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UBC Theses and Dissertations

Growth - with particular reference to it's assessment in beef cattle production Williams, Charles Melville 1952

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GROWTH - WITH PARTICULAR REFERENCE TO IT'S ASSESSMENT IN BEEF CATTLE PRODUCTION by CHARLES MELVILLE WILLIAMS A t h e s i s submitted i n p a r t i a l . f u l f i l m e n t of the requirements f o r the degree of Master of Science i n A g r i c u l t u r e i n the Department of Animal Husbandry We accept t h i s t h e s i s as conforming to the standard r e q u i r e d from candidates f o r the degree of MASTER OF SCIENCE IN AGRICULTURE Members of the Department The U n i v e r s i t y of B r i t i s h Columbia August, 1952 A B S T R A C T This t h e s i s i s the study of the l i t e r a t u r e p e r t i n e n t to the assessment of growth i n a d d i t i o n to the a n a l y s i s of growth data obtained from the Albino Rat, Yorkshire Swine, Black- T a i l Deer and a group, of ten Hereford B u l l s . I t has been conclud ed that animals grow at a constant percentage r a t e r e l a t i v e to body weight over each d i s t i n c t p o r t i o n of t h e i r growth curve.' A s i g n i f i c a n t e r r o r i n the expression of r a t e of gain i s introduced i f animals growth r a t e i s c a l c u l a t e d over any but an Instantan eous p e r i o d . The l a t t e r i s p o s s i b l e because growth of an animal body i s d i r e c t l y p r o p o r t i o n a l to the protoplasmic mass, a f i r s t order r e a c t i o n and as such i s exponential and when the expression i s i n t e g r a t e d , the slope of the' r e g r e s s i o n l i n e , l o g arithm of body weight on time i s provided over the period when r e l a t i v e growth r a t e i s constant. From the r e s u l t s of r a t i o n v a r i a t i o n s with male Wistar r a t s i t was concluded that upon r e t u r n i n g to ad l i b i t u m feeding they w i l l grow at the same r e l a t i v e r a t e as t h e i r c o n t r o l s despite t h i r t y per cent r e d u c t i o n below ad l i b i t u m i n t a k e ;over periods up to two t h i r d s of the b i r t h to sexual maturity phase. The e x t r a p o l a t i o n i s made that beef b u l l calves proceeding from va r y i n g environments normally, experienced on pure- breeding establishments w i l l not.provide biased data when placed on a t e s t r a t i o n and allowed a per i o d f o r the rumen m i c r o f l o r a to become adjusted to the new r a t i o n . Acknowledgement The w r i t e r wishes to thank Professor H. M. King, Head of the Department of Animal Husbandry f o r h i s generous permission to c a r r y out t h i s study and f o r the p r o v i s i o n of the f a c i l i t i e s used. "Sincere g r a t i t u d e i s expressed to Dr. A. J . Wood, Associate Professor i n the Department of Animal Husbandry f o r h i s u n t i r i n g i n t e r e s t and e n t h u s i a s t i c d i r e c t i o n of the execution of t h i s p r o j e c t . The w r i t e r a l s o wishes to acknowledge the co operation received from Mr. H. Doornenbal, Mr. J . P h i l l i p s and Mr. A. Wandefrash who c o n t r i b u t e d to t h i s study. Also Mr. F. Smith and Mr. D. Waldern f o r t h e i r i n t e r e s t and h e l p f u l suggestions. Table of Contents Page I. Introduction 1 I I . Experimental 6 A. Beef B u l l Research Project... 6 (1) Review of Literature 7 (2) Comparison of Direct Methods of Performance Testing... 8 (3) Relative Importance of Conformation 18 (4) Genetic Considerations 20 (5) Rate and E f f i c i e n c y of Gain 24 (6) Proceedures 29 (a) Rationing of Test Animals 29 (b) Weighing Proceedure 37 (7) Results and Discussion 41 B. Wistar Rat Experiment..... 80 (1) Introduction 80 (2) Materials and Method . ...:;81 (3) Results and Discussion $2 I I I . Conclusion and Summary 92 IV. Appendices A. Wistar Rat Body Weight and Feed Consumption Data 95 (a) B i r t h to Weaning. 96 (b) Weaning to 200 grams . . . . 1 0 5 B. Bibliography 141 L i s t of Figures Page F i g u r e 1 Improvement of Growth of Range C a t t l e by Environment and S e l e c t i o n Pressures.... 