THE UNIVERSITY OF ILLINOIS LIBRARY MNVERMIY (j AGR/CULTURF NOTICE: Return or renew all Library Materials! The Minimum Fee for each Lost Book is $50.00. The person charging this material is responsible for its return to the library from which it was withdrawn on or before the Latest Date stamped below. Theft, mutilation, and underlining of books are reasons for discipli- nary action and may result in dismissal from the University. To renew call Telephone Center, 333-8400 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN L161 O-1096 70 UNIVERSITY OF ILLINOIS Agricultural Experiment Station BULLETIN No. 250 THE VALUE OF MINERAL SUPPLEMENTS IN SWINE FEEDING BY JOHN B. EICE WITH AN INTRODUCTION BY H. H. MITCHELL URBANA, ILLINOIS, MAY, 1924 CONTENTS OF BULLETIN No. 250 PAGE INTRODUCTION 89 The Mineral Requirements of Animals 89 The Mineral Problem in Swine Feeding 91 Improving the Calcium Retention of Swine on Grain Rations 91 Improving the Quality of Bone on Grain Rations. . 92 The Value of Different Minerals as Supplements to Grain Rations 93 Mineral Mixtures Homemade and Commercial 95 The Economic Value of Mineral Feeding 96 FEEDING EXPERIMENTS 97 EXPERIMENT I: MINERAL SUPPLEMENTS USED WITH CORN, MIDDLINGS, AND TANKAGE, WITH AND WITHOUT RAPE PASTURE 98 EXPERIMENT II: PROVIDING A MINERAL MIXTURE IN THE SELF-FEEDER TO PIGS ON PASTURE 100 EXPERIMENT III: MINERAL SUPPLEMENTS USED WITH CORN, LINSEED OIL MEAL, AND MIDDLINGS, WITH ACCESS TO BLUE- GRASS PASTURE 102 MINERAL SUPPLEMENTS FOR PREGNANT AND LACTATING SOWS 106 CONCLUSIONS . . 110 THE VALUE OF MINERAL SUPPLEMENTS IN SWINE FEEDING BY JOHN B. EICE, 1 ASSISTANT CHIEF IN SWINE HUSBANDRY WITH AN INTRODUCTION BY H. H. MITCHELL, ASSOCIATE CHIEF IN ANIMAL NUTRITION INTRODUCTION THE MINERAL REQUIREMENTS OF ANIMALS Animals require for their proper growth and development twelve or fifteen, or possibly more, mineral elements, retaining daily during active growth two to three ounces for every thousand pounds of live weight. Fortunately it is not necessary in the practical rationing of farm animals to consider more than two or three of these elements. The largest requirement of mineral matter by growing, breeding, and lactating animals is for bone growth, or for the secretion of a food (milk) capable of supporting vigorous bone growth in their young. About 85 percent of the ash of bones is calcium phosphate. Hence, quantitatively, the most urgent need for mineral matter by farm animals is for calcium and phosphorus. It has been estimated that over 80 percent of the mineral matter retained in the bodies of grow- ing animals is calcium and phosphorus. It is natural, therefore, that the calcium and phosphorus requirements of animals and the calcium and phosphorus content of farm feeds should have received the most attention in experiments concerned with the mineral requirements of farm animals. Such experiments have yielded no definite evi- dence that farm rations are ever likely to be deficient in the many other mineral elements needed by growing animals, with the exception of iodin. This element, occurring in mere traces in most feeds, may at times, and particularly in certain restricted localities, be present in deficient amounts in otherwise well-balanced rations. This deficiency has been definitely demonstrated with breeding animals, and occasionally with young growing animals, especially calves. In the case of breeding animals it has been indicated by the birth of dead offspring marked with those deformities, such as hairlessness and goiter, resulting from the abnormal develop- ment and functioning of the thyroid gland. The administration of small amounts of potassium iodid or sodium iodid to breeding animals 1 In Experiment III, reported on pages 103 to 110, the bone measurements and analyses were made by the Division of Animal Nutrition, and the responsibility for the discussion of these data is assumed by H. H. Mitchell. 90 BULLETIN No. 250 [May, in those localities where goiter is prevalent, seems to be an effective remedy against this condition, but offers no excuse for the general administration of iodids to farm stock. The evidence of a possible deficiency of farm rations in other mineral elements, such as iron, needed by animals in very small amounts and present in mere traces in farm feeds, is admittedly negative. However, until a definite suspicion of such defiencies is justified by experimental evidence, a general consideration of the mineral requirements of farm animals may reasonably be restricted to calcium and phosphorus. It may be stated as a general proposition that the leguminous roughages are adequate sources of calcium and phosphorus except possibly under conditions of excessive demands for bone-forming materials, as with high-producing dairy cows. The non-leguminous roughages are much inferior in this respect, particularly as regards their content of calcium. Pasture grasses are known to vary in their mineral content according to the composition of the soil upon which they are grown. In fertile regions, however, they can be considered reliable tho not particularly rich sources of mineral nutrients. From these general observations, it may be concluded that animals raised largely upon liberal amounts of a good roughage are not in danger of mineral under-nutrition. Sheep and beef cattle come within this category. Dairy heifers and dairy cows offer peculiar problems of their own. The dairy heifer, by being generally removed from its dam at an early age and fed artificial rations composed largely of feeds low in bone-forming nutrients, may often receive insufficient mineral nourishment. The dairy cow, because of the extensive drain on its mineral stores occasioned by the secretion of amounts of milk enlarged to unnatural proportions by long and careful breeding, should, in the most successful dairy practice, be fed rations carefully balanced with respect to calcium and phosphorus. The horse, also, should be raised with special regard to its mineral supply, since its commercial value depends so much upon optimum bone strength and development. In contrast with the roughages, the seeds and their by-products cannot be considered good bone foods. While some of these feeds, particularly cottonseed meal and wheat bran, are among the richest sources of phosphorus available on the farm, their content of calcium is uniformly low, and rations composed largely of seeds and their by-products may be considered generally deficient in calcium, except for the maintenance and fattening of mature stock. Hence, in the feeding of growing pigs, brood sows, and growing and laying poultry, there is urgent call for a proper supplementing of the ration in order to correct its calcium deficiencies. 