SIMPLE vsnsus COMPLEX R'ATION ron LACTATING DAIRY cows _ THESIS FOR THE DEGREE OF M. s. ; ' RUssell E. Hoerod 1931 arm, m‘é‘w 2*; ‘ . c\ t I; ... -I‘ ‘;\.I”Aa- -?W§y?%%§VW§£§?#&fifi' ‘..".‘E(¢'£-," , ’ nu’ _ A‘ rh§$§§fi駑§%?“ ' EM «.5 72'.v.’:‘:'v’_‘ *r. ‘ M , .3 x 4 '3; ” M’ ‘ iii-3‘ ~§§'fi%‘.fl“§t‘\MI-‘ 7 . , 3 ‘ h§§‘~'9 . ‘ L"hm -Y* 15‘55 . k. 1 6339;; " S; fif‘gyfi' 4;, If" ' ' U c -- \' '." \ "‘13.“: ' <. fig. 5‘; #6 i: I ‘27“ ; ‘ IT I I, -. - , . .., . ,3 D “I, ‘ L I 'IIK'}£flQ .‘f‘-’ &“11? “ QI“ S ‘ f . .7 , .v.‘ I’. . "ggggsziegg' .. ' flVrbfl%K”fijfirw k "5 “I". 'l ‘ v1": 1 ..’ ,_ _ $8353.33." ‘ ~‘ ‘ g" V - {I ' ' A. '3} ‘-'§$’é; f. s" ' Fa— .. mt¢?p*7 ”33' {k .‘Mi'ro " “I 0 3‘” x. SIMPLE VERSUS COMPLEX RATION FOR LACTATING DAIRY COWS SIMPLE VERSUS COMPLEX RATION FOR LACTATIEG DAIRY COWS Thesis Respectfully submitted to the Graduate School of Michigan State College in partial fulfill- ment of the requirements for the degree of Master of Science. By Russell E. Horwood 1M 1931 ACKNOWLEDGMENTS The writer wishes to express his sincere appreciation to C. F. Huffman, Research Associate in Dairying, for his kindly guidance in laying out and conducting this experi- ment and his aid in the preparation of this manuscript. The writer wishes to acknowledge his indebtedness to E. L. Anthony, Professor of Dairy Husbandry, for making it possible for the writer to take up and carry out this work toward his Master's degree. The writer wishes to express his appreciation to G. W. Putnam, Director of Michigan State College Upper Peninsula Experiment Station, for providing facilities and assisting in the conducting of this experiment. 101737 TABLE OF CONTENTS page I Introduction a II Review and Discussion of Literature 1 A Requirement of Protein in Ration of Dairy Cow l 1. Protein 4 a Amino Acids 4 (1) Lysine 6 (2) Tryptophane 8 (3) Cystine 10 (4) Tyrosine 15 (5) Histidine 15 (6) Histidine and Arginine 17 (7) Other Amino Acids ‘ 20 b Protein Level 22 2. Energy 25 5. Vitamin 27 a Vitamins - General 27 (1) Vitamin A 28 (2) Vitamin B so (3) Vitamin c 31 (4) Vitamin D 32 (5) Vitamin E 35 (6) Vitamin G 35 4. Minerals 36 page a Calcium and Phosphorus 37 (1) Calcium 4O (2) Phosphorus 44 B Sources of Requirements 48 1. Protein 48 a Proteins of Roughage 48 (1) Ray 48 (2) Silage to b Proteins of Cereals 57 (1) Corn ‘ 60 (2) Barley e4 (3) Cats 66 (4) Wheat 70 0 Protein Concentrates 71 (l) Cottonseed Meal 72 (2) Linseed Oil Meal 7e (3) Soybean Oil Meal 76 (4) Corn Gluten Feed 77 (5) Wheat Bran 77 d Protein Content of Feed Used in This Experiment 78 2. Energy 79 3. Vitamins 79 a Vitamin A 7 80 b Vitamin B 84 0 Vitamin C 85 page d Vitamin D 86 0 Vitamin E 87 1 Vitamin G 87 4. Minerals 88 a Calcium 88 b Phosphorus 90 0 Limitation of Ration 93 D. Discussion of Review of Literature 104 III Experimental Work 106 A Object 106 B Plan of Experiment 106 1. Animals 106 2. Management 106 a ‘Rations and Methods of Feeding 106 b Milking 107 0 Bedding 108 d Collection of Data 108 (1) Weight 108 (2) Feed Consumed 108 (3) Samples ' 103 (4) Production 108 (5) Reproduction 108 C Procedure 109 1. Animals 109 2. Season of Year 109 5. Management . 109 IV V p. (N H O h Shelter Exercise Milking Bedding Weight Length of Feeding Period Watering Feeds and Feeding D Experimental Results 1. Butterfat Production 2. Milk Production 3. Fat Corrected Milk 4. Feed Consumption 5. Palatability of the Rations 6. Health of Animals 7. Weight of Animals 8. Discussion of Experimental Results B Summary Bibliography Charts page 109 109 109 110 110 110 110 110 112 112 113 114 114 115 115 116 116 118 119 145 INTRODUCTION Variety in the ration of lactating dairy cows is usual- ly considered necessary in order to insure the presence of all the dietary factors, especially the essential amino acids. The ordinary home grown feeds for dairy cattle in Michi- gan are alfalfa, clover and timothy hays; corn silage, sun- flower silage and roots for succulence; and barley, oats and corn for grain. A home grown ration usually consists of a hay, silage or roots, and one or more of the cereals. Such a ration even when a protein concentrate is added to furnish a sufficient quantity of protein is considered by most in- vestigators to be lacking in the quality of protein necessary to maintain good health, reproduction, and a high level of milk production. Consequently many dairymen purchase a Variety of pro- tein feeds to supplement home grown rations. Milk could be produced more economically if the cheapest protein supple- .ment supplied the essential amino acids. It is the purpose of this investigation to compare a simple rationmconsisting of home grown feeds supplemented with cottonseed meal, with a complex ration consisting of the same home grown feeds supplemented with wheat bran, cottonseed meal, linseed oil meal and gluten feed, for milk production. REVIEW AND DISCUSSION OF LITERATURE The importance of variety in the ration of dairy cows has long been emphasized. The Opinion prevails that a variety of feeds is more likely to contain all the dietary factors than a simple ration. However, simple rations com- posed largely of home-grown feeds are usually less expensive. The prevailing low prices of dairy products and the prospect that they will continue makes it highly desirable that a cheaper ration consisting largely of home-grown feeds, that will be suitable for high milk production and satisfactory reproduction be worked out. Such rations have been consid- ered to lack in some of the essential amino acids, especial- ly when non-legume hays were used in the ration. REQUIREMENT OI PROTEIN II‘RATIOI or DAIRY COW Quality as well as quantity of protein is essential in the dairy cow's ration for satisfactory production and re- production. In 1911 Hart, IcOoIIum, Bteenbook and Humphrey (1) fed dairy cows on restricted rations from.the wheat, corn and cat plants. They found that rations from different plant sources balanced in regard to supply of digestible organic nutrients and production therms were not alike in respect to general vigor, size, and strength of offspring and capacity for milk secretion. Bhrt and KcOollum (2) secured results that are not in hammony with the theory that the failure of swine to grow on corn alone is due entirely to the incomplete nature of its protein content. Hart and Humphrey (o) in 1919 showed that it is im- possible to furnish dairy cows of high milk producing ca- pacity with a protein level of sufficient magnitude or qual- ity to maintain that capacity from a clover, corn silage, cereal grain mixture, the latter being made up of corn, bar- ley, cats or a mixture of the three. Cows of low mammary capacity and large food capacity were kept in nitrogen equilibriumi One animal produced 22.24 pounds of milk daily for 16 weeks and maintained nitrogen equilibrium on such a ration. They concluded that with the present knowledge a safe procedure for maintenance of’high milk production is through the use of a high plane of protein intake which al- though of low relative efficiency should be drawn from.the plant protein concentrates rather than those of animal ori- gin. These same investigators (4) after feeding dairy cows on rations in which the protein was furnished with milk were able to maintain a nitrogen balance with production as high as 36 pounds of milk daily. However, negative balances re- sulted when the protein was derived from.either corn or. wheat grain. The milk protein had an efficiency for milk production and tissue restoration of about 60 per cent; corn so per cent, and wheat 36 per cent. These investigators concluded ”That the quality of the protein is an important factor in maintenance and production and that the synthetic powers of the mammary gland will not compensate for defici- encies in protein structure". They suggest that the effici- eney of a protein depends upon its structure. Prom experiments with rats and monkeysilcCollum, Bim- mcnds and Pits (5) concluded that "railure to maintain a normal state of nutrition on,a diet of corn is due to a poor relationship among the inorganic constituents and to its lack of quantity and quality of protein". Iron other feeding trials these investigators statd that "Complete success in nutrition of rats with strictly vegetarian diets of but three natural food stuffs and the failure attending a wider vari- ety in the feed mixture emphasises the fallacy of the assump- tion that the safest plan to insure perfect nutrition is to include a wide variety in the selection of the constituents of the diet. until definite knowledge is obtained, variety will unquestionably make for safety but will not by any means assure safety and can scarcely secure the optimum results in any considerable per cent of the cases." In a study of simple home-grown rations for dairy cows Bowling (6) found ground oats, alfalfa leaf meal, alfalfa hay and corn silage as efficient in maintaining three high producing cows on a positive nitrogen balance as a more com- plex ration made up of alfalfa hay, corn silage, corn, oats, wheat bran, linseed oil meal and cottonseed meal. Following carefully conducted investigations Nevens (7) showed that there is little if any foundation for the claim that protein of a variety of feeds will be used more effici- ontly than the proteins in'simple mixtures made up of one or two farm grains and a single protein supplement, when good quality roughages and prOperly balanced grain mixtures are used. He suggests, however, that rations be made up of at least four different kinds of feeds. Protein Amino Acids The ability of proteins to maintain body weight, milk production, and satisfactory reproduction depends upon their amino acid content. Osborn and Mendel (8) stated that new tissue involves the synthesis of new protein. Growth will be limited, there- fore, by any factor which prevents this synthesis. The lack of any component amino acid which cannot be manufactured di- rectly in suitable amounts in the body represents such limit- ing factors. This explains why adequate growth has never been obtained with rations which fail to furnish sufficient proportions of certain amino acids such as tryptOphane, ly- sine, or cystine. These investigators stated further (15) that "Obviously the relative value of the different proteins in nutrition is based upon their content of those special amino acids which cannot be synthesized in the animal body and which are indispensable for certain distinct, as yet not clearly defined processes, which are expressed as main- tenance or repair." From experiments with rats Hawk and Bergeim (9) found that at least four amino acids are absolutely essential for normal development. They are lysine, tryptOphane, cystine and tyrosine. Life without these amino acids is impossible. They stated that histidine has been added to this list and proline may be required. Synthesis of unessential amino acids probably takes place in the animal's body. From a survey of experimental work Mathews (10) stated that 'It appears that rats and mice at any rate cannot make sufficient lysine, tryptOphane, cystine and tyrosine to sup- ply their needs and that these amino acids must be present in the diet." Following the feeding of different isolated proteins to rats Osborn and Mendel (11) stated that proteins are called incomplete because they lack one or more of the es- sential amino acids. Hart, Nelson and Pitz (12) in reporting upon experi- ments with rats stated "The evidence makes it very probable that the mammary gland has not the capacity to synthesize the amino acid, lysine. The evidence also supports the view that as far as the proteins are concerned milk secretion, like growth, is ultimately dependent upon the quality and quantity of amino acids ingested in the food." gzgigg, Osborn and Mendel (13) succeeded in.promoting growth in rats at a normal rate when a maintenance ration containing glaidin as the sole protein was supplemented with lysine. They stated"These feeding trials in conjunc- tion with our demonstration of the almost complete cessa- tion of growth on a diet containing only lysine free pro- teins furnished the first and only conclusive demonstration that lysine is indispensable for the function of growth". Other work reported by these investigators (8) (l4) demon- strated that sein of maise as the sole protein can be made adequate for maintenance and even slight growth by additions of both lysine and tryptophane. Failure of animals to grow or even be maintained when sein is the sole form of nitroge- nous food intake for any considerable period has been wide- 1y‘reecgnised. Gliadin protein of wheat, hordein of barley and zein ef'maise were called incomplete proteins by Osborn and Inns del (11) because they lack one or more essential amino acids. lone of them furnish glycocoll or lysine. In experimental work with chickens these investigators (15) found that corn gluten permitted only a very slight growth. This was due to the fact that it contains some maise glutenin, a protein which yields tryptOphane as well as a little lysine. They eonclude that chickens as well as rats require a sufficient amount of lysine in order to make normal growth and that this O ‘ VI A- _ ‘ l f V ' " r e r‘ t r‘ . -_ 7 t I- r ‘ ‘ L' , av ; ,'\ . fl ,\ - - 4 \ : r‘ ~ I“ C . n I .7 ' \ . ‘ ‘7 . ‘V- l‘ ’1 ’fi. ' -r A . I. - /\ fl ' ~ I ' ~ ( l‘ '- s . r , ‘l f L l k a . a F 7 st 0:, a: (V l ‘A ' r I (E r H" nu ~ e . l , r O C ‘ v A f ‘e‘\ . ‘ f 1‘ ' r l' v I I r ' 3. m - 1 l‘ " ; 1..“ \ b ‘ t : b J .L J J N (I '1‘ "‘In 0'!" -“ " § 7 will doubtless be found true for other species. In further experimental work with rate these investigators (16) found that to maintain normal growth 15 per cent of casein was the least that could be fed. lormal growth could be maintained on 12 per cent casein plus lysine equal to two per cent of the casein. lhen less than 12 per cent casein was included in the diet the lysine caused some improvement in growth. Using rats Hawk and Bergeim (9) found lysine to be one of the amino acids absolutely essential for normal develop- ment. Life without this amino acid is impossible» Mathews (10) concluded that rats and mice at any rate cannot synthesise sufficient lysine to supply their needs but that it must be present in the diet. In a feeding trial with two lots of chickens on a high and low lysine ration Buckner, Hollan and Kastle (17) found that the high lysine ration gave normal growth while the low lysine ration.materially stunted their growth. Ceiling (18) following an experiment with mice concluded that "Lysine does not appear to be necessary for the mainte- nance of adult 'mice. " Lewis and Root (19) found that gliadin comprising 18 per cent of the diet was inadequate for normal growth of the white rat. It did, however, permit maintenance or slow growth. lhen lysine was added in amounts equivalent to three per cent of the protein in the diet without further altera- tions it renders the diet adequate for normal growth. These results agree with the work of Osborn and Mendel. Neither dl-ncr d-nor-leucine is able to supply the deficiency of a gliadin diet as does lysine. Bor-leucine replaced by lysine insures normal growth. No evidence was found that the white rat can substitute nor-leucine for lysine in the synthesis of its body protein for growth. Bart, Ielson, and Pits (12) stated that “The evidence f presented in this paper makes it very probable that the mem- msry gland has not the capacity to synthesise the amino acid lysine". On a lysine free diet young rats were born but were not successfully nursed. Trntoph_e_._ne Ackrcyd and Hcpkins (20) found that when tryp- tOphane was removed from the complete amino acid diet of rate they not only discontinued growth but lost in weight. Iheeler (21) discovered that mice fed sein lost on the average one-third of their weight in 25 days while two mice which had an addition of tryptOphane equal to three per cent of coin fed lost only about one-fifth’of their original weight by the fifteenth day, thus showing the effect of the small amount of tryptophane on body maintenance. 'illcock and Hepkins (22) observed tint sein is the only nitrogenous constituent unable to maintain growth in young mice. The addition of tryptophane. an amino acid absent from the decompOsition products of sein to this dietary odid not make it capable of maintaining growth. It did, however, greatly prolong the survival period and materially aided the well being of the animals. Hawk and Bergeim (9) using rats found that tryptOphane was absolutely essential for normal develOpment. Without it life was impossible. Mathews (10) concluded that rats and mice at any rate cannot synthesize sufficient tryptOphane to supply their needs but that this amino acid must be present in the diet. Osborn and Mendel (8) (13) found that tryptOphane can £££_be synthesized in the animal's body. They stated "The need for tryptOphane and lysine is governed by the 'Law of Iinimum'." The rate of growth increases with increased amounts of these amino acids furnished by the food until the normal rate is attained. A certain minimum amount of tryptOphane is essential for maintenance without growth. Zein can be made adequate for maintenance and even slight growth by additions of both lysine and tryptOphane. Zein failed to promote growth satisfactorily even with the addi- tion of plenty of tryptOphane, unless two per cent or more lysine was furnished with the protein. This emphasizes the indispensability of tryptOphane for maintenance and lysine for growth. Berg and Rose (23) found that tryptOphane when admin- istered to tryptOphane