5 F i g u r e 2 , T y p i c a l Growth of Beef C a t t l e under Varying Environments 5 F i g u r e 3 P a r t i t i o n i n g of Blood N u t r i e n t s 31 F i g u r e 4 P a r t i t i o n i n g of Blood N u t r i e n t s 32 F i g u r e 5 Growth P a t t e r n of T y p i c a l Albino Rats 47 Fig u r e 6 Growth P a t t e r n of York s h i r e Swine 49 Figur e 7 Growth P a t t e r n of B l a c k - T a i l Deer 51 F i g u r e 8-17 Growth P a t t e r n of Hereford B u l l s 53-62 F i g u r e l 8 - 2 0 Growth P a t t e r n of Experimental Wistar Rats 83-85 1 I I n t r o d u c t i o n Growth may be defined as any p r o g r e s s i v e a l t e r a t i o n of a u n i t or group of u n i t s . I n the c e l l u l a r sense i t may i n v o l v e changes i n mass, volume, number or q u a l i t y and the degree of a l t e r a t i o n may be defined i n d e s c r i p t i v e or absolute terms. As i n d i c a t e d by the t i t l e , t h i s t h e s i s w i l l attempt to evaluate the methods used i n assessing p r o g r e s s i v e changes of the beef animal and to expose t h e i r i m p l i c a t i o n s and a p p l i  c a t i ons to p r a c t i c a l beef production. The study may be j u s t i f i e d on the grounds that beef production has become an i n t e n s i v e husbandry w i t h narrowing margins of p r o f i t and l a r g e c a p i t a l investments. As a r e s u l t i t i s imperative that the breeding beef animals be those that w i l l produce progeny y i e l d i n g a marketable carcass i n the s h o r t e s t time w i t h the highest feed e f f i c i e n c y . To achieve t h i s end an accurate, q u a n t i t a t i v e method of i d e n t i f y i n g such animals i s r e q u i r e d . 2 Any e f f o r t directed at the adjustment of a product destined for the consuming public must f i r s t of a l l comply with popular demands as far as possible. I t i s true that public opinion may be conditioned to a limited extent, but as i s often stated, "The man who pays the piper c a l l s the tune," and such i s the case with meat products. A represent ative of the meat packing industry once categorized the buyers of meat as those that: (1) Prefer lean meat. (2) Lack money to buy fin i s h e d meat. (3) Compensate with a s l i g h t l y greater price and a moderate degree of f i n i s h . (4) Prefer to have highly finished meat at any p r i c e . The t h i r d category accounts for the major portion of the buying public. (Watkins, 1936) Associated with the qua l i t y of meat i s the growing demand for the smaller cuts of meat a l l of which obliges the producer to provide an 800 - 1000 pound animal, carrying a moderate degree of f i n i s h . This must serve as the goal unless s u f f i c i e n t evidence indicates that i t i s an impractical target. 3 Present P o s i t i o n : - Beef c a t t l e as they e x i s t to-day are the r e s u l t of some 200 years of s e l e c t i n g f o r parents those i n d i v i d u a l s i n the p o p u l a t i o n most n e a r l y meeting a standard v i s u a l i z e d by such e a r l y breeders as Bake-well'or Cruickshank and more r e c e n t l y i d e a l i z e d by l i v e s t o c k e x h i b i t i o n s . The wisdom of t h i s procedure i s born out when i t i s considered how much more d e s i r a b l e from the stand-point of an e d i b l e carcass the beef animal i s to-day as compared w i t h the work oxen of the type from which the present breeds arose. Just how much of the improvement can be c r e d i t e d to a c t u a l a l t e r  a t i o n of the genotype and how much has been brought about by improved methods of feeding and management i s debatable but undoubtedly both f a c t o r s have played major r o l e s . As i n d i c a t e d by Figure 2, the normal growth p a t t e r n of-the modern beef animal i s one g r e a t l y confused by the environ ment which p r e v a i l s during i t s production. The growth potent i a l now a v a i l a b l e to the feeder of c a t t l e i s only approximated. As an example the normal growth of Texas range c a t t l e shows an annual depression when feed becomes l i m i t i n g w i t h the r e s u l t that they reach a body weight of 800pounds at 2-J years of age. (Lush, 1930). This obviously i s not a measure of t h e i r growth p o t e n t i a l since others of the same breeding can a t t a i n a 1000 pound market weight i n 16 months. 