digestibility of the protein of the coarse fodder is estimated from the composition of the latter, it being the greater the less crude fibre and the more protein the feeding-stuff contains. 6. By multiplying the percentage of each ingredient of the fodders by its digestion coefficient, the percentage of digestible matters in each feeding-stuff is obtained, the digestible nitrogen-free extract and digestible crude fibre being added together as carbhydrates. 7. From the data thus obtained we calculate, first, the quantities of digestible protein, carbhydrates, and fat in the amounts of fodder available, and second, what addi- tion of bye-fodder must be made to them to bring the ration up to the feeding standard. 8. If the dry matter of the tubers or roots entering into the ration does not exceed one-eighth that of the dry matter of the remaining fodder no deduction is made from the above figures. If, however, the dry matter of the roots or tubers exceeds this proportion, a deduction must be made from the amount of digestible protein of the ration as calculated, in the proportions indicated on page 285. These corrections may be considered sufficient when the coarse fodder consists chiefly of hay, and ample when the addition consists chiefly of roots and not of potatoes. On the contrary they are hardly sufficient when the ration contains much straw and potatoes. The depression of the digestibility, however, is decidedly diminished when the nutritive ratio of the whole ration, and especially that of MANUAL OP CATTLE-FEEDING. 475 the bye-fodder, is a narrow, or at least medium one (1 : 5 to 6). 9. If it is desired to test the correspondence of the calculated amount of digestible protein with that really present, the latter may also be calculated by Stohmann's formula, page 256- APPENDIX. Of the tables contained in the Appendix, I. and 11. are essentially those of Julius Kiihn {Mentzel ds v. Zengerke's Lomdw. Kalender, 1880), and HI. and IV. are from Wolff. As regards numerical accuracy, there is little difference between Kiihn's tables and WolfPs, the averages of the former being mostly identical with those of the latter. As will be seen, Kiihn's contain, in addition to the average composition and digestibility, the range of variation hither- to observed in these respects, and thus afford a better means of estimating the composition of particular feeding-stuffs. (Compare page 467, and also the remarks in the preface.) In Table I. Wolffs classification of 'meadow hay and clover hay has been introduced, and averages of all availa- ble analyses