deficient basal diets exerted a marked influence upon the rate of increase in body weight thus sup- 10 porting growth as well as maintenance. Feeding half daily allowances each 12 hours induced better growth than when the total daily allowance was administered at one time. More frequent feeding appeared to exert little if any influence. These same investigators (24) later found that acetyltrypto- phane and tryptOphane ethyl ester hydrochlorde were utilized for growth Just as satisfactorily as free tryptOphane. Thus these tryptOphane derivatives are used for growth in place of tryptophane. Also 3-indolepyruvic acid added to trypto- phane deficient diets leads to an immediate resumption of growth in rats at a rate quite comparable to that induced by the equivalent quantity of tryptOphane. This synthetic product is probably substituted for tryptOphane by being transformed into the amino acid. This they stated "Is proof of replacement of an indispensable amino acid by a synthetic compound." Cystine Osborn and Mendel (8) stated that adequate growth has never been obtained with rations which failed to furnish sufficient proportions of the amino acid cystine. They also found (16) that the minimum amount of casein which the food must contain in order to promote normal growth was 15 per cent. Twelve per cent casein failed to support normal growth until cystine equal to three per cent of the casein was added. These same investigators (27) following work with rats stated (“The addition of cystine equiValent to three per cent of the casein used effected considerable economy in the availability 11 of this protein." By replacing cystine with alanine they failed to bring about any nutritive advantages. Hawk and Bergeim (9) found with rats that cystine was absolutely essential for normal development. In fact life without this amino acid was impossible. Mathews (10) stated "It appears from these experiments that rats and mice at any rate cannot make sufficient cystine to supply their needs but that this amino acid must be pres- ent in the diet." Lewis (25) concluded that the addition of small amounts of cystine to the diet of dogs on a low protein diet diminished the loss of nitrogen from the body and favorably influenced the nitrogen balance. This result was interpreted to be a specific demand for cystine for metabolic purposes since ty- rosine and glycocoll added to the diet under like conditions of experimentation did not diminish the nitrogen loss or in- fluence the condition of nitrogen equilibrium. Muldoon, Shiple and Sherwin (26) found after several trials that the dog was unable to synthesize cystine. Beadles, Braman and Mitchell (28) were able, by adding cystine to a ration whose protein was so low as to be a limiting factor in growth and deficient in this amino acid to increase its value for the promotion of hair growth in the albino rat. Lightbody and Lewis (29) found that the amount of hair was related to the protein content of the diet but under their experimental conditions the demand for protein (and 12 cystine) for the growth of hair appeared to be secondary in importance to the demand for growth of the body with its more essential tissue. Hoods (30) found that rats stunted for eight weeks by the absence of cystine were able upon returning cystine to the ration to resume growth at a rate fully normal for their size and make normal records in reproduction and the rearing of young. The basal ration was whole milk over diluted with starch, minerals and vitamins. Westerman and Rose (31) secured results which they stated showed conclusively that "Neither synthetic dithiodglycollic acid or B-dithiodproipionic acid when fed to rats are capable of serving in the place of cystine and producing growth des- pite the close similarity in chemical structure. This evi- dence also shows that dithiodglycollic acid in the presence of cystine leads to a subnormal growth apparently due to either toxic or in acne other manner exerts an inhibitory influence upon the growth process. B-dithiodiprinionic acid produces little if any effect or influence providing an adequate amount of cystine is present." Lewis and Lewis (32) conducted experiments in which tau- rine and cystinic acid were fed to young white rats on two types of diet in which cystine was the limiting factor. They obtained no evidence showing that either taurine or cystinic acid could replace cystine entirely or in part for the purpose of growth in the absence of an adequate amount of cystine in the diet e 15 Sherman and lbrrill (33) found that cystine is the first limiting amino acid of the protein of cow's milk for the growth of young rats. Oystine was found in experiments with rats by Sure (34) to be the primary growth ltmiting factor of the protein, lactalbumin. The results suggested that protein free milk contains either cystine or organically bound sulphur which the animal organism can transform.into cystine. lhsrman and Wood (55) were able to make determinations of cystine by means of feeding a diet in which cystine was the growth limiting factor. lhen this ration was fed to carefully standardised young rats with or without graded addi- tions of cystine it was found possible to determine a direct linear or arithmetical relationship between the added cystine fed and the added growth thereby induced up to an added gain of 10 grams in an experimental period of six weeks. This induced growth was brought about by graded additions of eye- time from 0.025 to 0.04 per cent with added gains obtained up to 17 grams. . Parallel experiments with graded additions of casein to the same‘basal diet gave correspondingly graded responses ' in growth. lith these results an arithmetical proportion was worked out to interpret the amount of cystine furnished by casein. Results indicate casein contains 1.3 to 2.5 per 14 cent cystine or that three-eighthe to three-fourths total sulphur in casein is cystine or cystine plus other sulphur containing radicals which are interchangeable with cystine in nutrition. This lower limit was higher than the amount obtained by analytical methods. (A diet of cooked lima bean meal supplemented with 0.3 per cent of cystine together with other necessary non-protein dietary ingredients according to rlinks and Johns (36) furn- ished adequate protein for the normal growth of albino rats. A sflmilar diet to which no cystine was added, merely main- tained the weight of the experimental animals. Growth did not occur if the diet cOnsisting of either raw or cooked lima bean meal was not supplemented with cystine although the other non-protein dietary factors were added. Following experiments with rats Haag (37) stated that "There can be no reasonable doubt concerning the effective- ness of cystine in improving the nutritive value of rations in which protein is supplied by alfalfa leaves. These ex- periments are interpreted as demonstrating a deficiency of cystine in the mixed crude protein of alfalfa". In feeding experiments with young rats Rose and Huddle- stun (38) showed that taurine is totally incapable of replac- ing cystine in the diet for the purpose of growth. It is stated by.Mitchell (39) that cystine added to a cystine deficient diet will improve its growth promoting 15 value in animal nutrition. It is convertible into cystine in anabolisma lo evidence was obtained indicating that taurine possesses this prOperty. Ceiling (18) stated, following experimental work with mice, that cystine appealed to be necessary for the mainte- nance of adult mice. gzgosine Diets containing zein as the only nitroge- nous constituent were fOund by Willcock and Hepkins (22) to be unable to maintain growth in young mice. The addition of tyrosine, which is already present in sein, had no effect in maintaining growth or adding to the well being of the animal. It was found by Totani (40) that rate may exhibit al- most normal growth when the supply of tyrosine is diminished to an extremely small amount. These results differ from those of Abderhalden who fed a dog a preparation of the die gestive products of caseinogen freed from tyrosine as com- pletely as possible, that lost weight to the extent of 750 grams in nine days. Loss of weight was almost entirely re- gained when tyrosine was again added to the diet. In feeding experiments conducted by Abderhalden (41) in which a diet low in tyrosine was fed to rate, it was found that for a period of 12 weeks growth was independent of the tyrosine content of the food. 16 Lewis (25) found in feeding trials with dogs that the addition of small amounts of tyrosine added to the low pro- tein diet did not diminish the nitrogen loss or influence the condition of the nitrogenous equilibrium. Tyrosine was found to be the secondary growth limiting factor in the protein lactalbumin by Sure (34). He also