ibtatt College of Sericulture ^t Cornell iMnthcrsttp atljata, iS. g. Hibrarp THE PENNSYLVANIA STATE COLLEGE AGRICULTURAL EXPERIMENT STATION. e Computation of Rations for Farm Animals* STATE COLLEGE, PENNA. 1898. Cornell University Library The original of tiiis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924003032632 THE PENNSYLVANIA STATE COLLEGE Agricultural Experiment Station. The Computation of Rations for Farm Animals. BULLETIN OF INFORMATION No. 1. CoritritDtited. by the School of Agrictalttare. THIRD EDITION. STATE COLLEGE, CENTRE COUNTY, PA. FEBRUARY, 1898. CS THE PENNSYLVANIA STATE COLLEGE Agricultural Experiment Station. ADVISORY COMMITTEE OF BOARD OF TRUSTEES. THE HON. JOHN A. WOODWARD, Chairman Howard. JOEL A. HERR, Esq Cedar Springs. THE HON. AMOS H. MYLIN Lancaster. SAMUEL R. DOWNING, Esq Goshenville. GEO. W. ATHERTON, LL.D., President of the College . . . State College. H. P. ARMSBY, Ph.D., Secretary of the Committee. OFFICERS AND ASSISTANTS. THE PRESIDENT OF THE COLLEGE. HENRY PRENTISS ARMSBY, Ph.D Director. WILLIAM FREAR, Ph.D Vice-Director and Chemist. WILLIAM A. BUCKHOUT, M.S ' . . Botanist. GEORGE C. BUTZ, M.S Horticulturist GEORGE C. WATSON, M.S Agriculturist. WILLIAM C. PATTERSON Superintendent of Farm. MISS JULIA C. GRAY Secretary.' WILLIAM S. SWEETSER, B.S \ J. AUGUST FRIES [ Assistant Chemists. MILTON E. McDonnell, m.s ) HARRY HAYWARD, B.S Assistant in Dairy Husbandry. ENOS H. HESS Assistant to the Directo^ CHARLES ALBERT BROWNE, Jr., M.A '■ ) , . , CASSIUS W. NORRIS | Assistant Chemist^ MISS MINNIE EDITH GRAY Stenographe:] TelegraphandPostOffi.ee, ) State College, Centre County, Pa. Railroad and Express Station, J ■■ Telephone 14 2-4, Bellefonte Exchange. ^g- The bulletins and reports of the Station will be mailed regularly, free 01 charge, to all residents of the State who request it, so far as the supply will permit, Address, Director of Experiment Station, State College, Centre County, Pa. Visitors will be welcomed at all times and given every opportunity to inspect the Station in all its departments. SCHOOL OF AGRICULTURE. FACULTY. GEORGE W. ATHERTON, LL.D., President. HENRY PRENTISS ARMSBY, Ph.D., Dean, Lecturer on Stock Feeding. WILLIAM A. BUCKHOUT, M.S., Professor of Botany and Horticulture. WILLIAM FREAR, Ph.D., Professor of Agricultural Chemistry, GEORGE C. WATSON, B.S., M.S., Professor of Agriculture, GEORGE C. BUTZ, M.S., Assistant Professor of I/orticulture. LEONARD PEARSON, B.S., V.M.D., Special Lecturer on Veterinary Science, HARRY HAYWARD, B.S., Instructor in Dairy Husbandry. J. AUGUST FRIES, Assistant in Agricultural Chemistry . MILTON E. McDonnell, m.s., Assistant in Bacteriology, ENOS H. HESS, Assistant in Stock Feeding, C, p. VAN DYKE, A ssistant in Butter-making. F. F. PEPPER, Assistant in Butter-making, E. L. ADERHOLD, Assistant in Cheese-making. OTHER INSTRUCTORS. I. THORNTON OSMOND, M.S., M.A., Professor of Physics. LOUIS E. REBER, M.S., Professor of Mechanics and Mechanical Engineering. GEORGE GILBERT POND, M.A., Ph.D., Professor of Chemistry. HENRY T. FERNALD, M.S., Ph.D.,~ Professor of ZoSlogy. FRED E. FOSS, B.S., M.A., Professor of Civil Engineering, JOSEPH M. WILLARD, B.A., Professor of Mathematics, FRED LEWIS PATTEE, M.A., Professor of English and Rhetoric, LAWRENCE M. COLFELT, D.D., Preacher to the College; Professor of Ethics. THOMAS C. HOPKINS, M.S., M.A., Assistant Professor of Geology. CARL D. FEHR, M.A., Assistant Professor of German. SILVANUS B. NEWTON, A.B., M.D., Director of Physical Education. ANNA E. REDIFER, Instructor in Industrial A rt and Design. IRVING L. FOSTER, M.A., Instructor in the Romance Languages, THE PENNSYLVANIA STATE COLLEGE. School of Agriculture. THE COMPUTATION OF RATIONS FOR FARM ANIMALS. BY HENRY PRENTISS ARMSBY. INTRODUCTION. THE investigations made by the Agricultural Experiment Stations of this and other countries during the last forty-five years have resulted in the accumulation of a large amount of valuable infor- mation regarding the scientific principles of stock feeding. Thanks to these investigations, it is now possible for the feeder, by consulting tables showing the composition and "digestibility of feeding-stuffs and by making comparatively simple calculations, to adapt his rations with a considerable degree of accuracy to the purpose he has in view. Such tables have been frequently published, but experience shows that, in most cases, even the more intelligent farmers do not find it easy to put them to practical use. The truth of this statement is shown not only by the correspondence which comes to the Station, but very strikingly by the numerous letters received by agricultural papers asking to have rations computed. Answers to inquiries of this sort have come to be a prominent