of American feeding-stuffs have been given. For the latter the author is indebted to the valuable com- pilation of Dr. E. H. Jenkins, published in the " Keport of the Connecticut Agricultural Experiment Station " for 1879. In Table II. Wolff's classification of ha;y has also been introduced, and likewise the results recently obtained by Wolff in experiments on the horse {Lamdw. JahrbiicJi- er, YII., Supplement *!.). In regard to the manner of using the tables, compare Chapter VII., of Part III. In all the tables " protein " signifies nitrogen x 6.25 ; that is, it includes gelatin, amides, ajid all other forms of non-protein. 478 MANUAL OF CATTLE-FEEDING. 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Q0t*O'^00O00t"iHe0 t* e- 00 O flO CO W OS t^; O t" O* lO EH 9 « I aSviaAy o; to i-j « M a t*. o p»_ r*^ o ") o i-I i-i tA ca i-i ot iH H o* "** 'aSBJdAy •raix-eji ^eo : : :nrA :« : S (COS ■ • -t-.W ;0 ; o H ■* «5 rH 00 O 00 M n M oi o oi oi oo' oi w oo' g O 13.8 17.9 10.1 IB.B 10.9 ao.d CO •raiuiji ido't^ -id CO -co •aSBMAy oooooooooo •raixBH f^ CO r-i lo iH Ot n « c4 iH ot- is . t-; OS lO X t; s-;; JS .rHWCOlOOO t^wotoooiwooor*'**!'^ «o © mt> m "O «' © 00 «) D-* d 81.7 82.4 68.2 72.4 ■00Ot--*»D coos 00 lO •rH is •OrH'0001^_tH«5C«MOO «' oo' en CQ «3 ^* 00 rA d oo* c* iHooit^n«oan«co^'* tOfOt • 'OOOS •raiuTjv; t^do) • 'dt^ Sis 03 CO 0DO3 t- t- 'H dcd^i-4 00 OS 00 CO 00 • B I? 00 i55 "^oocoo-^ COCOCDi-fC 52 1^ r-' oj 1 QOQOt-OOO VB(k' i' MANUAL OF CATTLE-FEEDING. 483 H « V> Ot O -^^ <« b>, a 00 Ol ►; ^> rH Ot O iH U) n O Ok •« f-l Ot O 00 n Ol t>> o -^ ^ rt ° S ***** ^' rt H '*'**« "^ rt S * '^' ^' " '^ ***' ^ ** °* "* ° ^ '^' *** OiOM CQ H n 00 d s eg . :^«ost-«3t^TOio jg«*^ \ j^w :oi«= : I : id ,-; id t-C so CO 03 w : :»cd»H03'cdr;jcd>rf :«So3»d : :nc»>o<0'^noitoac4t-cqo((nc<]ooo' 00 <-((-( ^'ofo *0 oo' CO S i ^Smm ;iss ; ;Sg ii i igsssss id w T< GO TO CO i i :Si33|353 :g§s j iss ;|§ : :5S3355 00* CD 0" CO moonioioioiooocgc4or-c<4i«i-t --^hhio eo'VdrVrHcocQM'd'OrtjHVw^mMoigjjHcqVrHri :po'dc> oicgc^ to* d d d 03 5 ; ;5SSSSSS2 isss ;5§^ :ss : iS ;s : : i iH -CO t- :d 00" ec O § ; ;S22S5553 ;5S| iSH 133 j j^ S ; i j to o5 q aS-3g|SS^SSSS^S5S|SSSSSS55SS3S OOlOO ddca (0 "O* CO H rH CO lo ; ;« oi 1-1 iH'V so oiq ;!DiO'^ 1-1 1-t • •T-ioie4G«ot' 3^3 a £"3 ■sig ,e aS bans 1 o S - g 1 *. S « 5 •■p-'S'K- ,.-■28 Egg SBy> j3£ a ■W -w 43 l« 2 C to «.