1924] MINERAL SUPPLEMENTS IN SWINE FEEDING 91 THE MINERAL PROBLEM IN SWINE FEEDING For physiological and economic reasons the major part of the ration of swine will always be grain, and the nutritive deficiencies of grains as feeds are therefore of first importance to swine feeders. The advantages of increasing the protein of cereal rations by the addi- tion of supplements rich in this nutrient, such as skim milk, tankage, linseed oil meal, soybeans, and soybean oil meal, seem now well estab- lished, and such supplements constitute an essential part of the most successful rations for swine. The advantages of vitamin supplements to cereal feeds are just beginning to be investigated, and while it seems that with some cereal feeds such supplementing is required, no gen- eral recommendations are warranted at present. The need of mineral supplements to cereal feeds has been realized for many years, but whether this correction should be made by the use of feeds rich in minerals, or by the use of minerals as such, is still an open question. If minerals as such are to be recommended, what advantages may be expected from their use, and what minerals are the most valuable as supplements to cereal grains and by-products, are questions upon which the experimental evidence is conflicting. Quantitatively the greatest need of minerals by the growing ani- mal, the pregnant animal, and the lactating animal is for calcium and phosphorus, the main constituents of bones. The greatest mineral deficiency of cereals is in calcium. Since rations for swine consist so largely of the cereal grains and their by-products, the question of mineral supplements in swine feeding involves mainly calcium and the use of feeds and minerals that are richest in this element in forms suitable for animal use. It seems possible also that the phos- phorus content of cereals is not sufficiently high, when considered in relation to the amounts consumed by pigs, to provide fully for the requirement of maximum bone growth, tho the evidence on this point is not sufficient to warrant a definite conclusion. The need of common salt, also, by swine as a supplement to their cereal feed is fully recognized. IMPROVING THE CALCIUM KETENTION OF SWINE ON GRAIN KATIONS It has been clearly shown by careful balance experiments that cereal feeds alone, and in particular corn, do not provide enough calcium to permit of any considerable retention of this element for bone and tissue growth. In fact, Forbes contends that corn alone, or corn supplemented by the seed by-products, linseed oil meal and wheat middlings, cannot maintain the growing pig in calcium equilibrium. While his mineral balance data support this conclusion, the slaughter records and carcass analyses, where such were made, in most cases indicate either no loss of calcium and no impoverishment 92 BULLETIN No. 250 [May, of the skeleton in this element, or a considerable growth of skeleton and a corresponding retention of calcium. 1 Such records appear to be of more significance than the results of short balance periods. A per- sistent negative calcium balance cannot, therefore, be considered char- acteristic of animals subsisting upon even such poor mineral feeds as corn and the feeds with which it is commonly fed. In other words, on a low calcium intake the animal body possesses the power to conserve its calcium stores against any serious depletion, by a more economical use of the calcium in its feed. However, it is equally clear that mineral additions to such rations, either in feeds rich in calcium compounds, such as skim milk and tankage, or in mineral supplements, may greatly increase the reten- tion of calcium and phosphorus and permit the normal growth of bone. From slaughter tests performed by Forbes and his associates on pigs subsisting for twelve weeks on rations of corn alone, and on corn plus a single supplementary feed (Ohio Bulletin 285), it may be computed that the average daily gain or loss of calcium and phos- phorus in the skeleton alone was as follows for the different lots: TABLE 1. AVERAGE DAILY GAINS OF CALCIUM AND PHOSPHORUS IN THE SKELETONS OF PIGS ON RATIONS OF CORN AND A SUPPLEMENTARY FEED From Slaughter Records Reported by Forbes in Ohio Bulletin 285 Ration Slaughter weight of pigs Average daily gain of calcium Average daily gain of phosphorus Corn alone Ibs. 183 gms. +0.069 gms. +0.044 Corn and soybeans 172 -0.229 0.086 Corn and oil meal 199 +0.220 -+ 0.136 Corn and middlings 201 +0.081 +0.118 Corn and tankage 190 -f 1.202 +0.583 Corn and skim milk 216 +1.882 +0.900 The marked effect of tankage and skim milk in increasing the retention of the bone-forming elements, calcium and phosphorus, is clearly evident from these figures. In short balance periods, in which the intake and outgo of calcium have been determined, daily reten- tions of 3 to 4.5 grams of calcium have been obtained at the Ohio Station on seed rations supplemented with minerals. IMPROVING THE QUALITY OF BONE OF SWINE ON GRAIN RATIONS In experiments at the Nebraska Station (Bulletin 107), as well as at the Ohio Station (Bulletins 283 and 347), it has been shown that mineral supplements and feeds rich in minerals do not have an 1 Ohio Agricultural Experiment Station Bulletin 213, page 288 ; and Bulletin 283, pages 135, 347, and 67-68. 