feature in many such papers and are doubtless helpful to the inquirers. At the same time it is plain that on many accounts it would be far better for the farmer to make these computations for himself if possible, since he best knows the conditions which surround him, and is thus best fitted to adapt his rations to his conditions. It is hoped that this publication will prove helpful to those who desire to compute rations for themselves. It does not purport to con- tain any information that has not been frequently published before, but consists simply of a brief outline of the general principles on which the computation of rations depends, followed by somewhat detailed illustra- tions of the method of solving some of the more important problems that arise in practice. 5 6 THE PENNSYLVANIA STATE COLLEGE. PART I. GENERAL PRINCIPLES, COMPOSITION OF ANIMALS. The very large number of different substances found in the animal body may for our present purpose be grouped under four heads. 1. Water. This is one of the principal ingredients of the animal body, amounting to from forty to sixty per cent, of the weight of the live animal. 2. Ash, or Mineral Matters. These amount to from two to five per cent, of the weight of the live animal. Their presence is most evident in the bones, but they exist also in small proportion in all parts of the body and are just as essential as any of the other ingredients. 3. Protein. A name given to an important group of substances of which washed lean meat or the white of egg may be taken as the type. They all contain about sixteen per cent, of the element nitrogen, which is entirely lacking in the three other groups, and are remarkably siniilar in their general properties. The organic part of the bones, the ligaments and muscles which bind together and move the bones, the skin, the internal organs, the brain and nerves, — in short, all the working machinery of the body, — are composed very largely of protein. Con- sequently, this group of substances is of great importance, and a due supply of it in the food, particularly to growing animals, is indispensable. 4. Fat. This term needs no special explanation. The proportion of fat in the body varies greatly, but seldom falls below six or rises above thirty per cent. The average composition of different animals in various stages of fattening is given in Table I. of the Appendix (page 31). COMPOSITION OF FEEDING-STUFFS. In the various feeding-stuffs which serve to build up and maintain the animal body, we find the same four groups of ingredients which we do in the body of the animal, namely, water, ash, protein, and fat. The individual substances which make up these groups differ more or less from those found in the body of the animal, but for our present purpose these differences may be regarded as of comparatively little importance. In addition to these four groups, feeding-stuffs contain another group of substances, not found to any considerable extent in the body of the animal. This group is known as carbhydrates. The most familiar sub- COMPUTATION OF RATIONS FOR FARM ANIMALS. 7 stances belonging to this group are starch, the various kinds of sugar, and woody fibre. Starch being the most abundant of these in most foods, this class of substances is sometimes spoken of as starchy substances, but the technical name, " carbhydrates," is on the whole more accurate and expressive. The following tabular statement may help to fix in the mind the state- ments which have just been made regarding the composition of animals and feeding-stuffs : Ingredients of Animals. Ingredients of Feeding-Stuffs. 1. Water. i. Water. 2. Ash. 2. Ash. 3. Protein. 3. Protein. 4. Fat. 4. Fat. 5. Carbhydrates. Table II. (pages 32 and 33) of the Appendix shows the average com- position of a considerable number of American feeding-stuffs. In this table the common practice has been followed of dividing the group of carbhydrates into two portions. The " crude fibre" or " woody fibre" is stated separately, partly because it is thought to be of somewhat inferior nutritive value, and partly because it gives some indication of the bulki- ness and woodiness of the feeding-stuff. The column headed " nitrogen free extract" includes all the carbhydrates except the crude fibre. DIGESTIBLE MATTERS IN FEEDING-STUFFS. It is plain that the value of any feeding-stuff will not depend simply upon the total amounts of these various ingredients which it contains, but also upon the- proportion of them which the animal is able to digest and assimilate. In Table III. (pages 34 and 35) of the Appendix are given the percentages of digestible matter contained in the same list of feeding-stuffs which is given in Table II. The figures of Table III., con- sequently, indicate