4 The l i t e r a t u r e contains many examples i l l u s t r a t i n g the growth r a t e of f u l l fed beef animals which a f f o r d s an i n d i c a t i o n of t h e i r mean inherent a b i l i t y to grow. This a b i l i t y appears to be the attainment of a l i v e weight of 1000 pounds at 16 months of age under favourable c o n d i t i o n s . (Moulton, 1923) The lower curve of Figu r e 1 i s t y p i c a l of the growth made by range animals. I t may be no.ted that the body weight remains s t a t i o n a r y or decreases .during the winter p e r i o d s . The lower side of the shaded s e c t i o n approximates the mean growth p o t e n t i a l of beef c a t t l e under favourable c o n d i t i o n s . This suggests that the area between the two curves represents the improvement that may be a n t i c i p a t e d by improved feeding and management. The upper curve of the shaded s e c t i o n represents the growth p o t e n t i a l which e x i s t s i n c e r t a i n breeding anin:als of our present herds when n u t r i t i o n and management procedures:; do not l i m i t growth r a t e . ( G i l l i a m County, 1950-51, 1951-52) ( G i i i l b e r t 1950) This curve r e q u i r e s an animal to weigh 1000 pounds at an age of 12 months. The shaded area t h e r e f o r e represents the improvement which may be made by s e l e c t i o n i f the c h a r a c t e r i s t i c i s not r e c e i v i n g a negative s e l e c t i o n pressure due to gene li n k a g e w i t h some c h a r a c t e r i s t i c normally c u l l e d from the p o p u l a t i o n . BIRTH 12 24 AGE IN MONTHS 36 48 F * * A Y E * IMPROVEMENT OF GROWTH OF RANGE CATTLE BY ENVIRONMENT AND SELECTION PREJ & & Brabnatt- Lu4h, 1930} 4 C o w s , b e r t . 1952J C a t t l e , BIRTH 1Z 2 4 36 48 AGE IN MONTHS TYPICAL GROWTH OF B E E F CATTLE UNDER VARYING ENVIRONMENTS 6 II Experimental A . Beef B u l l Research Project , The Hereford B u l l Research Project was i n i t i a t e d at the University of B r i t i s h Columhia, i n November, of 195l } i n response to the wide interest i n performance testing of beef c a t t l e shown by the ranchers and technical a g r i c u l t u r i s t s of B r i t i s h Columbia. The objects of the project as l i s t e d i n the o r i g i n a l prospectus are as follows: (1) To ascertain i f possible the controllable factors which might influence the rate and e f f i c i e n c y of gain of twelve purebred beef b u l l s . (2 ) To establish a s a t i s f a c t o r y procedure for such a program. (3) To determine under B r i t i s h Columbia conditions, the f e a s i b i l i t y of operating a Beef B u l l Testing Program. From the l i t e r a t u r e i t appears that performance t e s t  ing of beef c a t t l e i s not a new idea and has only been delayed i n becoming a general policy by the. technical d i f f i c u l t i e s of developing quantitative measures of beef production which could be used on large numbers of prospective breeding animals. Most of the research to date has followed the a. p o s t e r i o r i type reasoning whereby the re s u l t s of extensive feeding t r i a l s are treated s t a t i s t i c a l l y so that there i s now amassed large amounts of data which w i l l serve a purpose i n d i r e c t i n g the more fundamental studies. I t has been f e l t that this small scale preliminary experimental investigation, with a review of l i t e r a t u r e would be desira-bilee as a foundation for further studies. ( 1 ) Review of Literature There i s widespread d i s s a t i s f a c t i o n among li v e s t o c k groups with the use of v i s u a l evaluation as the sole c r i t e r i a of the breeding worth of meat producing animals. Large d i s  crepancies have been noted from time to time between the standards required i n the show-ring and those which best meet the market and feed l o t requirements. Stothart ( 1 9 5 2 ) presents the r i d i c u l o u s s i t u a t i o n of the f a i l u r e of a large percentage of the ribbon winners i n the sow classes at the Royal Winter F a i r , Toronto, to meet the requirements of the Advanced Registry of Swine. 