found that protein free milk gave qualitative tests for ty- rosine. Mathews (10) stated that it appeared from experiments with rats and mice that these animals at any rate cannot make sufficient tyrosine to supply their needs but that these amino acids must be present in the diet. Using rats Hawk and Bergeim (9) found that tyrosine was one of at least four of the amino acids absolutely essential for normal development. In fact, life without it is impos- sible. Histidine The importance of histidine in the diet of a young rat was demonstrated by Harrow and Sherwin (41a). They found imidazol pipwic acid able to replace histidine to some extent in the diet. However, imidazol lactic acid was much more efficient in this capacity, while imidazol acrylic acid was less so. They found imidazol alone to have no value when used with a histidine free diet. Cox and Rose (42) found upon adding non-amino acids to a ration from which most of the histidine had been removed that some rats failed to inhibit the loss in weight occasioned 17 by deficiency of histidine. The addition, however, of d1-B-4 imidazole lactic acid to this diet caused an immedi- ate resumption of growth at a rate slightly slower than that induced by the equivalent quantities of histidine. This syn- thetic product is capable of serving in place of histidine, probably through being transformed by the cell into the amino acid. This they stated "Is the first successful attempt by growth experiments, to replace an indispensable amino-acid 0f the diet by a non-amino-acid." These investigators (43) concluded from later work that growing animals receiving diets deficient in histidine but adequate in every other respect to meet the nutritive requirements of the organism that neither adenine, guanine, creatinine, creatine, nor a combination of these compounds is capable of functioning in place of the missing amino acid. These results are interpreted as indicate ing that the reaction of purine synthesis from histidine is an irreversible one in the animal organism. Berg, Rose and Marvel (24) reported that 4-imidazole lactic acid induces the growth of rats upon a histidine de- ficient diet. Histidine and Arginine Rats upon arginine-histidine free amino acid mixtures were found by Rose and Coy (44) to be neither able to grow or maintain weight but promptly and con- tinually lost weight. The addition of histidine to such a ration resulted invariably in an immediate resumption of 18 growth at a normal rate. Histidine was thus shown to be an indispensable component of the diet. In contrast to histi- dine the addition of arginine to the deficient diet exerted no influence upon growth even when the quantity added was more than equivalent to the sum of the arginine and histidine pres- ent in the native casein which was used in this diet to furn- ish the nitrogen and which allowed rats to grow to maturity providing the arginine and histidine were not removed, al- though at a rate somewhat slower than normal. It is evident therefore, that arginine and histidine are not mutually inter- changeable in metabolism. These same investigators (45) stated that further experiments with three rats showed the total in- ability of arginine to assume the functions of histidine. In studies made by Ross and Cook (46) of creatine and purine metabolism in growing rats upon diets in which the nitrogen was supplied respectively in the form of casein, completely hydrolized casein from which histidine and argi- nine had been precipitated by the Kossel-Kutscher prOcedure, the diets of whole casein and completely hydrolized casein led to excretion of progressively increasing quantities of total creatinine, allantain and uric acid, which were roughly prOportioned to the increments of the body weight of the animal. On diets of hydrolized casein from which histidine and arginine had been precipitated the output of allantain 19 decreased 40 to 60 per cent. Uric acid excretion also de- creased but the variation from normal values was not quite so great as for allantcin. Total creatinine manifested an increase followed by a decline but did not fall below the level seen on an adequate ration. The effect upon purine metabolism was not attributed solely to loss in weight of rats on deficient diets as in- dicated by experiments in which a deficiency of tryptophane was induced. On rations adequate in every respect except tryptophane content the animal steadily declined in weight but the output of the allantcin and uric acid remained quite constant. The adding of histidine to diets which component hydro- lized casein had been subjected to silver-precipitation, lead to increase in excretion of total creatinine, uric acid, and allantcin until the same as animals on whole case- in. On the contrary the addition of arginine to deficient rations failed to effect the output entirely. Thus, this evidence pointed out that arginine and histidine are not interchangeable in purine metabolism. There was no relationship observed between the argi- nine content cf the diet and total creatinine elimination of urine. This may be due to the fact that none of the diet is completely devoid of arginine. 2O Ackroyd and Hepkins (20) using rats found the removal of arginine and histidine from a diet otherwise made up to meet the amino acid requirement resulted in a sharp decline in weight. The decline in weight after a time became less rapid than in the case of tryptOphane deficiency. There seems to be some adjustment to the lack of arginine and his- tidine. When one of these two amino-acids was present, how- ever, there was no loss in weight such as follows when both are absent, in fact there was maintenance and even slight growth. It appears that the body with some efficiency can utilize one amino acid vicariously for another. Geiling (is) stated that "Arginine and histidine seem to be interchangeable in nutrition. Full grown mice are able to hold their weight when either one of them together with cystine is present in the ration. In the absence of both, loss of weight results."g Zein can be made ideal for growth by adding arginine and histidine in addition to lysine and tryptOphane accord- ing to Osborn and Mendel (8). Other Amino Acids A response to proline was secured by Sure (47) on a six per cent edestin level, in the presence of cystine and lysine in some animals and in the presence of cystine, lysine and arginine in others in feeding trials with rats. The author thus concluded that "Proline is an essential amino acid for growth." 21 Hawk and Bergeim (9) found that glycocoll can be syn- thesized in the animal's body. They stated that "Synthesis of unessential amino acids probably takes place in the ani- mal's body". mathews (10) stated that "Experiments show that at least glycocoll can be synthesized in large amounts in the animal body." Lewis (25) in adding small amounts of tyrosine and gly- cocoll to the diet of dogs on a low protein diet did not diminish the nitrogen loss or influence the condition of nitrogen equilibrium. From the evidence presented in the review of litera- ture it appears that the amino acids, tryptOphane, cystine, tyrosine and histidine, are essential for growth and main- tenance and that lysine is essential for growth. There is some evidence that arginine and proline are essential for maintenance and growth and that arginine may be interchange- able with histidine. 28 Protein Level rollowing three experiments on the food of’maintenance Haecker (148) drew the conclusion that with cows at rest in comfortable stalls a ration containing 0.06 pounds digestible protein per hundredweight of cow would be ample for mainte- nance. Illett, Holdaway and Harris (155) used 24 cows in an experiment to determine the feeding standard for milk produc- tion. They found that each pound of milk required 0.053 pounds of digestible protein and 0.315 therms net energy for its production on a basal ration. 'The addition of more pro- tein to the basal ration slightly increased the digestibility and cows gained in weight but the efficiency of the protein utilization was slightly lower. Using actual digestibility co-efficients and deducting body gains of protein the selected basal ration and basal protein cows produced results closely in accord, being 0.042 pounds and 0.046 pounds of digestible protein per pound of milk. This standard would allow 0.5 pounds of digestible crude protein and 6.0 therms for mainte- nance per 1000 pounds of live weight.