with a considerable degree of accuracy the relative values of the different feeding-stuffs, since they show to the best of our present knowledge the amount of real food which each one contains. Table III. also shows, in the first column, the percentage of total dry matter in each feeding-stuff By dry matter is meant all of the feeding- stuff except water. Thus, the first feeding-stuff given in the table is stated to contain 20.3 per cent, of dry matter. This means that in every 100 pounds of this feeding-stuff there are 100 — 20.3 = 79.7 pounds of water and 20.3 pounds of solid matter. In other words, the percentage of water given in Table II. and the percentage of dry matter given in Table III., when added together, equal 100. 8 THE PENNSYLVANIA STATE COLLEGE. The digestible carbhydrates and fats have been added together in Table III. because they serve substantially the same purposes in nutrition, as explained in the next paragraph, and it therefore simplifies calculation to unite them. USES OF INGREDIENTS OF FEEDING-STUFFS. Having learned the amounts and proportions of digestible matters present in different feeding-stuffs, we next ask, what use does the animal make of these different substances ? Water we may leave out of account, because we do not use feeding- stuffs for the sake of the water which they contain. Ash. The ash, or mineral matter, of feeding-stuffs serves as a source of supply for the mineral ingredients of the body. Under ordinary cir- cumstances the supply of ash in feeding-stuffs is amply sufficient for the needs of the body, and we need not concern ourselves regarding it. Occasionally, especially in feeding young animals or in cases where the ration consists very largely of grain, it is desirable to add precipitated chalk, wood ashes, or precipitated phosphate of lime to the ration. Protein. The protein of the food is used to build up and keep in repair the working tissues of the body, which, as we have seen, consist very largely of protein. In other words, we may say that protein supplies material for the growth of tissue. This growth of tissue may be an actual increase in bulk, as in the case of the growing animal ; it may be simply the making good of waste, as in the mature animal ; it may be the growth of wool or hair ; or, finally, it may take the form of the production of milk, this being in reality the growth and breaking down of tissue in the udder. For all these purposes protein is indispen- sable, and its place cannot be taken by either carbhydrates or fat. If, however, more protein is given the animal than it needs for these various forms of tissue growth, the excess is burned up, like fat and carbhydrates, as explained below, or perhaps furnishes material for the production of fat. Fat and Carbhydrates. The uses of these two classes of substance are so similar that they may be conveniently considered together. They serve three purposes. First, they are burned to produce the heat req,uired to keep the animal warm. Second, they are burned to produce the force exerted in the motions of the animal, somewhat as coal is burned under the boiler of a locomotive. Third, if the supply of them is greater than is needed for the production of heat and force, the excess gives rise to the production and laying up of fat in the body. It is on account of this similarity in their uses that the digestible carbhydrates and fat have been united in Table III. COMPUTA TION OF RA TIONS FOR FARM ANIMALS. g But while fat and carbhydrates have substantially the same uses in the body, a given weight of fat is worth more for this purpose than the same weight of carbhydrates. One pound of fat when burned will pro- duce, in round numbers, 2j^ times as much heat as a pound of carbhy- drates; consequently, fat is 2j^ times as valuable as carbydrates for fuel in the animal body. The same relation holds between the two as force producers, and probably as fat producers. For this reason, the digestible fat of the several feeding-stuffs of Table III. has been multiplied by 25^ before adding it to the carbhy- drates. In other words, the column headed " carbhydrates and fat" really shows the number of pounds of carbhydrates which are equiva- lent to the fat plus carbhydrates actually present, NUTRITIVE RATIO. We have just seen that the protein of the food serves, in the main, a different purpose in the animal economy from carbhydrates and fat. The relative amounts of these in a given feeding-stuff are therefore important. This relation is expressed by what is called the " nutritive ratio," which means the ratio of digestible protein to digestible carbhy- drates plus fat. Before making this comparison, however, we must, as just explained, multiply the fat by 2^, since a pound of fat