19SS4] MINERAL SUPPLEMENTS IN SWINE FEEDING 93 appreciable effect, if any at all, on the dimensions or the volume of the bones, but that they may markedly increase the density, the thick- ness of wall, the hardness, and the breaking strength. As Forbes has well said, big bone can be obtained by breeding for it, but dense bone only by feeding for it. The following figures taken from the Nebraska report show clearly the favorable effect of certain rations on the breaking strength of bones. TABLE 2. COMPARATIVE BREAKING STRENGTH OF BONES OF HOGS ON VARIOUS EATIONS Average Breaking Strength per 100 Pounds Live Weight Ration Femur Tibia Humerus Ulna-radius All bones Corn alone 276 252 434 341 325 Corn 75, shorts 25 343 309 555 37ti 396 Corn 25, skim milk 75 ... Corn 90, tankage 10 .... Corn 90, ground bone 10 462 559 646 360 409 465 685 740 898 529 611 715 509 580 681 An increase in strength of more than 100 percent was secured by the feeding of ground bone with corn, and only a slightly smaller increase by the feeding of tankage. These increases are much larger than those reported by Forbes, who, however, started his experiments with heavier pigs, weighing 100 pounds or more. There seems to be no definite upper limit to the storage of minerals in the skeleton and to the increased density and strength associated with it. THE VALUE OF DIFFERENT MINERALS AS SUPPLEMENTS TO GRAIN RATIONS Altho there is every reason to believe that the rations of growing pigs, and of breeding stock as well, may be balanced properly with respect to minerals by the use of sufficient amounts of mineral-rich feeds and pastures, when such feeds are not available or are not in common use the possibility of using mineral supplements to advantage may then be considered. Several experiment stations have investigated the value of various mineral mixtures in increasing the daily gains of growing pigs and in decreasing the cost of gains. There are, how- ever, very few experiments on record comparing individual mineral substances. Experiments of this character have been reported re- cently by Forbes and his associates at the Ohio Station in Bulletin 347. The experiments therein reported are very complete and con- stitute a notable contribution to the literature on the subject. The basal ration in those experiments consisted of corn meal 7 parts, wheat middlings 1 part, and linseed oil meal 1 part. The mineral supplements tested included rock phosphate floats, ground limestone, a precipitated calcium carbonate, precipitated bone flour, a 94 BULLETIN No. 250 [May, special steamed bone flour, and in one experiment, the less common supplements, whiting and marl. When these supplements (except the last two) were added to the basal ration in amounts providing the same daily quantity of calcium (5 grams), the bone and carbonate preparations were about equally efficient in causing increased reten- tion of calcium above that secured on the basal ration alone. The rock phosphate, however, was distinctly inferior in this respect. Re- tention of calcium and phosphorus was 50 to 60 percent greater with the other supplements than with rock phosphate. It was shown by examination of certain leg bones that with the same intake of supple- ments, the volume of the bone was not greatly affected by the method of feeding. In hardness, density, and breaking strength, however, distinct differences appeared among the groups. No distinction was noted between the bones of pigs receiving no minerals and those of pigs receiving rock phosphate. In spite of a greater retention of calcium occasioned by the rock phosphate supplement, the strength of the bones was not improved over the bones of the no-mineral pigs. The supplements having the most marked effect on the physical prop- erties of the bones were the precipitated calcium carbonate and the steamed bone. These supplements in eighty-six days caused an aver- age increase in the breaking strength of the bones of 25 to 45 percent over the no-mineral ration. The initial weight of these pigs was 137 pounds; with younger pigs probably much greater increases would have been obtained. When the supplements were self -fed (mixed with 3 percent of common salt), one to each group of pigs, the steamed bone proved much more palatable than the other bone preparations and than ground limestone which in turn were distinctly more palatable than the rock phosphate and the precipitated calcium carbonate. Again the rock phosphate produced no greater strength of bone in relation to live weight than did the basal ration without mineral supplement, while all other supplements caused marked and nearly equal increases in bone strength. It is to be noted that the large excess of steamed bone consumed, as compared with the intake of the other supplements, apparently produced no distinctly greater effect than a quantity half as large produced in the other experiments, except possibly as regards bone hardness. In the two experiments reported in this bulletin in which the di- gestibility of the rations was determined, it was found that the added mineral supplements had no effect on the digestibility of protein, car- bohydrate, or fat. It is also worthy of note that the carbonate minerals could not be clearly distinguished from the phosphate minerals in these experiments in their effect on calcium or phosphorus retention or on the strength and density of bone. In other words, there is no reason to doubt that the basal ration used contained sufficient phosphorus 1924} MINERAL SUPPLEMENTS IN SWINE FEEDING 95 for maximum bone growth and development. The advantage, if any, of calcium phosphate supplements over calcium carbonate supplements is in their greater palatability and the greater tolerance of the digestive system for phosphates than for carbonates. Substantially the same conclusion is justified from the balance ex- periments reported by Hart, Steenbock, and Fuller in Eesearch Bulle- tin 30 of the Wisconsin Agricultural Experiment Station. The Wis- consin investigators have had better success with rock phosphate as a mineral supplement to a seed ration than has Forbes, tho their data are not as numerous as those of Forbes, and in some respects their results are