* «is;s ii^t! 5 ■03 484 MAISTTJAL OF CATTLE-FEEDING. t^ t^ 00 iS tr^ tA i:^ IP ^-^ 16 tt? id to t^ to ei(d •s3-ei9Ay « .0 . /*r^ r-i :t«^ : ;iH» o ^ t^ 00 00 « ot '<; 00 r* eq t> ^ a >o « o 10 iH m 01 00 00 1-i d c^ GO* iH Vc4 10 m 10 to ^' 00 iHH i-( « fH iH « rH CT C9 •raiXBH ■^ CO 00 1- 00 00 OS t- :t-THO«« •raiuijt coTHrHioc^oooo* ;i^iqi-joocq '93V33A.Y 1^ mo viotiooot mi-icoiH^aeioot* ^t* cj o C4cOCqrOCO«C4n^^COC4C4C4C>]^ loco '00 ;os ■ :'9'-VO:«eO 'eSuaAy OC4C40COOIO «caM"«ococoi-t loooconnt^oooncaotuxoto^oioo oooo«o«oqoMco .;o^t-«<»^- ; ;eo»-j *M Tlf-I I-lrHS* •- «lH 1-1 - • 1-1 ■93VJ9A.Y t^ot^r*«ow i-fM'«t«i«O00Oj i-liHiHi-liH ViHio^t*>Oteqot*o«ou9omc9i-(^e^o 00 to o 10 00 00 In ot OOOlOOOtOOOOCOCOOtOOOtOlOtCOCOooCOCO s^ ■■& cdeowT-IoiowiM •co-^oioio • 'COO CO iq »-i a* -"Ji t- o so ;o>cao. :-a :•§? II ^^S. ^.g S w' J'. Htfi 9H4 n S : o MANUAL OF OATTLE-FEEDING. 486 00 CO ceo a3»e4 0«uat^9«t:-9couoeoerii>oi-*oiiHC^'^eo'*oio*o^ncoio^^ 0« «SQ»W t-iO«C!0 • >T CO W L- ■«J' so t- -^ •T-trH ■« :S| jSnSS . S com rHCO woo-* b* PI COM iHiH do c9 : « : • -coc- Ofr*CCCO. odOTOW 2.5 0.23 0.9 1.2 T.110 o'ra 1.1 '6.23 0.1 0.25 0.8 ^ : 1-* ; *0 C^*0iQt»*O001OHt^iHc0^eQ0tl0niHf-I^OlOOl00 OOM •6 m CO d N © ■** ^ « ^' *' ^ ID* rH T-T r-" d « id oi ■*' « ^" >o « co* i-I rH «* d th d t*^ • -COOq rr>CCG>tO (NrHrHOO • CO CO iH « US U3 O -^^ 'raO •ia33i-tO -O iHOI (Oip ^ •ST T-IC4 i-tiHi-iiH .i-tT-tiHri tH PO . . . Ti i-( • :S^ lOlOeOiH T-JOOrHffl •COfc-^i-HCOOOOOt- rHTO«d dcod« loJoT-ioocodoocd ■ O&fr- .{wQooO t»cooo oc3iHo to•oo^>t«coooto(oot>ocoHcocoe^n^oo ooi o^^ e-'c«.'dd co'oc^t^ dd^•'ddt«'t«*ddOlC3ciata}c4codt<•*^^o^oiotlXl "OH dr4 piMOiot ovooooco 00 oo CO 00 oi oo 00 ot ot 00 u3 Ok CO CO C3 M ot ca c« « iq -^ cod^oi 03 00 GO 93 laoiOb- 'O3t-e0O oooo :oco :«fwo '00 coo ■oot- t-OOIO t-^=>CDiH ;^10003CO COOtaOJO 'QOI^SaDCO IXQOCOCD .-^ COA lOlO d CO rj d ill . • o ' : ft : :a • » ■' s, • a <9r S « ti ■ S'l ar a « a . 1=1 !1|l"^-§ • 1^-1' a«||i-1 »u> 486 MANUAL OF CATTLE-FEEDINGf. •aSvjaAY •rajuijT ■9BVJ3A.Y 9 H ■raixBjf 09 00* o ^' ^ to ^' ■** »o «' «o «>■ * • •« 'aS'BjaAY ■unxBji » hI I •aSBiaAy 1^ 'a3BJ3AV •mixBTf o" o o o o erf ^ o di rA o «' i-i oo* « o C9 rH . Ol Ot lOOOOlM t^UliHOOOOOOO O 00 Ot OltOOO WOaOl NiO^O CJOtH :§ am rn 1 F- ■a V. Q. y. A W H fa "5 1 ^ I 1 s d n n o U ■g c t; :^ 5 e S. a o II MANUAL OF CATTLE-FEEDING. 487 488 MANtTAIi OF CATTLE-FEEDING- •aSvjaxy •mpcBTj/z •miuiH 'S^BiSAY •xnixBH O M 'm|aiH 'sSiuaAY 'onxBjg; •I a « (> 10 i-H od ^" aJ t- W t- t- « t- lO ui ^ OS 3d OS Tr< ■* CO w t- Tji CQ ^ 5D «p -^ CO • • ■ ^ CO i6 -«< 'S o CO • • • Q0Q0OOOO<--« OWOOOt-iO l-EDOOO-*CO SiS 10Tt<00000 (>• "r-lOlO 'aSvJaAY •inixBH 'mmiif OQOOOOOCO i-I od OS erf t-' 00 CO t- CO t- CO «5 ■© C- OStHOOOOO "ill! Ill 1 - i a :;3 1 rHOCOOli-t CO CO CO rJ t-: 00COCO1O4O ooooooos i£)U30COCO a MANUAL OF OATTLE-FEEDING. 