is 234^ times as valuable as a pound of carbhydrates. This multiplication having been already made in Table III. (page 34), the nutritive ratio of any feeding-stuff in that table may be found by comparing the digestible protein with the digestible carbhydrates and fat. Thus, in the case of the first feeding-stuff, the ratio is i.i : 12.7. For greater convenience in comparing one feeding-stuff with another, however, the first term of the ratio is usually taken as unity. We have, therefore, the following proportion : I.I : 12.7:: I : II. 5. The nutritive ratio is 1:11.5; that is, there are 1 1.5 pounds of digest- ible carbhydrates and fat present for every pound of digestible protein. Nutritive ratios are spoken of as being " wide" or " narrow." A feeding-stuff with a wide nutritive ratio is one which contains a large proportion of carbhydrates and fat as compared with protein. A feed- ing-stuff with a narrow nutritive ratio is one which contains a small proportion of carbhydrates and fat as compared with protein. Thus, comparing the example just given with the nutritive ratio of cotton-seed meal, namely, i : 1.2, we should say that the soiling corn had a wide ratio and the cotton-seed meal a narrow ratio. Of course, the terms are relative. A ratio of i : 5 is a narrow ratio as compared with a ratio of 1:12, but is at the same time a wide ratio as compared with the ratio of 1:2. 2 lO THE PENNSYLVANIA STATE COLLEGE. PROPORTION OF PROTEIN NEEDED FOR DIFFERENT PURPOSES. What has been said regarding the uses of the ingredients of feeding- stuffs makes it plain that the proportion of protein in the food (that is, the nutritive ratio) should vary according to the purpose of the feeding. If tissue is to be built up or repaired, that is, if we are feeding for growth or for milk production, we need sufficient protein to furnish the raw material for this production. If, on the other hand, we are feeding for the production of fat or of work, we simply need enough protein to keep the animal tissues in repair, while the remainder of the food may consist of carbhydrates and fat. We may therefore divide the purposes for which farm animals are fed into two groups, as follows : Requiring more Protein. Requiring less Protein. Growth. Maintenance. Milk production. Fattening. (Wool production.) Work. Feed for work is classified above as one of those purposes requiring less, rather than more, protein in the ration, it having been conclusively shown that the carbhydrates and fat of the food are practically the materials which furnish the force exerted by the working animal. At the same time, a working animal must have a well-developed muscular system, and this in turn requires a reasonable amount of protein for its support, so that the feeding of working animals in reality occupies an intermediate position between the two groups given above. FEEDING STANDARDS. The statement just made, however, is not sufficiently definite for the purposes of the stock feeder. He not only needs to know that for some purposes he must supply more protein than for others, but he must know also what proportion of protein to carbhydrates and fat (that is, what nutritive ratio) is best adapted for the purpose he has in view, and he must know also how much food he should give. It is not yet possible to give an answer to these questions which will apply to every case. The proper ration will vary with the kind and quality of the animals fed and with the conditions under which they are fed, including financial conditions. There is no " best" ration for. fattening or for milk production, any more than there is a " best" plow or a " best" plan for a barn. In order, however, to supply a general guide, various investigators have condensed the results of experiments and of practical experience into what are called " feeding standards." Such a standard attempts to COMPUTATION OF RATIONS FOR FARM ANIMALS. n state what is, in general, and under average conditions, a good ration for the purpose in view. It shows what has given good results with other feeders, but it is not asserted that it is exactly adapted to the particular circumstances of each user. In other words, it is not a recipe, but a statement of experience. Furthermore, in order not to limit the user to a few specific feeding- stuffs, the standard is expressed, not in pounds of grain and fodder, but in pounds of dry matter and of digestible protein, carbhydrates, and fat. Thus, for a dairy cow weighing one thousand pounds, the standard recommended by one investigator is as follows : Dry matter 24.51 lbs. Digestible protein 2.15 " Digestible carbhydrates and fat 14'94 " Total digestible matter 17-09 " Nutritive ratio 1 : 6.9 This means that any combination of suitable feeding-stuffs