inexplicable. The predominant need for phosphorus rather than for calcium by swine on cereal rations, indicated by earlier ex- periments at the Wisconsin Station (Research Bulletin 1), has not been confirmed at other stations and is in direct contradiction to the more extensive work of Forbes. MINERAL MIXTURES HOMEMADE AND COMMERCIAL Mineral supplements are cheap and concentrated sources of cal- cium and phosphorus, and if wisely chosen, may correct satisfactorily the mineral deficiencies of grain rations. For this purpose, both phos- phate and carbonate preparations of calcium may be used. Bone meal, particularly steamed bone meal, and finely ground high-grade limestone or commercial calcium carbonate preparations would seem to be the most efficient, judging from the Ohio results, while finely ground rock phosphate has not been found particularly effective ; its cheapness and more general availability on the farm, however, must also be considered. Good results have been reported from the use of a mixture of acid phosphate, wood ashes, and salt in the proportion of 10 to 10 to 1 by the Purdue Agricultural Experiment Station. The effectiveness of slaked lime has not been specifically investigated. The need of common salt by all farm stock, but particularly by animals consuming large amounts of roughage, is well recognized. In the compounding of mineral mixtures for swine, salt is also valuable as an appetizer, and is often included, therefore, in amounts far larger than necessary. While iodids in small amounts are of proven value in certain specific instances, as already explained, their general use in mineral mixtures is unnecessary and therefore not warranted. The inclusion of purgatives, drugs, and inert fillers in mineral mixtures is to be condemned. It is because of the general use of such substances, rather than substances of nutritive value, that commercial mineral mixtures should be regarded with suspicion. Glauber's salts, Epsom salts, potassium chlorid, lye, and copperas, have no place in the rations of healthy farm animals. As Forbes so aptly says when J$ BULLETIN No. 250 [May, speaking of mineral mixtures for swine, "healthy pigs do not need these drugs, and sick pigs need medicines chosen with reference to the particular disorders from which they suffer." The use of inert substances, such as slack coal, charcoal, and sulfur, cannot be said to add anything to the value of mineral mixtures, tho possibly they may improve intestinal conditions in some unknown way. The long list of substances that are often mentioned as possible constituents of mineral mixtures, appears to have confused the popular mind on this subject. There is nothing mysterious or particularly complicated about the compounding of a satisfactory mineral mixture. A mixture consisting of common salt (or tankage) 10 parts, finely ground limestone 45 parts, and steamed bone meal 45 parts, has as much to commend it as any other for swine feeding. This mixture contains only calcium supplements of proven value, with a small amount of salt or tankage to increase its palatability and to contribute sodium and chlorin, in which grains are deficient. It is therefore unnecessary and wasteful to purchase and use complex commercial mixtures. Mineral supplements should be used in swine feeding when skim milk, tankage, or legume pasture is not available. The supplements may be mixed with the ground concentrates in the proportion of 2 to 100, or may be self -fed. THE ECONOMIC VALUE OF MINERAL FEEDING While the value of a greater concentration of calcium in the ration of swine than that afforded by cereal or all-seed rations seems well established in so far as bone growth and development are concerned, its value is not so clear from the purely economic standpoint in the raising of pigs for market. The addition of calcium supplements to cereal or all-seed rations has not in all cases produced more rapid or more economical gains, the experience of the Ohio and Wisconsin Sta- tions being in this particular in close agreement. In the experiments performed at the Iowa Experiment Station, and reported in farm journals and elsewhere, somewhat more rapid and economical gains resulted from the use of mineral supplements with rations of cereals, seed by-products, and blood meal, but when such rations were supple mented with adequate amounts of tankage or good legume pasture, no obvious beneficial results were in general obtained thru the use of mineral mixtures. However, the practice of feeding mineral supplements to growing and fattening swine has become so common among farmers and stock feeders, and the claims frequently made for mineral mixtures have become so extreme that the situation calls for investigation. The fol- lowing series of experiments was therefore undertaken, primarily to 1924} MINERAL SUPPLEMENTS IN SWINE FEEDING 97 determine whether good swine rations are in need of mineral supple- ments. The selection of the minerals used in these experiments was based more upon their common availability on Illinois farms than upon any proven superiority over other minerals. In fact, in the latter re- spect the selection was not particularly fortunate, as judged by the latest findings of the Ohio Experiment Station. Most of the work was concerned simply with the rate and economy of gains of the several groups of pigs, tho the last year 's work involved also the measurement and analysis of bones. FEEDING EXPERIMENTS The 240 pigs used in these experiments were raised on the Univer- sity Farm, and consisted of Poland Chinas, Duroc-Jerseys, Chester Whites, and Hampshires, with some Berkshires, Large Yorkshires, and cross-breds. All lots contained 20 pigs at the start of the experiment. Lots to which minerals were offered were treated uniformly with other lots receiving the same ration without added minerals. Data bearing on the economy of gains were taken in each test, and in some cases the bones were analyzed after slaughter. The 1 experiments, for the most part, covered the period from shortly after weaning time until an average marketable" weight of 