‘ A.raticn containing one pound of digestible protein per 1000 pounds live weight was found by Hill, Beach, Borland, washburn and Story (156) to serve the purpose fer not overly heavy milking cows. lhen one and one-half pounds were used there was a certainty of serving the purpose. Two pounds of 23 protein allowed a slight increase in milk and two and one- half pounds were quite unnecessary. Hill (15?) stated that the protein and maintenance re- quirement for 1,000 pound dry-non-pregnant dairy cow was 0.5 pounds true protein or 0.6 pounds digestible crude pron tein and six therms of energy or its equivalent of 0.5 pounds total digestible nutrients. For fetal construction no addi- tional non-nitrogenous nutrients were needed. However, the protein intake requirement was 0.05 to 0.1 pounds in addition to requirements for maintenance and milk production. One and one-half pounds of protein per 1,000 pounds live weight were sufficient for reasonable good milk yield, body maintenance and a healthy full sized calf. The author concluded that during the first two-thirds of the gestation period the ra- tion should contain nutrients for maintenance and milk pro- duction. This would also serve the purpose of fetal construc- tion during this period. The last one-third of the gestation period, when little if any milk is being produced, a mainte- nance ration plus a ration needed for the milk being produced plus twice the total digestible nutrient content of the new 'born calf would meet the requirements. Iorbes and Swift (158) using a group of 45 balanced periods, averaging 18 days, with farrow Holstein Friesian cows in the first half of a lactating period producing an average of 42.6 pounds of milk per day on a plane of feed 24 intake sufficient on the average to maintain slight nitro- gen storage and live weight equilibrium found the average utilisation of feed nitrogen for milk production and body gain was 51.6 per cent : 0.4 per cent and utilization of utilisable nitrogen (feed minus maintenance) was 58 per cent 2 0.5 per cent. Torbes, Tries and Eriss (159) in studying the mainte- nance requirement of cattle for protein as indicated by the fasting katabolism of dry cows found the daily nitrogen excreted in urine during the last four days of a nine day fasting period was 46.5 grams for one cow and 43.6 grams for a second cow per 1000 pounds of live weight. These nitrogen values are equivalent to 0.62 and 0.58 pounds of body weight respectively or 0.6 pounds as an average per 1000 pounds live weight, which figure is identical with Armsby's published estimate of the crude digestible protein maintenance requirement of cattle. It is 0.1 pound less than.lbrrison's Standard (0.7 pounds) which may be considered as providing more liberally for reproduction and other exi- gencies of practice. This may not represent the minimum protein requirement during feeding in which case an abundant supply of non-nitrogenous nutrients may reduce katabolism of protein to an amount less than that during fasting. The figures for protein katabolism.of fasting, therefore, when 25 used as a measure of protein maintenance requirement during feeding must be considered as providing a certain margin of safety. Perkins and Monroe (160) found no marked difference in digestibility of a very low protein ration observed between cows long accustomed to a ration and others recently trans- ferred from a ration containing a liberal supply of protein. From an extensive experiment with 40 cows over a year's time Savage (l6l) in 1930 found a 16 per cent protein grain mixture as efficient for milk and butterfat production as a 20 per cent and a 24 per cent mixture when fed with mixed hay and corn silage. ' The review of literature indicates that 0.6 pounds of digestible protein per 1,000 pounds of live weight is ample for maintenance and 0.05 pounds of digestible protein in addition for each pound of 5.5 per cent milk produced. Energy Haecker (147) found that a standard ration should con- tain 25 pounds of dry matter, 2.5 pounds of digestible pro- tein, 12.5 pounds of carbohydrates and 0.4 pounds ether ex- tract of fat for cows weighing 1,000 pounds in ordinary work- ing condition. From feeding trials carried on later (148) he concluded that with cows at rest in comfortable stalls a ration containing 11.5 pounds of dry matter containing 0.06 26 pounds of digestible protein, 0.6 pounds carbohydrates and 0.01 pounds ether extract per hundredweight of cow would be ample for maintenance. Ellett, Holdaway and Harris (155) found that each pound of milk requires 0.053 pounds of digestible protein and 0.315 therms of net energy for its production on a basal ration equivalent to 0.053 pounds of digestible protein, 0.12 pounds digestible carbohydrates and 0.019 pounds of digestible fat or 0.053 pounds of digestible protein and 0.3 pounds of total digestible nutrients. These amounts gave the most economical results from the standpoint of ef- ficient use of protein, although the cows lost live weight slightly. The addition of more carbohydrates to the basal ration reduced the digestibility though the cows gained in body weight. Therefore, the above amounts of carbohydrates and fat are the maximum to use. Additional protein added to the basal ration slightly increased the digestibility and cows gained in weight but the efficiency of the protein was slightly lower. These results indicated that 0.5 pounds of digestible crude protein and 6.0 therms of energy are necessary for maintenance of a 1,000 pounds of live weight. The maintenance for dry-non-pregnant cows was found by Hill (157) to be 0.5 pounds of true protein or 0.6 pounds of digestible crude protein and six therms of energy or its equivalent, 6.48 pounds total digestible nutrients per 1,000 pounds of live weight. 27 The net energy requirement fer cattle was found by Armsby (152) to be 5.00 therms per 1000 pounds of live weight and 0.238 therms per pound of 3.5 per cent milk produced. The review of literature indicates that approximately 6.00 therms of energy are required for maintenance and 0.23 therms for each pound of 3.5 per cent milk. Vitamin The importance which vitamins play and the problem of supplying them differs with different animals and the types of foods they ordinarily consume. A review of the literature will indicate the possibility of a simple ration furnishing vitamins for dairy cows. Vitamins - General It was concluded by MoOollum and Davis (48) after feed- ing a ration containing protein, carbohydrates, fats and salt that there are certain other unidentified substances indis- pensable for growth and prolonged maintenance. They found that growth could not take place when highly purified casein, dextrin, salt mixture, liberal amounts of water and alcohol soluble accessory were fed. Both water soluble and fat sol- uble accessories must be present before growth can take place. Growth during a period of a few weeks on diets of isolated food stuffs is an indication that both classes of 28 accessories are retained in the lactose and casein as im- purities. A high degree of purity must be attained in order to eliminate these substances. It was stated by Ravens (7) in 1931 that dairy cattle receiving rations containing well cured legume hay in lib- eral amounts with well balanced grain rations are not likely to suffer from deficiencies of vitamins. Pastures and leg- umes are the best source of vitamins. Farm grains and seeds and most milk by-products contain at least moderate amounts of vitamins. There is no known advantage in adding vitamin rich substances to rations for milk production. Studies were made by St. Julian and Heller (49) on the effect of vitamin deficiency upon the co-efficient of diges- tibility of proteins, fat and carbohydrates. This was done by comparing metabolism of animals on a diet deficient in a given vitamin with metabolism of animals on the same diet plus the vitamin. Vitamins A, B, Bg, D and 0 were studied. in case of each of these vitamins the co-efficient of diges- tion of protein, carbohydrates and fat were the same in the animals on deficient rations as in those which received a complete diet. It would appear unlikely, therefore, that the digestive process is effected by the vitamins studied. vitamin A Lindquist (136) stated that vitamin d is neces- sary for growth and prevents xeropthalmia. 