containing these amounts of dry matter and of digestible matters will be as good a ration as the average of the rations from which the standard was obtained, and will therefore correspond in essentials to the experience and practice of good dairymen. It does not mean that every dairy cow ought to be fed exactly such a ration as this, or that if she is the best results will be obtained. It is simply, as has already been said, the condensed result of experience. In Table IV. of the Appendix (pages 36 and 37) are contained a num- ber of feeding standards for various purposes, most of them based upon the writings of German authorities. It is not proposed at this time to enter into the question of the suf- ficiency of these standards for the various purposes of feeding, or how they should be varied to suit different conditions. The consideration of these questions would involve an elaborate discussion of the whole science of feeding and would require a volume for its proper treatment. The purpose of the present publication is simply, as already stated, to help farmers to use the feeding standards we already have. In regard to the standards given in the table for fattening cattle and sheep, however, it should be said that these standards were propounded at a time when protein was supposed to have a more intimate relation to the production of fat than is now believed to be the case. Both practical experience and direct experiments unite to show that under American conditions entirely satisfactory results may be attained with feeding standards having a much wider nutritive ratio than that recommended in 12 THE PENNSYLVANIA STATE COLLEGE. Table IV. At the same time, these results have not yet been brought together in such a way as to permit a feeding standard to be deduced from them, like the one for dairy cows given above. The writer believes, however, that a nutritive ratio of i : 8 or i : 9 will be found quite as satis- factory for feeding fairly mature cattle or sheep as the narrower ration given in the table. The standards given in the table are for animals weighing one thousand pounds. For heavier or lighter animals it is usual to increase or dimin- ish the computed ration in proportion to the weight, although in practice the individuality of the animal will usually be a more important factor than the live weight. USE OF FEEDING STANDARDS. Granting that the experience of others, as expressed in a feeding standard, is worth following, we may avail ourselves of it with the aid of Table III. of the Appendix by the use of a little simple arithmetic. We have merely to devise a mixture out of the feeding-stuffs available which shall contain the amounts and proportions of digestible matter given in the standard, and which shall have a suitable bulk, as indicated by the amount of dry matter contained in it. When using such a mixture we shall know that we are following the general experience of good feeders. We shall not know that we are feeding the very best ration which could be used under our particular circumstances, but there is every probability that a ration computed in this manner will give much more satisfactory results than are obtained from the too common haphazard feeding based simply upon the feeding stuffs which happen to be at hand or upon the market price per ton. The following pages are intended to explain and illustrate by ex- amples the method to be followed in computing a ration corresponding to a given feeding standard, it being assumed that the standard itself is substantially correct. COMPUTATION OF RATIONS FOR FARM ANIMALS. 13 PART II. THE COMPUTATION OF RATIONS. In Part I. the general ideas upon which the use of feeding standards is based have been explained. We now proceed to take up the method of using these standards in practice. The general problem is to devise a mixture of suitable feeding-stuffs which shall correspond in the amounts of dry matter and of digestible matters which it contains to s'ome standard which has for one reason or another been fixed upon as suitable for the purpose in view. This is purely an arithmetical problem, requiring merely a knowledge of simple arithmetic, including percentage, and a little ingenuity. It is what the mathematician calls an " indeterminate" problem; that is, many mixtures of feeding-stuffs might be made, all of which would correspond to a given standard. Consequently it is impossible to give any rule for the computation of rations in the same sense in which we can give a rule for computing interest. The problem can only be solved by trial, and the method of doing it is best explained by examples such as those which follow, which are designed to illustrate the principal points likely to come up. The reader is urged to