225 pounds had been attained in each lot. The pigs were weighed indi- vidually every two weeks during the experiments, the weighing being done before the morning feed was given. The pens used for dry-lot feeding were free from vegetation. They were provided with small movable houses and sunshades in winter and summer. The feeds used were No. 2 to No. 4 yellow shelled corn, 60 percent tankage, old process linseed oil meal, and grey flour middlings. The mineral supplements used were slack coal, charcoal, air-slaked lime, ground limestone, rock phosphate, and salt. The coal was a cheap grade of slack coal. The charcoal was a good grade of commercial charcoal. The air-slaked lime was commercial slaked lime produced from quicklime. The limestone and rock phosphate were secured from the fertilizer bins of the Agronomy Department of the University. The limestone was above 90 percent purity and contained about 36 per- cent calcium. The rock phosphate contained 13 percent phosphorus as a minimum, which would mean that the calcium content was about 31 percent. The salt was ordinary barrel salt. The feed costs in this bulletin are expressed in terms of pounds of feed and mineral supplements required for 100 pounds of gain. From these data, the cost of gains can be calculated at the prevailing prices. No attempt was made to determine the amount of forage consumed. 98 BULLETIN No. 250 [May, EXPERIMENT I: MINERAL SUPPLEMENTS USED WITH CORN, MIDDLINGS, AND TANKAGE, WITH AND WITHOUT RAPE PASTURE The first year's work was concerned with the advisability of pro- viding mineral supplements for pigs on a ration of corn, middlings, and tankage, with and without access to rape pasture. One hundred and twenty pigs, averaging 43 pounds in weight, were divided into six lots and were started on experiment June 21, 1919. Three of the six lots were fed in dry lot and three were allowed rape pasture in ad- dition to their concentrate ration. The pigs in Lots 1, 2, and 3 were hand-fed a full ration of corn and were allowed about 0.4 pound of tankage and 0.8 pound of middlings daily per head after the first four weeks. For Lots 4, 5, and 6 (the pasture lots), the allowance of tankage and middlings was cut down from these figures. During the period of pasture feeding (from June 19 to October 11), the daily allowance of tankage was from 0.25 to 0.30 pound, and of middlings from 0.5 to 0.75 pound per head after the first few weeks. After October 11 these three lots were given 0.3 pound of tankage and 0.75 pound of middlings per head daily. The pigs in Lots 1 and 4 received no mineral supplements. Lots 2 and 5 were offered four supplements in separate compartments of a self-feeder, i.e., coal, limestone, rock phosphate, and salt ; while Lots 3 and 6 were given their choice of six supplements, including the above four with the addition of charcoal and air-slaked lime. All lots were continued to an average weight of approximately 225 pounds. RESULTS OF EXPERIMENT I Little difference was found in the feed consumption or in the rate and economy of gains among the groups fed in dry lot. While the pigs receiving no minerals made the slowest and most expensive gains on the average, the differences as compared with the other lots were probably too small to be significant. Among the lots on forage there were also no considerable differ- ences as regards feed consumption or rate or economy of gains. On an average, the no-mineral pigs made the slowest but also the most economical gains. In all lots more of the coal was consumed than of all other mineral supplements put together. The consumption of coal by Lot 5 was par- ticularly great, twice as much being consumed as by any other lot. Contrasted with this large consumption of coal, comparatively little of the calcium supplements (limestone and rock phosphate) was eaten. A close correlation between the consumption of coal and of calcium supplements is to be noted such that the greater the consumption of MINERAL SUPPLEMENTS IN SWINE FEEDING 99 TABLE 3. EESULTS OF EXPERIMENT I Mineral Supplements Fed to Pigs on a Eation of Corn, Middlings, and Tankage, With and Without Access to Eape Pasture Lot No 1 2 3 4 5 6 Ration Corn, tankage, and middlings Forage None Rape Mineral supplements (free choice) None Self- fed Self- fed None Self- fed Self- fed No of pigs at beginning .... 20 18 196 (Ibs.) 43 130 225 .89 3.28 .37 .78 4.43 370 41 87 498 20 18 189 (Ibs.) 43 134 226 .95 3.31 .37 .78 4.46 349 39 82 470 (oz.) 1.18 .12 .09 .15 1.54 (Ibs.) 10.2 20 * 19 196 (Ibs.) 43 134 225 .91 3.30 .37 .78 4.45 362 40 85 487 (oz.) .89 .18 .13 .19 .26 .01 1.66 (Ibs.) 11.3 20 15 175 (Ibs.) 43 150 227 .98 3.44 .27 .67 4.38 353 27 69 449 20 19 182 (Hw.) 42 144 225 1.00 3.57 .27 .68 4.62 356 27 67 450 (oz.) 2.52 .05 .07 .18 2.82 (Ibs.) 17.5 20 20 189 (Ibs.) 42 142 230 1.01 3.64 .27 .68 4.59 361 27 68 456 (oz.) .99 .14 .10 .15 .31 .03 1.72 (Ibs.) 10.7 No of pigs at end Days on experiment Average weight per pig Initial weight Weight on Oct. 11 Final weight Daily gain Average daily ration Corn Tankage Middlings Total Concentrates per 100 pounds gain Corn Tankage Middlings Total Mineral supplements consumec daily per pig Coal Limestone Rock phosphate Salt Charcoal Air-slaked lime Total Mineral supplements consumec per 100 pounds gain NOTE. During the course of the experiment several pigs died or were re- moved for various reasons. In some cases substitutions were made. In brief, two pigs were withdrawn from Lot 1 on October 11 and 25, respectively, for lack of thrift. One of these pigs weighed 46 pounds when the average lot weight was 130 pounds; the other weighed 117 pounds when the average lot weight was 144 pounds. In Lot 2, one pig died on December 6 and one was withdrawn on Decem- ber 19 on account of inversion of the uterus. In Lot 3, one pig died as the result of vaccination on July 6 and was replaced by another pig; while on October 11 a second pig was withdrawn because of being badly ruptured. In Lot 4, five pigs died between October 8 and November 13, the cause of death being diagnosed as hemorrhagic septicemia. In Lot 5, one pig died on July 11 as a result of vaccina- tion and was replaced by another pig of approximately the same weight; while on November 25 a second pig died from what appeared to be hemorrhagic sep- ticemia. In Lot 6, one pig died on August 3, cause unknown, and was replaced by another pig; while on August 2 one pig was killed and was found to have cirrhosis of the cord. This pig was replaced by another of the same weight. 