489 CQ •OOO WOWW ; CO O 00 O 00 '* • a«-*c Wt-r-OS lO OS'^COt- O05C-iM (MOOO OMCDt- QoS io ;coico :o :o cDOJoaio o^oco C- '©iTtHi-l t-lOODGO OCOCOCD CO ■aSwjaAy Tt TjiOSOS-* OOTOirt •UIIUTH t- ;coosio ;(Dt-THiO oi • •*■ CO i> • o CO rr iri i- 't-cot- '000150009 COWCTO 0t--*0> S CI o o SB . (U (fl r1 ca oja S o S, « HI O boH* CI- s - » l-S ■sg.§ .-NO) O'r !* S a S -a-? M -^13 Sag ^3- «■ on S « J A ^ 43 (U m- - =3 S Cf -P MANUAL OF CATTLE-FEEDING. 491 ^ ggillg oi- ■•:;:; : g^ : i : : : : : cot- _- C0Z>SSU3Qp»OO comwaooa^ooi>o cufft • • : :o» (Q P BO •^ rt ■ * g ^ S GO H la h O - r^ -° ESS 5 SiZ aQffinSoQizi Pin 492 MANUAL OF CATTLE-FEEDBI!r0. 0- Table IIL— FEEDING STANDARDS. A. — Per Day and Per 1,000 Lbs. Livb-weight. NtTTBITITB (DlGEBTI- BLE) SUBSTANOEB. 1 (0 k V s §1 1 1 s 1 1 1. Oxen at rest in stall. . . . 2. Wool sheep, coaiser breede. ** ** finer breeds, 8. Oxen moderately worked ' ' heavily worked .... 4. Horses moderately worked. '■ heavily worked. 5. Milk cows 6. Fattening oxen, 1 st period "2d " " 3d 7. Fattening sheep, 1st period " 2d " 8. Fattening swine, 1st period ' " 3d " " " 3d " 9. Growing cattle : Age, Avegjage live-weight, montllB. per head. 2-3 .... 1.5aibB.* 3-6 .... 300 " 6-13 .... 500 " 12-18 ,.., 700 " 18-24 ,,,, 850 " Growing sbeep : .5-6 ,,,, .561bs,* 6-8 ,,,, 67 " 8-11 ,.,, 75 " 11-15 ,,,, 83 " 15-30 ,... 85 " 11. Growing fat pigs : 2-3 .... 50 lbs.* 3-5 .... 100 " 5-6 .... 125 " 6-8 .... 170 " 8-12 ,,,, 250 " 10. Lbs. 17.5 30.0 33.5 24.0 I 26.0 32.5 25.5 24.0 27.0 26.0 25.0 36.0 35.0 36.0 31.0 23.5 23.0 33.4 34.0 24.0 24.0 28.0 25 33.0 23.5 23.0 43.0 34.0 31.5 27.0 31.0 Lbs. 0.7 1.3 1.5 1.6 3.4 1.8 2.8 25 25 3.0 3.7 3.0 3.5 5.0 4.0 3.7 4.0 3.3 2.5 2.0 1.6 3.3 27 2.1 1.7 1.4 7.5 5.0 4.3 3.4 3.5 Lbs. 8.0 10.3 11.4 11.3 13.3 11.3 13.4 18.5 15.0 14.8 14.8 15.8 14.4 Lbs. 0.15 0.20 0.85 0.30 0.50 0.60 80 0.40 0.50 0.70 0.60 0.50 0.60 27.5 24.0 17.5 13.8 13.5 13.5 13.0 12.0 15.6 13 3 11.4 10.9 10.4 3.0 1.0 0.6 0.4 0.3 0.8 0.6 0.5 0.4 0.3 30.0 35.0 33.7 30.4 16.2 Lbs. 8.85 11.70 13.15 13.20 16.10 13.60 17.00 15.40- 18.00 18.50 18.10 18.70 18.50 33.50 3800 20.20 19.8 17.7 16.6 1,5.4 13.9 19.6 16.6 14.0 13.0 13.1 37.5 80.0 38.0 33.8 18.7 1 : 13.0 9.0 80 7.5 6.0 7.0 5.5 5.4 65 5.5 60 5.5 4.5 5.5 6.0 6.5 ;4.7 ;.5.0 ;6.0 ;7.0 ;8.0 :5.5 ;5.5 ;6.0 :7.0 :8.0 ;4.0 :5.0 :.5.5 :6.0 :6.5 * See note on opposite page. MANUAL OP OATTLE-FEEDING. 493 Tablb III. — Continued. B. — Peb Day and Feb Head. NUTBITITE (DlQESII- .2 BI.E) BUBSIAHCEB. •i >• 1 1 1 • o- t 1 1 Growing cattle : Lbs. Lbs. Lbs. Lbs. Lbs. Age, Average live-weight, months. pet head. 2-3 .... ISOlbs.