29 Studies were made by Jenes, Eckles and Palmer (136) using nine calves, which show that vitamin A is an indie- pensable factor in the diet of calves. The characteristic symptoms of vitamin A deficiency in other species of animals including failure to grow, zerophthalmia, respiratory troubles, diarrhea and death, occur in herbivore as represented by calves. Ihen cod liver oil was added to the vitamin A deficient ration a resumption of growth and a disappearance of symptoms took place. It required less than one per cent of cod liver oil in a ration otherwise practically free of vitamin A to allow calves to grow normally. It was found that vitamin A was present in large amounts in the liver of calves fed normal rations but is absent from the liver of calves fed vitamin A deficient rations. ‘ In feeding a ration devoid of roughage consisting of whole milk, to calves from birth to six months of age, plus a concentrate mixture fed ad libitum and made up of 400 pounds rolled barley, 300 pounds rolled oats, 300 pounds wheat bran, 100 pounds linseed meal and 8 pounds salt, with the roughage replaced by an amount of alfalfa ash equal to that supplied by a normal alfalfa hay ration Mead and gRegan (52) found that calves can be reared to 19 months of age and normal growth secured providing cod liver oil is added to supply vitamin.A. 30 glitamin B Vitamin B, according to Lindquist (51) protects against neuritis and beri-beri. lokles, Williams, Wilbur and Palmer (53) found upon add- ing vitamin B in the form of dried yeast to the ration ordi- narily fed on dairy farms that it did not increase the rate of growth of calves from 20 to 180 days of age. He definite effect was observed on the health of these calves. lhen a dried yeast preparation was added at the rate of 25 grams per pound of milk produced to a ration commonly fed in good dairy herds, Eckles and Williams (54) found it did not increase the milk or fat yield.) Further, no effect could be observed in the condition of the animal or on the appetite. Bechdel, Hckles and Palmer (55) found that calves will grow to maturity and produce normal offspring on a ration that carries insufficient amounts of vitamin B to support growth and general well being in rats. They stated that if calves possess a physiological requirement for vitamin B similar to other animals, the deportment of experimental calves described can be explained only on the basis of vita- min B synthesis by bacteria and other microorganisms in the digestive tract unless further investigation should prove that various species of animals differ materially in vita- min 3 requirement. It was found further that milk produced by cows fed on rations deficient in vitamin B is apparently, but not markedly, reduced in its vitamin 3 content. 31 Investigations by Bechdel, Honeywell, Dutcher and Knut- sen (56) showed that vitamin B complex was produced in the rumen of their experimental cow by bacteria fermentation. These results offer a satisfactory explanation as to why cattle, unlike any other species of animal yet studied, have the ability to grow to maturity, to reproduce normally and to produce milk of normal dietary composition on a ration that carries an insufficient amount of vitamin B complex to support growth and well being in rats. Vitamin G Lindquist (51) stated that water soluble o vita- min prevents scurvy, bone disease, and partial paralysis. It was found by Thurston, Eckles and Palmer (57) that calves do not require vitamin C in quantities that can be measured by the present methods of testing food materials for their antiscorbutic potency by feeding them to guinea pigs. They stated that "Under practical conditions even where very poor feeding practices are followed there is little if any reason to believe the well being of the calf will be af~ fected by a shortage of vitamin C. These same investigators (58) later found vitamin C in the liver of calves fed for one year on a ration capable of producing scurvy in guinea pigs within 30 days. They found that heifers fed from birth on a soorbutic diet secreted appreciable quantities of vitamin C in the milk. The absence of vitamin 0 apparently does not in- 32 interfere with reproduction. It is probably that vitamin C is synthesized within the body of the bovine. Evidence is supplied to indicate that the digestive tract is not con- cerned in this synthesis. Vitamin D It was shown experimentally in 1922 by McCollum Simmonds and Becker (59) that cod liver oil oxidized 12 to 20 hours does not cure xerophthalmia in rats. It does,_how- ever, cause deposition of calcium in the bones of young rats which are suffering from rickets. They concluded that oxi- dation destroys fat-soluble.A without destroying another sub- stance which plays an important role in bone growth. This evidence demonstrates that the power of fate to imitate the healing of rickets depends on the presence in them of a sub- stance which is distinct from fat soluble.A. Thus these ex- periments clearly demonstrate the existence of a fourth vita- min whose specific pr0perty as far as we can tell at present is to regulate the metabolism of the bones. In 1929 Sheehy and Senior (60) added six to eight ounces of cod liver oil daily to the ration of three milking cows which were fed on a winter ration of hay, roots and meal and had reached the 14th, 11th and 19th weeks respectively of their lactation periods. They found that it did not alter the calcium or phosphorus content of the milk produced. Hart, Steenbock, Tuet, and Humphrey (61) found alfalfa hay cured inside no more potent in antirachitic preperties than alfalfa cured under the best sunning conditions in Wis- 53 consin. "All the hays studied possessed measurable anti- rachitic properties, however, none of these hays fed in our ration at a level of about 10 pounds per day were able to maintain calcium equilibrium in a liberally milking cow. " These same investigators found from another experiment (62) that the feeding of one-half pound daily of cod liver oil, potent in vitamin D, showed no favorable influence upon the calcium.assimilation of liberally milking cows. The vitamin D in cod liver oil was poorly absorbed, i: at all, from the intestinal tract. In 1930 Hart, Steenbock, Kline and Humphrey (63) con- ducted an experiment in which irradiated yeast, potent in vitamin D, showed no positive influence in improving the lime assimilation of liberally milking cows receiving alfalfa hay, corn silage, grain and grain by-products although vita- min B was absorbed into the blood as evidenced by the en- richment of the milk in this factor. The composition of the blood in respect to calcium and inorganic phosphorus was not changed during this irradiated yeast feeding period, nor was the per cent of calcium and phosphorus changed in the milk. The milk production was well sustained during eight months of irradiated yeast feeding and there was no indication of disturbance of physiological functions during this period. 1’" 54 Steenbcck, Hart, Hanning and Humphrey (64) increased the antirachitic potency of milk by feeding 50 grams of ir~ radiated yeast to lactating dairy cows. Two hundred grams did not lower the milk production or butter fat contentaitho 10 grams showed some effect on the antirachitic potency of butter fat. They found 180 grams of cod liver produced sim- ilar results to 10 grams of the yeast. ‘ In an experiment in which cows were exposed daily to sunlight or artificially generated ultra violet radiation, Steenbock, Hart, Rising, Hoppert, Basherovand Humphrey (65) found little if any effect on the antirachitic potency of milk. Ho improvement in milk or butter fat secretion was observed. They concluded that, "The superiority of summer produced milk and butter fat must therefore have origin in other factors than sunlight acting directly on the cow.” These investigators also found that direct exposure of goats to the radiation of a quarts mercury vapor lamp in- creased the antirachitic value of its milk very decidedly; Ultimately the goat showed a very decidedly negative calcium balance although at first there was a slight improvement in calcium retention. . Gulickson and Eckles (66) stated that 'So far as could be measured by general observations, weights and rate of skeletal growth, the absence of sunlight was without effect upon calves kept in darkness from the age of one week to two years. Hormel reproduction also occurred. 