100 BULLETIN No. 250 [May, coal, the less the consumption of limestone and rock phosphate. The intake of salt was fairly uniform, averaging 1 part to 430 parts of concentrates, while that of air-slaked lime was insignificant. The daily concentrate ration, according to the average analyses of Forbes, contained about 5.5 grams of calcium for Lots 1, 2, and 3, and about 4.0 grams for the lots on forage. Since forage would furnish considerable calcium, all lots probably received sufficient amounts of this element entirely aside from its intake in the form of a supplement. The minerals fed Lots 2, 3, and 6 probably furnished 2 to 2.5 grams of calcium per head per day and those fed Lot 5 about 1 gram. EXPERIMENT II: PROVIDING A MINERAL MIXTURE IN THE SELF-FEEDER TO PIGS ON PASTURE The experiment of 1919 showed that pigs will consume only small amounts of calcium supplements when allowed free access to them in separate compartments of a self-feeder and when, also, they are allowed free access to coal. Apparently the consumption of large amounts of coal diminished their appetite for the more valuable cal- cium supplements. Since it seems advisable to feed mineral supple- ments to pigs in a self-feeder, further work was undertaken in 1920 to determine the value of a mineral mixture when offered to pigs in this manner. On July 10, 1920, four lots of 20 pigs each were started on experi- ment, receiving the following concentrate rations and having free access to blue-grass pasture : Lot 1. Two-thirds ration of corn. No mineral supplements. Lot 2. Two-thirds ration of corn. Free access to mineral mixture. Lot 3. Full ration of corn and 0.25 pound of tankage per head daily. No mineral supplements. Lot 4. Full ration of corn and 0.25 pound of tankage per head daily. Free access to mineral mixture. On October 2 all lots were removed from pasture and put on a full feed of corn and 0.4 pound of tankage daily per head. The mineral mixture used, consisting of coal 5 parts, and air-slaked lime, rock phos- phate, and salt each 1 part, was offered to Lots 2 and 4 thruout the ex- periment, during both pasture and dry-lot feeding. All lots were car- ried to an average weight of approximately 225 pounds. RESULTS OF EXPERIMENT II Little difference is to be noted in the feed consumption or the rate or economy of gains between comparable lots in this experiment. While the most economical gains were made by the two lots receiving MINERAL SUPPLEMENTS IN SWINE FEEDING 101 TABLE 4. RESULTS OF EXPERIMENT II Mineral Mixture Provided in a Self -Feeder to Pigs on Pasture Lot No 1 2 3 1 4 Ration on pasture 1 Two-thirds ration corn Full ration of corn and 0.25 pound of tankage per head daily Ration in dry lot Full ration of corn and 0.4 pound of tankage per head daily Mineral mixture None Self-fed None Self-fed No. of pigs at beginning. . . . No. of pigs at end 20 19 203 (Ibs.) 46 107 226 .89 3.96 .32 4.28 448 36 484 20 19 196 (J&B.) 16 109 224 .90 3.94 .31 4.25 440 35 475 (oz.) 2.04 14.2 20 19 227 (Jfo.) 46 75 227 .77 3.54 .24 3.78 461 32 493 20 16 224 (Ibs:) 46 79 229 .75 3.39 .23 3.62 450 31 481 (02.) 2.19 18.1 Days on experiment Average weight per pig Initial weight Weight on October 2 .... Final weight Daily gain Average daily ration Corn Tankage Total Concentrates consumed per 100 pounds gain Corn Tankage Total Mineral supplements con- sumed daily per pig . . . Mineral supplements con- sumed per 100 pounds gain NOTE. In this experiment also certain changes were made in each group of pigs owing to death or withdrawal and to substitutions. In Lot 1, one pig was withdrawn on July 29 because of scouring and ema- ciation and was replaced by another pig of approximately the same weight; on October 14 one pig was removed with hemorrhagic septicemia. In Lot 2, two pigs were withdrawn on July 24 and 29, respectively, and replaced by other pigs; while on October 2 four pigs wert withdrawn with hemorrhagic septicemia, three of them being put back on experiment two weeks later. In Lot 3, one pig was re- moved on July 29 and another on August 7, substitutions being made; while on July 31 four pigs died of the heat and were replaced by four others of nearly the same weight ; on October 2 one pig was removed from experiment because of fail- ure to grow, weighing only 27 Ibs. when the average weight of the lot was 75 Ibs. A substitution was made for one pig removed from Lot 4 on August 14 because of hemorrhagic septicemia, and removal of three pigs for the same cause was made on September 18, October 2, and January 20, with no replacements; on January 22 another pig was withdrawn because of lack of thrift. This latter pig weighed 65 Ibs., while the average lot weight was 188 Ibs. 1 All lots were on blue-grass pasture until October 2. minerals, the differences are not great enough to justify the conclusion that free access to mineral supplements definitely improved the rations used in this test. As a matter of fact, under the prices prevailing dur- ing the experiment, the cost of mineral supplements and concentrates 102 BULLETIN No. 250 [May, per 100 pounds of gain in Lot 2 were practically the same as the cost of concentrates per 100 pounds gain in Lot 1 ; while for Lot 4 as compared with Lot 3 the cost of gains was greater when mineral sup- plements were fed. In Lots 2 and 4 the consumption of mineral supplements, and par- ticularly calcium supplements, was greater than in the experiment of the preceding year when all supplements were offered in separate com- partments of the self-feeder. However, in spite of this increased in- take of calcium, no marked improvement in the ration was shown, in- dicating that