8 An e d i t o r i a l appearing i n the Farmer and Stockbreeder (May 6-7, 1952), i n d i c a t e s the s i t u a t i o n at the S m i t h f i e l d Show. ...the 117 c a t t l e that were auctioned averaged 802 pounds per carcase. The 41 entered f o r carcase competition averaged 641 pounds per carcase. The 274 l i v e sheep and lambs averaged 80 pounds and 97 sheep entered f o r carcase competition averaged 64 pounds per carcase.... This b i g d i f f e r e n c e i n weight i s made up mostly of superfluous f a t . The f a t stock show e x h i b i t s and e n t r i e s f o r carcase competition should be much nearer each other i n weight and conform a t i o n , because the u l t i m a t e end of a l l f a t stock •is d i s t r i b u t i o n through the r e t a i l trade to the consuming rpublic. (2) Comparison of D i r e c t Methods of Performance Testing One e a r l y attempt was made to develop an a i d to the ev a l u a t i o n of beef b u l l s by using the accumulated show-ring honors. (Holbert, 1930) This was improved upon by the suggest i o n that the progeny of a beef s i r e be entered i n carcass c l a s s e s and so provide an index of the worth of the s i r e . (Stephenson, 1932) The f i r s t true Record of Performance (R.O.P.) t e s t was devised by Sheets (1932), who req u i r e d that the t o t a l body gains as w e l l as feed consumption ( i n c l u d i n g milk) from b i r t h to 365 days be taken. This method has been used i n experimental work conducted at the United States Department of A g r i c u l t u r e (U.S.D.A.), Experimental S t a t i o n at B e l t s v i l l e , Maryland. 9 Winters and McMahon>-<(1932), f e l t that a simple method must be devised df breeders are to be able to performance t e s t t h e i r animals. They suggested using body weight gain to 365 days of age as a measure of merit and pointed out that t h i s would place a premium on the calves from heavy m i l k i n g dams.^ A point considered desirable, by these workers. Black and Knapp (1936), proposed using an R.O.P. score based on the r e l a t i o n s h i p .05 '(E) (Q), where (E) i s the gain per 100# t o t a l d i g e s t i b l e n u t r i e n t s (T.D.N.), and (Q) i s the carcass grade i n per cent. They c a r r i e d out an a n a l y s i s of variance on the same c a t t l e evaluated by the methods of Sheets, Winters and McMahon, and Black and Knapp, to f i n d the l a t t e r gave s i g n i f i c a n t d i f f e r e n c e s between s i r e s which the other methods f a i l e d to do on the p a r t i c u l a r da^ta t r e a t e d . (Black and Knapp, 1938) ' • I t has occured to many i n v e s t i g a t o r s that the cor-, r e l a t i o n of r a t e and e f f i c i e n c y of gain with some r e a d i l y measurable c h a r a c t e r i s t i c might be high enough to use the l a t t e r as a measure of the former. A method of e l i m i n a t i n g the long, l a b o r i o u s -procedures already suggested would be d e s i r a b l e . Dawson" (1947), found b i r t h weight to be only 11 per cent h e r e d i t a b l e a f t e r c o r r e c t i o n s f o r the dams age and weight 10 were made. (Table 1 ) . The heaviest calves at b i r t h tended to be the ones that weaned out heaviest and reached slaughter weight e a r l i e s t but s i g n i f i c a n c e was lacking... I t would appear that b i r t h weight could be of some i n t e r e s t to the animal breeder but not as an i n d i c a t o r of rate; and e f f i c i e n c y of ga i n unless supported by a d d i t i o n a l growth data. Knapp and Woodward ( 1 9 5 D i n d i c a t e d the h e r i t a b i l i t y of l i v e weight at weaning to be 28 per cent, which i s about the same amount a v a i l a b l e to the d a i r y c a t t l e breeder s e l e c t i n g f o r increased milk and b u t t e r f a t production. This makes the O' E (variance due to environment.) a l a r g e f a c t o r , the major p o r t i o n of which i s due to preweaning n u t r i t i o n . Knapp and Black (1940) demonstrated s t a t i s t i c a l l y