perform each of these examples for himself as the quickest and surest means of acquiring proficiency. COMPARISON OF A RATION WITH A STANDARD. Some fattening steers, averaging one thousand pounds live weight, are being fed, per day and head, 12 pounds mixed hay. 14 pounds corn chop (corn-and-cob meal). How does this ration compare with that recommended in Table IV. (p. 36) for the main fattening period ? In order to make this comparison, we need to compute the total amount of dry matter and the amounts of digestible matter contained in the ration. According to Table III. (p. 34) the foods used contain the following percentages of dry matter and digestible matter : . Dry matter. Digestible. Protein. Carbhydrates and fat. Total. Nutritive ratio. Mixed hav Per cent. 8S-7 84.9 Per cent. 4-7 4-4 Per cent. 42.7 66.5 Per cent. 47-4 70.9 I: 9.1 1:151 Corn-and-cob meal 14 THE PENNSYLVANIA STATE COLLEGE. Taking first the hay, we multiply twelve pounds by the percentages of the various ingredients to find the number of pounds of each of these ingredients contained in the twelve pounds of hay, as follows : Mixed Hay. 12 lbs. X .857 — 10.28 lbs. of dry matter. 12 lbs. X .047= 0.56 lbs. of digestible protein. 12 lbs. X .427 = 5.12 lbs. of digestible carbhydrates and fat. Taking next the corn chop, we perform the same operations, as follows : Corn-and-Cob Meal. 14 lbs. X .849 = 1 1.89 lbs. of dry matter. 14 lbs. X .044= 0.62 lbs. of digestible protein. 14 lbs. X .665 = 9.31 lbs. of digestible carbhydrates. Next, adding together the amounts of dry matter and digestible matter in the hay and the corn-and-cob meal, we have the total contained in the ration, which we may then compare with the standard : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. Nutritive ratio. Twelve pounds mixed hay .... Fourteen pounds corn-and-cob meal Lbs. 10.28 11.89 Lbs. 0.56 0.62 Lbs. 5-12 9-31 Lbs. 5-68 9-93 .... Total 22.17 1. 18 1443 15.61 I : 12.2 Standard 26.00 3-0 16.4 19.4 l: S.S This comparison shows us that our ration is considerably lower in total digestible matter than the standard, and that it is especially deficient in protein, the result being that its nutritive ratio is very wide as com- pared with that of the standard. As already explained, this does not prove that the ration is not a suitable one for the circumstances under which it is being used. It simply shows that it does not correspond with the experience and judgment of those who proposed this particular standard. IMPROVEMENT OF A rAtION. A bunch of yearling steers, averaging five hundred pounds each, are receiving per day and head : 20 lbs. corn silage. 4 lbs. oats. 2 lbs. clover hay. 2 lbs. corn meal. Is it desirable to make any change in the ration ? COMPUTATION OF RATIONS FOR FARM ANIMALS. IS According to Table III. (p. 34) the feeding-stuffs in use contain the following amounts of dry matter and digestible matter : Dry matter. Digestible. Protein. Carbliydrates and fat. Total. ratio. Corn silage Clover hay Per cent. 27.9 84.7 89.0 85.0 Per cent. I.I 6.4 9.2 S-S Per cent. 18.2 38.S S3-2 71.1 Per cent. 19-3 44-9 62.4 76.6 I : 16.5 I : 6.0 Oats Com meal l: 5.8 I : 12.9 Making for each feeding-stuff exactly the same calculations as were given in detail in the preceding paragraph, we have the following results as compared with the standard : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. ratio. Twenty pounds com silage .... Two pounds clover hay Four pounds oats . . . . \, . . . Two pounds corn meal Lbs. 5.58 1.69 3.S6 1.70 Lbs. 0.22 0.13 0.37 O.II Lbs. 3-64 0.77 2.13 1.42 Lbs. ■ 3-86 0.90 2.50 I-S3 Total I2S3 0.83 7.96 8.79 I :g.6 Standard 12.00 1-3 7-5 8.8 I : 6.0 We thus find that the total quantity of digestible matter which is being fed corresponds closely with the standard. The difference in the amount of dry matter is likewise immaterial. The amount of protein, however, is decidedly less than that recommended in the standard, and consequently the nutritive ratio is much wider. A reference to the com- position of the feeding-stuffs shows us that the clover hay and oats have about the nutritive ratio of the standard, while the silage and the corn meal have a much wider ratio. Evidently, if it is desired to retain the silage in the ration, it will be necessary to replace some of the grain by something much richer in protein than either the oats or the clover. Running over the last column of Table III. for such a feeding-stuff, that is, one with a narrow nutritive ratio, we find, among others, cotton-seed meal, having a very narrow ratio, the figures being as follows : i6 THE PENNSYLVANIA STATE COLLEGE. Dry matter. Digestible, Nutritive ratio. Protein. Carbhydrates and fat. Total. Cotton-seed meal Per cent. 91.8 Per cent. 37-2 Per