the concentrate ration used needed no further supple- menting than that afforded by access to pasture while this was available. EXPERIMENT III : MINERAL MIXTURE UED WITH CORN, LINSEED OIL MEAL, AND MIDDLINGS, WITH ACCESS TO BLUE-GRASS PASTURE The purpose of the third experiment was to determine the ad- vantages, if any, of adding mineral supplements to a ration of corn, linseed oil meal, and middlings, when the pigs had access also to blue- grass pasture. The mineral mixture used contained coal 5 parts, and ground limestone, rock phosphate, and salt each 1 part. By actual analysis, this mixture was found to contain 12.38 percent of calcium. The feeds used in this experiment were also analyzed, with the re- sults given in Table 5. TABLE 5. ANALYSIS OF FEEDS USED IN EXPFRIMENT III (Percent of Fresh Substance) Dry matter N-free extract Crude protein Ether extract Ash Crude fiber Wheat middlings .... Corn 90.93 89.33 60.73 76.98 17.79 8.57 1.53 0.72 4.91 1.24 5.97 1.82 Oil meal . . 90.52 45.84 29.21 1.46 6.07 7.94 ECONOMY OP GAINS IN EXPERIMENT III The average daily feed consumption per pig was practically the same in both lots, tho the rate and economy of gains were more favor- able in the group having access to minerals. The pigs offered the mineral mixture gained an average of 0.07 pound more per day than the pigs receiving no minerals, at a saving of 37 pounds of feed per 100 pounds of gain. Statistical analysis of the individual daily gains indicates, however, that the average lot difference in rate of gain is of no significance. The cost of gains was somewhat less in the lot fed mineral supplements than in the lot not so fed, when the feeds and supplements were charged at the prices prevailing during the experi- 1924} MINERAL SUPPLEMENTS IN SWINE FEEDING 103 ment. The consumption of mineral supplements by Lot 2 was low as compared with that in the preceding experiments, about one pound being consumed per pig every 20 days. A striking difference between the two lots of pigs was noted in the amount of rooting in the pasture. The pigs receiving no mineral supplements, rooted up their pasture completely, while the lot receiving minerals did no considerable rooting. SIZE AND COMPOSITION OF THE BONES OF THE PIGS IN EXPERIMENT III t At the conclusion of this feeding test, five pigs from each lot were slaughtered at a local slaughter house and the leg bones removed for measurement and analysis. At the same time, six sows from Lot 1, and five from Lot 2, were bred and continued on their respective rations until litters were farrowed and weaned. TABLE 6. EESULTS OF EXPERIMENT III Mineral Mixture Fed to Pigs on a Ration of Corn, Linseed Oil Meal, and Middlings, With Access to Blue-Grass Pasture Lot No 1 2 Ration Full ration of corn, linseed oil- meal, and middlings Access to blue-grass pasture. Mineral mixture None Self-fed No. of pigs at beginning 20 19 144 (Ibs.) 65 206 .93 3.39 .51 .79 505 * 365 55 85 20 19 144 (Ibs.) 64 211 1.00 3.40 .51 .79 468 338 51 79 (Of.) .83 (Ibs.} 5.14 No. of pigs at end Days on experiment Average weight per pig Initial weight Final weight Daily gain Average daily ration per pig Corn Linseed oil meal Middlings Concentrates consumed per 100 pounds gain Corn .... Linseed oil meal . . Middlings . Average daily consumption of mineral mixture per pig Mineral mixture consumed per 100 pounds gain NOTE. On July 30 three pigs were removed from Lot 1 for lack of thrift and were replaced by three other pigs weighing considerably more; on November 12 one pig was removed from this group because of sickness, no replacement being made. In Lot 2, two pigs were removed on August 6 and September 25, respec- tively, because of injury, a substitution being made for the first pig removed but not for the second. 104 BULLETIN No. 250 [May, l a *f 00 O i * "5 IN CO CN IN 'J' CN iii S'swoeoo^i >- OS ^^ O t^ O Issssss U5 CO i ^f 1C Tt< CN lO IN IN i O O CO r-i 3* u CD (>. CO CO i<5 CO IO C CO 1C t- CO COCNCNOW5CO OOOOl^CNOS CO CO o o r- o ^j< us -41 1 r^ CN co co co co CN co . IN CO CO .-i CO "3 oocsocoo g Ttl Id CO <* 1-1 CO OSOOO-HCOO! v co co co co s*..*t CO O *& "& CD t CN <*< -H CO -* 'O COCNCNCNCNCN & % IN 1984] MINERAL SUPPLEMENTS IN SWINE FEEDING The results of the measurement of bones from the pigs killed at the termination of the experiment are given in Table 7, and the results of their analysis for moisture, protein, and ash, in Table 8. A study of Table 7 does not reveal any distinctive differences as regards the size of bone between the two lots of pigs. However, the pigs of Lot 2 tended distinctly to develop bones of greater specific gravity than the pigs of Lot 1, particularly with respect to the humerus and the femur. From the analytical results summarized in Table 8, no marked differences in the composition of the bones appeared to exist between the two groups of pigs. The bones of pigs having access to mineral supplements had a much higher average ash con- tent (dry basis) than those of the pigs not having access to mineral supplements, but individual differences among the pigs within the two lots were so great that no definite significance can be attached to the average difference. However, as the last column shows, there seems to be a distinct difference as regards, the weight of ash per cubic centimeter of volume, the average figure for the five pigs of Lot 1 being 0.317 gram, and for Lot 2, 0.351 gram. Only one case of overlapping occurs between the individual figures of the two groups, the highest value for Lot 1 being 0.329 gram, and the lowest for Lot 2, 0.328 gram, so that the difference evidently possesses consider- able significance. The mineral mixture offered to the pigs in Lot 2 apparently had a distinctly favorable effect in developing denser and probably stronger bone than would have been produced otherwise. TABLE 8. CHEMICAL ANALYSIS OF BONES FROM FIVE PIGS IN EACH OF THE LOTS OF EXPERIMENT III No. of pig Wt. of pig Wt. of fresh bones Total moisture in fresh bones Crude protein Crude ash Ash per cc. of vol. Calculated on dry basis Lot 1 Receiving No Mineral Supplements