t h at 41 per cent of the v a r i a t i o n i n r a t e of gain observed between i n d i v i d u a l s during the s u c k l i n g p e r i o d was due to the n u t r i t i o n of the animal and s e l e c t i o n based on weaning weight merely s e l e c t s the progeny of heavy m i l k i n g dams who demonstrate the poorest beef conformation as measured v i s u a l l y . • ) . . One can r e a d i l y r e a l i z e why the h e r i t a b i l i t y of weaning weights would be low since seldom i s an animal allowed to r e a l i z e i t s f u l l genetic p o t e n t i a l to grow during a l l the preweaning pe r i o d because n u t r i t i o n i s l i m i t i n g . This i s evidenced i n the work of Lush (1930) i l l u s t r a t e d i n Figure 2 where i t may be observed that growth r a t e slows i n J u l y due to th C h a r a c t e r i s t i c T A B L E 1 H e r i t a b i l i t y Estimates  H e r i t a b i l i t y Basis of An a l y s i s .Species and/or Breed A u t h o r i t y O v e r a l l Weaning Score Thickness Score Lowness Score Smoothness Score O v e r a l l Weaning score Thickness Score Lpwness Score Smoothness Score Body Weight at 180 Days 50% 15% 4-6% 15% 30% 10% 13% 18% 33% 33% D a i l y Gain a f t e r Weaning Feed/lb Gain 50% W i t h i n year r e g r e s s i o n Aberdeen-Angus of o f f s p r i n g on Dam H a l f - S i b c o r r e l a t i o n P a t e r n a l HaIf-Sib c o r r e l a t i o n Poland China Danish Landrace PC x D l Koger and Knox (1952) Dickerson (194-7) C h a r a c t e r i s t i c H e r i t a b i l i t y Basis of A n a l y s i s Species and/or Breed A u t h o r i t y Y i e l d of Lean Cuts 33^ P a t e r n a l H a l f - S i b Poland China, Danish c o r r e l a t i o n Landrace PC x DL Dickerson (1947) Fatness Length of Carcass L i v e Weight at Y/eaning y e a r l i n g Rate of Gain 6 - 9 months 9 -12 " . 12 -15 " Body Weight at 6 months I! B i r t h Weight 75% • 2Q% 80 -/99# 10% 54% 15% 11% Progeny of Hereford B u l l s S i r e o f f s p r i n g c o r r e l a t i o n Dam-offspring w i t h  i n s i r e group Dam-offspring w i t h  i n s i r e group of Dam HaIf-Sib c o r r e l a t i o n Dam-offspring c o r r e l a t i o n ( c o r r e c t e d ) f o r age and weight of Dam Shorthorn Knapp and Wood ward ( 195D Dawson, Vernon, Baker and Warwick ( 1 9 5 D Dav/son (1947) i—• C h a r a c t e r i s t i c H e r i t a b i l i t y Basis of A n a l y s i s Species and/or Breed A u t h o r i t y Feed l o t Gain 70% S i r e - o f f s p r i n g c o r r e l a t i o n Hereford Knapp and Clark ( 1 9 5 l ) Weaning .Score Dairy Type 31% B u t t e r Fat Percentage Feed/100# Gain Length of Feed Period 72 Days-225 Bounds Weight at 72 Days Weight at B i r t h 14$ 30% 36% 26% 47% i n t r a s i r e daughter Jersey Dam r e g r e s s i o n ti 11 '" Ayr s h i r e " Jersey Regression of Durock Swine Progeny on mean of parents w i t h i n s t r a i n and year R e n n i e ( 195D Harvey (1949) Tyler and Hyatt(1948) Rennie (1951) Dickerson and Grimes (1947) •23% H 14 inadequacies of the mil k and feed supply which suppresses the growth p o t e n t i a l since normal absolute growth rate-continues to a c c e l e r a t e u n t i l puberty unless some set-back occurs. This s i t u a t i o n i s d e a l t w i t h i n d e t a i l using the Y o r k s h i r e p i g . Energy intake becomes l i m i t i n g by the tenth day f o l l o w i n g b i r t h . (Waldern and Wood, 1952) Dawson, Vernon, Baker and Warwick (1951), found that s e l e c t i o n f o r increased body weight at s i x months would be a slow method of improving r a t e of gain. Koger and Knox (1945) developed the equation f o r comparing a l l calves at a constant weaning age. A c t u a l l y i t W = w • db ' W = correcte d weight w = weight at weaning d = standard age de s i r e d b = the r e g r e s s i o n c o e f f i c i e n t .60 was developed from the a n a l y s i s of a l a r g e group of animals and introduces the in a c c u r a c i e s a s s o c i a t e d w i t h attempting to use the mean of a pop u l a t i o n to represent the i n d i v i d u a l . I t undoubtedly i s an improvement over attempting to compare animals at d i f f e r e n t ages and body weights. 