35 Results secured by Huffman (67) indicate that calves require vitamin D. Calves fed a basal ration low in this vitamin and kept from sunlight developed rickets, while calves fed the same ration and turned into an Open lot where they were exposed to the sun were normal. Calves fed the same ration plus cod liver oil and kept out of the sunlight did not manifest symptoms of rickets, thus indicating that calves are able to use vitamin D in cod liver oil. The addi- tion of two pounds of sun cured timothy hay per day prevented the onset of rickets in calves fed-this basal rachitic ration and kept away from sunshine. "It is likely", the author concluded, "that such hay is the principle source of vitamin D for dairy cattle during the winter months. These results also explain why calves under ordinary farm conditions fail to show rickets during winter. Calves eat hay at an early age which probably furn- ishes sufficient vitamin D for normal growth and for pre- vention of rickets." Vitamin E The vitamin E requirement of cattle is not known altho several investigators have demonstrated that this vitamin is necessary for normal reproduction in rats. Vitamin G Hussemann and Hetler (69) found that to produce successful lactations in rats both vitamins B and G must be present in the diet. It may be that there is a definite quantitative relationship which exists between these two 56 vitamins. They found that either vitamin D or G in quanti- ties above and added to the maintenance level of the vitamin B complex yields more successful lactation. In view of the fact that as successful results followed the use of auto- claved yeast, a source of vitamin B free from vitamin G, as were obtained when tikitiki a source of vitamin B also con- taining vitamin G was used in addition to the maintenance level of yeast,it seems possible that the added vitamin G is the more important for successful lactation. .The review of literature on the vitamin requirement for the dairy cow indicates that vitamin A and D are neces- sary for satisfactory growth; that vitamin B'is synthesized in the rwmen and 0 in the body. Little is known regarding the requirement of vitamins E and G by the dairy cow. Mineral A large number of experiments have been conducted in recent years on the mineral requirement of dairy cattle and the factors which influence mineral retention. The review of literature will cover only calcium and phosphorus although . it is known that there are other minerals which are needed. However, they are provided in most cases in the normal ration by adding salt. Iodine is also needed where goiter is prev- ‘1 .nt e 37 Calcium.and Phosphorus It was found by McCollum and Davis (70) that with other factors adequate, young rate can grow normally and remain in lapparently good health on diets whose base content varies widely in amount. The growth and well-being was not markedly interfered with on highly acid rations. However, no repro- duction took place which shows that the ration was not suf- ficiently adequate. leigs and Woodward (71) concluded that ordinary rations are more likely to be deficient in one or both of the prin- oipal bone building elements than any other constituents. Cows fed for several years on ordinary rations with little or no additional pasture may result in milk yields being reduced below optimum. This may be corrected by feeding legume hay plus grain with a high phosphorus content and three to four times the protein and two to three times the total nutrients needed for maintenance during two months' dry period. Becker and lokles (73) found that milk remained normal in calcium and phosphorus even under conditions of osteoma- lacia so severe as to show marked symptoms in the animal re- sulting from.an extreme and long continued shortage of phos- phorus. . Prom an experiment to determine the value of a mineral supplement of 80 per cent dicalcium phosphate plus 20 per cent carbonate for dairy cows fed on a ration supposedly de- 38 ficient in lime, Lindsey and Archibald (731)(74) found that the cows with one exception maintained their general condi- tion. The cows on the mineral supplement, however, remained in slightly better condition and made considerable gain in weight while those not on the mineral showed little change. The mineral supplement showed little effect on the growth of young cows and heifers. There was no effect on quality or quantity of milk. Prom the standpoint of reproduction neither group had serious troubles. The mineral supplement group was slightly nearer normal and had somewhat better calves. Hens of these differences were sufficiently strik- ing to warrant a general recommendation of this mineral. They stated, "With cows producing 5000 to 8000 pounds of milk, fed normally good quality roughage, the need of’min- eral supplement was not indicated. The average cow has a considerable margin of safety." "For heavy producers, lOpOO pounds, it is probably good insurance to supply lime and phosphorus, but the efficiency of such a practice is by no means well established.” The same cows used in this experi- ment produced 12000 pounds of milk on a low ash ration. Tour and one-half years of previous work indicated that the benefits derived frmm adding steamed bone meal to the ration of dairy cows was very slight. It was found by Turner and Hartman (75) that two cows receiving an excellent dry ration consisting of well cured 39 alfalfa hay, mangel beats, and a good grain mixture (calci- um and phosphorus ratio 1.09/1.19) and yielding 27 and 22 kilograms of milk daily remained in prevailingly negative calcium and phosphorus balance throughout a period of seven weeks. Huffman, Robinson and Winter (76) found in a series of calcium and phosphorus balances on cows when in heavy, medium and low milk production and when dry that a ration of timothy hay, corn silage, and grain furnished sufficient calcium and phosphorus for the production of at least 10,000 pounds of milk per year. During the height of production the animals were frequently in negative balance but subsequently positive balances made up the loss. A positive calcium and phosphorus balance was obtained in heavy milking cows when this ration was supplemented with bone flour. A cow milking 80 pounds of milk a day showed positive calcium and phosphorus balances. There was a tendency for cows to utilize both calcium and phosphorus more efficiently when in high production than when in low production or when dry. The total intake of calcium and phosphorus was considered to have a greater significance in the utilization than the calcium phosphorus ratio. Hllenberger, Hewlander and Jones (77) fed a ration con- sisting of timothy hay, corn silage and a good grain mixture during the barn feeding period with fresh pasture clippings 40 being substituted for silage and most of the hay during the usual pasture season to which was added in three trials both steamed bone meal and ground limestone as mineral sup- plements. They found that all cows ended their trials with positive balances. When the mineral supplements were fed the negative periods were noticeably shortened. The nega- tive balances appeared to be normal during the early part of the lactation period and to be compensated by rapid stor- age as lactation and gestation periods progressed. The cows in this experiment produced from approximately 10,000 to 18,000 pounds of milk yearly. Calcium On a ration of alfalfa, silage and grain Huffman, Robinson and Winter (76) obtained positive calcium balance in heavy milking cows. They found the low calcium ration was utilized more efficiently than the high. Meigs (72) stated following his experimental work on the mineral requirement of dairy cows that, "There is every reason to believe that stall fed cows can be kept in calcium equilibrium only by feeding large quantities of roughage high in calcium as alfalfa." There is no doubt that mineral deficiencies play an important practical part in the feeding of dairy cows as practiced in many parts of the country when fed dry feed and silage. He stated further that "Deficien- cies of phosphorus are less common than calcium." Less apt to have a deficiency of calcium if cows are on pasture. He further questioned the value of mineral supplements. 41 The adding of a mineral supplement furnishing lime to the ration of cows, sheep and horses when the forage fed is grown in acid soils and of a non-legume type was recommended by Hart, Steenbock and Morrison (78). Salmon and Eaton (81) secured data which showed that two ounces of steamed bone meal per animal per day did not have a decided effect on the growth in weight or height of three Jerseys and one Holstein. The character of the growth was very similar to that of comparable heifers that did not receive any mineral supplement except common salt. The ra- tion used was low in calcium. Mbnroe and Perkins (82) conducted eight balances of phosphorus, calcium, magnesium and nitrogen on four cows that had always been restricted to dry feed and on four cows from the regular herd pastured the previous summer. The ' rations used were identical. A 30 pound level of daily milk production was secured. The calcium balance formed the chief difference between the dry feed and the regular herd group. Taking 36 days as a unit all these balances were negative. The negative balances of the regular dairy herd amounting to approximately 8.5 grams daily, which were more than double the losses sustained by the dry fed cows. Reed and Huffman (83) stated "Cows producing less than 10,000 pounds of milk a year, receiving rations containing a high quality hay do not need additional calcium." 