Ibs. gms. perct. perct. perct. ffm. 93PC 223 756 37.64 26.22 39.5S .324 9DJ 194 785 36.70 23.14 39.97 .329 40DJ 177 672 31.94 24.70 36.18 .311 43DJ 195 689 33.28 25.83 36.23 .300 30DJ 224 570 35.27 26.67 38.92 .320 Average 202.6 694.4 34.93 25.91 38.18 .317 Lot 2 Having Access to a Mineral Mixture 33DJ 240 752 31.73 27.20 44.59 .404 ODJ 191 610 37.25 26.36 43.00 .356 13DJ 190 673 38.44 27.39 41.09 .332 30DJ 196 653 31.21 24.80 37.72 .333 3PC 247 837 34.58 27.53 38.95 .328 Average 212.8 705 34.64 26.66 41.07 .351 106 BULLETIN No. 250 [May, MINERAL MIXTURE FOR PREGNANT AND LACTATING SOWS FEED AND REPRODUCTION RECORDS The feed and reproduction records of the sows selected from the two lots of Experiment III are given in Tables 9 and 10. While the average daily feed consumption of the two groups was approximately the same, .the sows offered the mineral mixture gained faster at a much lower feed cost than the sows without added minerals. In this connection it should be borne in mind that the pasture available during this test was winter pasture and very probably did not supple- ment to any considerable extent the calcium-poor concentrate rations. The sows of Lot 2 produced larger and heavier litters than the sows of Lot 1, on the average, tho the average weight per pig was larger for the litters of Lot 1. During the suckling period, the pigs in both groups did very poorly, owing to a chronic enteritis. The pigs weaned from the sows of Lot 1 were, on the average, heavier than those weaned from the sows of Lot 2. The individual data concerning the weaning weights of the pigs are given in Table 11. SIZE AND COMPOSITION OF BONES After their pigs were weaned, the sows were slaughtered and their leg bones taken for examination. In Table 12 are given the measure- ments of these bones and in Table 13 their composition. In this test the bones were analyzed for calcium by the McCrudden method, in addition to analyses for dry matter, protein, and ash. No significant differences in size or specific gravity of the bones are evident between the two groups of sows. The sows of Lot 2, being heavier than those of Lot 1, possessed heavier bones on the average, tho variations within each lot were so great that no true lot difference can be assumed. Similarly (Table 13) the composition of the bones of the two groups of sows did not seem to be affected by the inclusion of mineral supplements in the ration. The sows having access to the mineral mixture had on an average a higher percentage of ash and calcium in their bones and a greater weight of ash per cubic centi- meter of volume, but the individual differences within the two lots were so great that no positive conclusions concerning the meaning of these average differences seem justified. In other words, there is no positive evidence, from a physical and chemical examination of the leg bones of these sows, that the ration of corn, linseed oil meal, and middlings with access to winter pasture was improved at all from a nutritional standpoint by the self-feeding of the mineral mixture used in this experiment. The heavy strain of reproduction and lacta- tion seems to have been as well borne by the sows receiving no mineral supplements as by the sows having access to a mineral mixture. 1924] MINERAL SUPPLEMENTS IN SWINE FEEDING 107 TABLE 9. FEED AND WEIGHT RECORDS FOR PREGNANT Sows: EXPERIMENT III I ot No 1 2 Forage (winter pasture) Blue grass Blue grass Ration Corn Oil meal Corn Oil meal Middlings Middlings Mineral mixture Number of sows 6 5 Days on experiment (average) 149 143 Average weight per sow (Ibs.) (Ibs.) Initial weight 215 208 Final weight 311 340 Daily gain .64 . .87 Average daily ration per sow Corn 2.89 2.87 Oil Meal .50 .51 Middlings 1.94 1.98 Total 5.33 5.36 Concentrates per 100 pounds gain Corn 449 331 Oil meal 78 59 Middlings 301 228 Total 828 618 Average daily consumption of mineral mix- ture per sow (oz.) 1.22 TABLE 10. WEIGHTS OF LITTERS WHEN FARROWED Lot 1 No Mineral Supplements Sow 19DJ 90DJ 40DJ 59DJ ODJ 3PC Number of pigs Aver, weight (Ibs.) . . . 10 1.84 7 2.19 8 2.32 3 2.27 10 1.92 9 2.41 Lot 2 Access to Mineral Mixture Sow 99DJ 90DJ 40DJ 1DJ ODJ Number of pigs Aver, weight (Ibs.) . . . 11 2.38 10 1.96 10 1.93 10 1.55 6 1.37 TABLE 11. WEIGHTS OF LITTERS WHEN WEANED Lot 1 No Mineral Supplements Sow 19DJ 90DJ 40DJ 59DJ ODJ 3PC Number of pigs Aver, weight (Ibs.) . . . 3 23.3 4 20.5 8 14.0 2 16.0 5 17.2 5 21.8 Lot 2 Access to Mineral Mixture Sow 99DJ 90DJ 40DJ 1DJ ODJ Number of pigs 5 4 6 4 4 Aver, weight (Ibs.) . . . 15.2 14.7 16.0 13.7 17.5 NOTE. The pigs during their suckling period were troubled with necrotic enteritis, in consequence of which they did not attain normal weaning weights in eight weeks. 108 BULLETIN No. 250 [May, CO W fc OINCOOW-^O t^ CO * l^ IN -f TH US^lUSi-l (N OUSINCO er 00 w INr>.fCOO5lNCC t^ OINOOCO u; 03 1C C * t- Mas&i&s OUSUS t OOIN-H O IN CNN IN g rtOSU5(N 00 "ocjoo^osoooc OOOOUSUS O) r^cooooo t^- CO O "5 OS CO ^c t^ -< CO CQ IM CO CO CO CO (N O-*O>IN COCOCNCO CO 00 g o o co o oo o as "TjoOcOrHCOlOCO IN OOCNINUS Oi CNT)1OCVJ CO ."5 "5 CO SiMOOINN.'ncOO ^00 00 t TJIOO O OC ? "S US CN CO"t00 CO o a>o-.t~ oo -4^> g t^ 05 rH CO 00 O O3 g CC US rji'oo t^ 2 "OOOOOOOSMO3 OlOiOOi O> 1 Pi PI cc oo TJI CD in t^ oo to g'oocoorooi^ u iMiO O5rt f Sixno^o oo Q (N s U5 T)I co m iji oo o CO IN CONIC OCO O CO CD gCOCOi-KN^OST)' s w OUSOO * ^COCO M< " f 03 rtl-lrt rt I U) O5 8 Tji(3JiO-*OOO ,00 O US S M -i 00 Q ilN 1-1 (NiN^ i & US Tf OOCOOCN CO 00 00 -H O OS ,-,_CN-i 4-S O ^ g l35lt^OOOOO O5O5CO 00 i -i CO O IN f~ o r^ co CN t- ^ us CN CN IN IN CO IN CN *j -^ co 1-1 -H us r^ ou; ^Oi tN CO CO CO CO CO CD - 0> QO^QQQQ g OOO>OO5O ? TJI .-O5US > < QQQQQ S OO OO5 J> Til 0301 > 1924] MINERAL SUPPLEMENTS IN SWINE FEEDING 109 H I *rt h- I l-~ 2 I-H ^H as os TH U' 1C CO 1C O 1C CO OS OO * rt< (M 1C C Tf< Tt* T-H O CO t^ CO - OS OS co co rt< co co co co r^ co os os co >o t' 00 00 OS t-- CO Tf O ^ 00 OS 1C (N ^H t> i-H (M 00 >C l> co co "^t* co co ^f ^ -*(NCOCO.CflOS * 10 coos coco o l> CO 00 OS O CO , t- T-H 1-1 CO ^H (M CO S. - I-H CO I-H CO