cent. 437 Per cent. 80.9 I : 1,2 Replacing the two pounds of oats by the same amount of cotton-seed meal, we find that the ration stands as follows : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. ratio. Twenty pounds corn silage , Two pounds clover hay Two pounds oats Two pounds corn meal . . . Two pounds cotton-seed meal . , Lbs. S-58 1.69 1.78 1.70 1.84 Lbs. 0.22 0.13 0.18 O.I I 0.74 Lbs. 3-64 0.77 1.06 1.42 0.87 Lbs. 3-86 0.90 1.24 1-53 1.61 • ■ Total Standard 12.59 12.00 1.38 1-3 7.76 7-5 9.14 8.8 1:5.6 I : 6.0 It is now rather better than the standard, and while it will cost a trifle more than the first ration, there is little question that it will be much better adapted to growing. animals. COMPUTATION OF A RATION FROM GIVEN FEEDING-STUFFS. The following feeds are available for constructing a ration for dairy cows, to correspond with the so-called " Wisconsin" standard (p. 11) : Com forage Clover hay Com meal . Wheat bran Gluten feed Dry matter. Per cent. 57.8 84.7 85.0 88.1 91.7 Digestible. Protein. Per cent. 2.5 6.4 5-5 12.0 19.4 Carbhydrates and fat. 36.1 38.5 7I.I 45.4 '63.3 Total. Per cent, 38.6 44-9 76.6 57-4 82.7 Nutritive ratio. 14.4 6.0 12.9 3.8 3-3 COMPUTATION OF RATIONS FOR FARM ANIMALS. 17 The first step in the construction of a ration is to fix upon the amounts of coarse fodders. It is usually desirable to use as large a pro- portion of these as possible, since they are usually cheaper sources of food than grain. On the other hand, the amount of them which an animal can consume is limited. Much depends upon the individual animals, and the proper amount can only be told by trial. We need, according to the standard selected, a total of about 24.5 pounds of dry matter. Of this we should probably aim to get from fourteen to sixteen pounds in the form of coarse fodder. Corn forage being a cheap feeding- stuff, we shall naturally use this freely, with probably some hay for variety. By a little trial, we find that fourteen pounds of corn forage and eight pounds of clover hay will give us nearly fifteen pounds of dry matter and the amounts of digestible matter shown below : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. Nutritive ratio. Fourteen pounds corn forage . . . Eight pounds clover hay .... Lbs. 8.09 6.78 Lbs. 0.3s 0.51 Lbs. 5 -OS 3.08 Lbs. 3-59 14.87 0.86 8.13 8.99 1:9-5 To this we have to add sufficient grain to bring the ration up to the standard. The proper amount we must ascertain by trial. We will take at a venture six pounds of corn meal and three pounds of wheat bran. Adding this to the ration we have : Dry matter. Digestible. Protein. Carbhydrates and fat. Nutritive ratio. Fourteen pounds corn forage Eight pounds clover hay . Six pounds corn meal . . . Three pounds wheat bran . Lbs. 8.09 6.78 S.io 2.64 Lbs. 0-35 0.51 0-33 0.36 5.05 3.08 4.27 1.36 Lbs. S-40 359 4.60 1.72 22.61 i-SS 13.75 15-31 1:8.9 Comparing these figures with the standard, we find that the ration is somewhat deficient in quantity, and that its nutritive ratio is considerably too wide. In the list of feeding-stufifs available we see that the gluten i8 THE PENNSYLVANIA STATE COLLEGE. feed is the one containing the largest proportion of digestible protein, and, since our ration lacks protein, we naturally make trial of this. We need 1.79 pounds of total digestible matter to bring the ration up to the standard. This would be almost exactly supplied by two pounds of gluten feed. Adding this to the ration, it stands as in the following table : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. Nutritive ratio. Fourteen pounds corn forage . . . Eight pounds clover hay . Six pounds corn meal Three pounds wheat bran . Two pounds gluten feed . . . Lbs. 8.09 6.78 5.10 2.64 1.83 Lbs. 0-3S 0.51 0-33 0.36 0-39 Lbs. S-oS 3.08 4.27 1.36 1.27 Lbs. S.40 359 4.60 1.72 1.65 24.44 1.94 1503 16.96 1:7.7 We now have the total amount of digestible matter right, but the nutritive ratio is still too wide. Evidently we need to use less corn and more bran and gluten feed. Reducing the corn meal by two pounds, and adding one pound each of bran and gluten feed, we have the following : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. Nutritive ratio. Fourteen pounds corn forage Eight pounds clover hay . . . Four pounds corn meal Four pounds wheat bran .... Three pounds gluten feed . . Lbs. 8.09 6.78 340 352 2.75 Lbs. 0.3s 0.51 0.22 0.48 0.58 Lbs. 3.08 2.84 1.82 1.90 Lbs. 5-40 359 3.06 2.30 2.48 24.54 2.14 14.69 16.83 I : 6.9 The computed nutritive ratio now corresponds almost exactly with the standard. The total digestible matter is a trifle low, but the differ- ence is too small to be significant. By proceeding in this manner, with a little patience we can usually get a ration corresponding as closely as is necessary to the standard provided the feeds available admit of it. With a little experience one very soon learns to guess pretty closely, and with some practice finds COMPUTATION OF RATIONS FOR FARM ANIMALS. 