42 It was found by Miller (84) in balanceiexperiments of calcium and phosphorus with liberally milking dairy cows that there was a better assimilation of calcium when clover hay instead of timothy was fed as a part of the ration which included corn silage and a grain mixture. There was, however, little variation in the calcium and phosphorus content of the milk. It is stated by Scott (85) that "Many Montana forage crops while plentifully supplied with calcium are deficient in phosphorus." following experimental work on the assimilation of cal- cium fed as calcium gluconate, Turner, Kane, Hale and Wise- man (86) stated "A supplement of calcium gluconate was of little value in improving the calcium and phosphorus balance of cows giving 19 to 21 kilograms of milk daily. A supplement (of limestone also gave inconclusive results." Pour cows were maintained under herd conditions on a ration of timothy hey, a grain mixture of corn meal 30 pounds, wheat bran 20 pounds, cottonseed meal 25 pounds, linseed oil, meal 25 pounds and salt one pound, and corn silage for a period of 14 to 32 months by Hartman and Meigs (87). They found that the relative amount of ash, calcium, phosphorus, nitrogen and organic matter in cows' bones were little if at all altered by long periods on rations low in calcium.even when a considerable amount of milk is given in such periods. This treatment reduced from 10 to 20 per cent the total weight 43 of the bones and therefore the amount of calcium and phos- phorus in the body. The results indicate that even on a mediocre roughage the calcium assimilation tends to be some- what higher in long periods under natural conditions than shown by most balanced experiments. These results also in- dicate that in case of good cows it may be much higher than shown by most balanced experiments. Ho consistent and favorable influence on calcium assim- ilation in dairy cows was found by Hart, Steenbock and Kline (88) through the daily addition of three pounds of cirelose glucose to a standard ration of hay, silage, cereal grains and cereal grain concentrates. The daily ingestion of 115 to 230 cc. of 40 per cent hydrochloric acid increased the calcium excretion in urine with a greater net loss of cal- cium to the animal than when no acid was fed. The calcium absorption from the intestine was slightly improved through the use of mineral acids. What factors in green plant tissue operate in securing for the cow a better utilization of the calcium in the green plant tissue or added calcium salts was not solved by the technique used in the above experiment. The causes of rickets or disease of the bone according to Huffman (67) are low calcium, low phosphorus, imprOper relation of calcium and phosphorus, and deficiency of vita- min D in the ration, or insufficient amounts of ultra violet light. 44 Calcium content of feeds by Forbes, Boyle and Mens- ching (163) expressed in parts per 100 of dry matter. Barley 0 .043' Oats ' 0.112 Wheat bran 0.139 Cottonseed meal 0.291 Linseed oil meal 0.403 Corn gluten meal Mixed hay (timothy) 0.192 Sunflower silage 'prressed by Sherman (164) in percentage of edible portion. The review of literature indicates that cattle require a certain amount of calcium for satisfactory growth, repro- duction and milk production. Phosphorus Theiler, Green and Du Toit (155) found that in certain areas phosphorus is a limiting factor in the growth of young stock, in the condition of older cattle and in the milk yield of cows. The demands for phosphorus are least for mere maintenance, intermediate for growth, and highest for milk production. Bran is useful for dairy stock or high grade animals receiving supplementary rations in the ordi- nary course of events. These authors concluded, "In all areas where soil and pasture are known to be deficient in phosphorus it is profitable to feed bone meal to practically 45 all stock for the sake of improving conditions and facili- tating rapid growth. For cattle it is particularly advisa- ble since two important diseases, lamsiekte and styfsiekte, can be prevented by liberal bone meal feeding. When insur- ance against disease, increased beef production, increased milk yield and more rapid growth of young cattle are all taken into consideration, it will be found that any expendi- ture on bone meal is repaid many times over.” leigs (72) stated in 1923 that "Deficiencies of phos- phorus are less common than a calcium deficiency". Following experimental work conducted by Hart, Steen- book and Morrison (78) they stated "Phosphorus added as sodi- um phosphate to the ration of a dairy cow during her dry period has been found to increase her milk flow the follow- ing lactation period." Eckles, Becker and Palmer (79) stated "If the dry matter of food contains less than 0.2 per cent phosphorus it is classed as phosphorus deficient and more than 0.5 per cent is classed as phosphorus rich. 0n grass pastures with the presence of vitamin D and sunlight, cows may get along on less than this amount although it is not possible to demon- strate the effect of sunlight in the case of cattle." He found that poor roughage and grain containing only moderate amounts of phosphorus will not furnish sufficient amounts for dairy cattle. There is some relationship between the . a J . . a we . .4 . . . . 1 a n a a L . a s, , . e . . . .\ . .- ..e . — c , . e . . u a. . n e L . _ - 4 w,. .- _ . O A . . . ,1 .. . . w . , Le . ,. a v w .. e. . . e n _ e n . . x _, . . . e . _ . v v, . . e _ . U r v . I v ' i (Q . _ . . e a . .w r . , a, a a e , v e . U I . ii a . . m . § I . . . v. . d - r . . . O . . _ e e 1m . _ . a r 0.. a . . A l _ 46 phosphorus and calcium. Rations deficient in calcium may result in phosphorus starvation even when there is enough phosphorus in the ration. Experiments conducted in 1922 by Monroe (80) showed . that the narrow ration would permit a greater phosphorus retention than a wide ration. In a calcium and phosphorus experiment with regular herd cows pastured the previous year and dry fed cows, menroe and Perkins (82) found the regular herd cows retained only 0.9 grams and 1.4 grams phosphorus daily while dry fed cows retained 3.9 and 4.5 grams daily. The type of water used had no apparent effect. Reed and Huffman (83) stated, "Phosphorus is the mineral element most likely to be deficient in the ration of dairy cattle.“ Miller (84) found that a better assimilation of phos- phorus occurred when more ample provision was made for the element in the grain mixture. The percentage of phosphorus in the milk seemed to increase slightly in response to an increase in the supply in the feed. Hart,_Beach, Delwiche and Bailey (89a) reported Pica, (depraved appetite), which they stated is probably due to low phosphorus roughage and to grazing on pasture low in phosphorus. Six cows suffering from this disease were fed the following two rations with and without cod liver oil: alfalfa hay, corn silage, 35 pounds yellow corn, 25 47 pounds wheat bran, 5 pounds of oil meal and salt; mixed hay, corn silagennd ”a grain mixture of 45 pounds ground cats, 50 pounds yellow corn, and 5 pounds steamed bone meal plus salt. It was found that the rations were equally effective in cor- recting the phosphorus deficiency and that the cod liver oil did not appear to improve the ration. Becker and Bckles (73) stated that "Data indicate that a shortage of phosphorus in the ration over a long period of time may become the limiting factor in milk production." It was found by Scott (85) that many Montana forage crcps while plentifully supplied with calcium are deficient in phosphorus. This phosphorus deficiency results in cal- cium excess when forages are fed to animals and this is physiologically detrimental to cattle, giving rise to vari- ous mineral-deficiency disorders. Phosphorus content of feeds by Forbes, Beagle and Mens- . ching (163) expressed in parts per 100 of dry matter. Barley 0.400‘ Oats 0.434 lheat bran 1.233 Cottonseed meal 1.479 Linseed oil meal 0.786 Corn g1uten.meal 'Mixed hay (timothy) 0.123 Sunflower silage slxpressed by Sherman (164) in percentage of edible portion. 48 The review of literature indicates that cattle require a certain amount of phosphorus for satisfactory growth, re~ production and milk production. ' SOURCES OF REQUIREXEETS Protein The discussion of the literature of protein require- ments brought out the fact that certain proteins are essen- tial for maintenance, growth and milk production in animals. Some of the sources of these proteins for dairy cattle are cited. Proteins of Roughage It is stated by Krauss (89) that dairy rations made up of hay,si1age and grain contain relatively large amounts of non-protein nitrogen. This nitrogen is apparently useful in meeting a part of the protein requirement of a cow in milk. Larsen, Wright, Jones, Hoover and Johnson (90) stated in 1920 that there is a possibility of one protein under- going changes to supply entirely or in part the substances ordinarily furnished by another form of protein although it is doubtful if one protein can replace another entirely. H31 It was found by Hart, Humphrey and Morrison (61a)