* 3.3 0.6 2.1 0.30 3.00 4.7 3-6 .... 300 " 7.0 1.0 4.1 0.30 5.40 .5.0 6-12 .... 500 " 13.0 1.3 6.S 0.30 8.40 6.0 13-18 .... 700 " 16.8 1.4 9.1 0.38 10.78 7.0 18-24 .... 850 " 20.4 1.4 10.3 0.36 11.96 8.0 Glowing sheep : 5-6 .... 56 lbs.* 1.6 0.18 0.S7 0.045 1.095 .5.5 6-8 .... 67 " ...... 1.7 0.17 0.85 0.040 1.060 .5.5 8-11 .... 75 " 1.7 0.16 0.85 0.037 1.047 6.0 11-15 .... 83 " 1.8 0.14 0.89 0.033 1.063 7.0 15-20 .... 85 " 1.9 0.13 0.88 0.025 1.047 8.0 Growing fat swine : 3-3 .... 501bB.* 21 0.38 1.50 1.88 1:4.0 3-5 .... 100 " 3.4 0.50 3.i50 3.00 5.0 5-6 .... 135 " 3.9 0.54 296 3.50 5.5 6-8 .... 170 " 4.6 0.58 3.47 4.05 6.0 8-13 .... 250 " 5.3 0.63 4.05 4.67 6.5 t • The GfCmian pound is eqttal to 1 Vio I^- avoirdupois. The above weights are therefore to be increased ^/lo to represent our weights. For practical purposes, however, this reduction will be in most cases unnecessary, as the weights are but relative and approxi- mate. The quantities of nutrients calculated per 1,000 pounds live-we^ht, of course, need no reduction, being simply relative, and the Game is true to a certain extent of the quantities per head. 494 MANUAL OF CATTLE-FEEDING. •^^J •P9J-113A\ ■^9} ifWA 'XTBd^ •JIB3 ;«J •?B^ •»BJ Jl«H •paj-IPAi. •Tttcoosb* 'Me-wio w* i oco pCJCO CD COCQ, CTH>HOO'rHi-icd t-^O ■gOW (M OCO 04 C0OC0OTi-jOl>Q0 OOCO ■^oeo o coo i> ■<*)fficpM(Mcoosas t*»-ir-icJocii(?i- -^ CD rH* 00 CO ©» CD ■* CO « Tji •«*< oco ■4 oosoco u 01 CO CD* r-i Ph .cD^^mcDcolOl^^^-^»o co'** :C«iC)dc>rHddc^r4Tli CiiH \ ■gOdTHt- . .l>CD10t-CO»0950>COS I>;t-( ^, irf tH t^ »H * ! oi o' o' o' 1-5 d CO T-i oi w w' £ 00 -(ji 06 »-i 0) r-t 1^ on 1^ 00 CO Tti t- 10 iC « iO-O CO '^ r-( 1 CO s i*^ bo §1 I'D ■ >3 01 o .S'S h S -«3 on . J CI cS ID n d ^ 0) B a g o :^ S ° n"" ^ ^ o o CO 00 » MANUAL OF CATTLE-FEEDING. 495 .00U3O Q0»-itHO t-OOt-O tf irf OJ CO W* OWiTJtPO O»0C-?DQ0 widodoi-Tjl fftiHOOO OCOiOCd'* OCOOSiAOa OtHOOM ,-^co CO go irico MOO t>co 00-* coco oo odcd o2 :1 H-5 ■III! jaj i ^M S CO r-^O Tli T-lrH W C0Oi-H«5 t-: i> o' -*' of ;>; o m B o S^ • h5 ^ ■s 3-9 'S ojq,cq CO COOT 00* CO CO C3C0CO CO ^ CO odioco iHCOiO cot- OS cdcoco r-IOOOO 496 MANUAL OF OATTLE-FEEDIITG. •»»J ■psj-IPA •JBJ &I3\ ■1BJJI«H ■pai-naA I 6 n •J[TO *«4 S CO rH P< S lOiH S to «OOSO> ■*03^C0 rH iCOOtO o o' o o o > o* iHiHOOO O i-iO ^ r-iO « rH T-i O CJ O O O hOOT i-H rH O CS O C> O iH i-i O O" O O O iH iH O O O' O O r-i--00000 i-itHOOOOO "VSd 3 (DO •p9Jiiaj\ 00 Oi 1X5 to a _■ q OS K -ij a Q a •>( H o