19 the computations very easy. An exact agreement with the standard need not be sought for, since in practice the composition of the feeds will probably vary more or less from the average of the tables, while the amount which the animal will eat will probably also vary more or less from that computed for them. THE SELECTION OF FEEDING-STUFFS. In the selection of feeding-stuffs, one of the most frequent and im- portant questions which arises is, which of several feeding-stuffs at given prices is really the cheapest. A simple example will serve to illustrate this : A farmer has more hay on hand than he needs ; shall he sell timothy hay at ;^ 1 2 per ton, or clover hay at ;^8 ? In other words, does the higher market price of timothy hay mean that it has a correspond- ingly higher feeding value? From Table III. (p. 34) we have the follow- ing figures for the actual amounts of food contained in the two : Dry matter. Digestible. Protein. Carbhydrates and fat. Total. Nutritive ratio. Timothy hay . . . ... Clover hay ... Per cent. 86.8 84.7 Per cent. 2.9 6.4 Per cent. 46.9 38.5 Per cent. 49.8 44-9 1 : 16.2 I : 6.0 We find that timothy hay does contain more total food than clover hay, but that the difference is not at all proportionate to the difference in price. From the amounts of digestible matter contained in one hundred pounds, with the prices for the same amount, it is easy to calculate the cost of one pound of digestible matter in each, as follows : Timothy Hay. 100 lbs. contain 49.8 lbs. digestible matter, and cost 60 cents. 60 cents ^49.8 = 1.205 cents, cost of i lb. of digestible matter. Clover Hay. 100 lbs. contain 44.9 lbs. digestible matter, and cost 40 cents. 40 cents -f- 44.9 = 0.891 cents, cost of i lb. of digestible matter. We thus see that the clover hay, at the assumed price, is a much cheaper source of food than the timothy. The latter has a relatively high market price, owing to the special demand for it for feeding horses. Moreover, the clover is not only a cheaper source of food, but is also much richer in protein, which is usually the most expensive ingredient of feeding-stuffs, either to produce or to buy. The relative fertilizing 20 THE PENNSYLVANIA STATE COLLEGE. value of the timothy and clover would also enter into a consideration of the question of their sale, but this branch of the subject will be considered in a subsequent section. More commonly the question is a question of the choice of grain feeds. For example, the following feeds are available to a dairy farmer : Oats @;^iS per ton (24c. per bu.). Wheat bran @ 14 per ton. Wheat middlings @ 16 per ton. Hominy chop @ 14 per ton. Dried brewers' grains @ 14 per ton. Gluten feed @ ^7 per ton. Cotton-seed meal @ 20 per ton. Old process linseed meal . . . . @ 18 per ton. The prices given above have been assumed arbitrarily and do not purport to represent present market prices, but have been chosen to illustrate the principles involved. The first step is to see how much the actual food, that is, the digest- ible matter, of these feeding-stuffs costs. Taking the percentages of total digestible matter from from Table III. (p. 34) and the prices as given above, and dividing the second by the first, exactly as in the illustration with the timothy and clover hay, we get the following : Digestible matter in 100 lbs. Cost of 100 lbs. Cost of I lb. of digestible matter. '. ■ Oats Wheat bran Wheat middlings ... Hominy chop ... Dried brewers' grains Gluten feed .... Lbs. 62.4 57-4 73-7 86.6 63-5 82.7 80.9 77.8 Cents. 75 70 «o 70 70 85 1. 00 90 Cents. I.202 I.2I9 1.085 0.808 1. 102 1.028 1.236 I.I57 Linseed meal (old process) From the figures in the last column of the above table we see that hominy chop is relatively the cheapest of these feeds. Feeds Hke oats and wheat bran are excluded as too costly at these prices, although when the market for them rules lower they might be preferred. We will assume that the coarse fodder on hand is sufficient to give each animal per day and head the amounts stated in the previous section namely, fourteen pounds corn forage and eight pounds clover hay. With these amounts we should have the following ration : COMPUTATION OF RATIONS FOR FARM ANIMALS. 21 Fourteen pounds corn forage . Eight pounds clover hay . Four pounds corn meal . . . Dry matter. Lbs. 8.09 6.78 3-40 18.27 Digestible. Protein. Lbs. 0-3S 0.51 0.22 I.C8 Carbhydrates and fat. S-oS 3.08 2.84 10.97 Total. Lbs. 5-40 359 3.06 12.05 Nutritive ratio. The rest of the feed required must be bought. If it were simply a