15 I t may be safely concluded that weaning weight may be of value to the animal breeder when c u l l i n g females for milking a b i l i t y but is, not s a t i s f a c t o r y i n i t s e l f as a measure of the inherent a b i l i t y to grow. The, h e r i t a b i l i t y of rate and e f f i c i e n c y of gain of yearlings i s 85 percent as estimated by Knapp and Woodward (195D. This leaves l i t t l e doubt as to the time-when most advantageous selections might be made and therefore the post- weaning period has been adopted by p r a c t i c a l l y a l l investigat ors for the following reasons: (1) Increased accuracy of selection due to the ,high h e r i t a b i l i t y of animal differences for rate and e f f i c i e n c y of gain. (2) The 6-18 month period coincides with the usual supplementary feeding schedule. (3) I f the testing of steers i s practised, then i t is- merely a normal feed l o t proposition with the addition of group penning and • record keeping. (4) I f the i n d i v i d u a l b u l l i s tested the period of feeding i s coincident with the period - between weaning and f i r s t service. (5) The post weaning period i s one of major phys i o l o g i c a l change i n the l i f e processes of the animal. I f i t i s accepted that the yearling period i s the most desiraM.ee age for performance testing then the problem presents i t s e l f as to whether, steers, heifers or the i n d i v i d  ual bull, w i l l be treated. 16 The e a r l i e s t and a l s o the greatest amount of t e s t  ing work has involved the progeny t e s t w i t h e i g h t steers and a 168 day feeding p e r i o d r e q u i r e d f o r s i g n i f i c a n t r e s u l t s . (Knapp, P h i l l i p s , Black and C l a r k , 1942). The progeny t e s t using steers has one great advantage i n that there-are a v a i l  able eight carcasses f o r s c o r i n g and t e s t i n g which i s not so w i t h the i n d i v i d u a l performance t e s t . The advanced R e g i s t r y P o l i c y f o r Beef C a t t l e operating i n Ontario has reduced the number of steers i n the t e s t to f o u r . (Knox, 195D Some of the disadvantages of the progeny t e s t l i m i t i t s use and value: (1) The r e s u l t s are not known u n t i l a b u l l i s i n h i s t h i r d year ( p r o v i d i n g he i s mated i n h i s f i r s t y e a r ) . (2) The b u l l to be t e s t e d must be c a r e f u l l y hand mated as a y e a r l i n g to at l e a s t 16 cows to calve out 8 b u l l c a l v e s . To p r o t e c t the young b u l l the matings must be spaced w i t h a r e s u l t i n g spread' i n the ages of the calves to be t e s t e d . (3) The high cost of i n d i v i d u a l penning and feeding of groups of s t e e r s . Knapp, Baker, Quesenberry and C l a r k (1941) found the body weights of h e i f e r s at 18 and 30 months of age s i g n i f i c a n t l y d i f f e r e n t between s i r e groups ? when they were handled as a group under approximately uniform ranch c o n d i t i o n s . 17 This of course has the disadvantage of being slow i n showing r e s u l t s but o b v i o u s l y i s cheap, very p r a c t i c a l , and worthy of c o n s i d e r a t i o n . The use of performance t e s t i n g of i n d i v i d u a l b u l l s has a t t r a c t e d the i n t e r e s t of the "late-comers" to the f i e l d of the R.Q.P. t e s t i n g of beef c a t t l e . There i s much to be s a i d i n i t s favour: (1) Only one animal need be fed and housed. (2) R e s u l t s are known before the animal i s o l d enough f o r s e r v i c e . (3) More animals may be t e s t e d . (4) I n d i v i d u a l c h a r a c t e r i s t i c s may be studied which would otherwise be masked by group means. (5) More data may be obtained from a few i n d i v i d u a l s than from a s i m i l a r number of groups w i t h l e s s e f f o r t . There are two main disadvantages to the i n d i v i d u a l performance t e s t : (1) There i s no carcass a v a i l a b l e f o r s c o r i n g , ( p r o v i d i n g i t i s considered necessary to have the carcass s c o r e ) . (2) A l l r e s u l t s are l o s t or at l e a s t biased i f disease or accident should a f f e c t the animal under t e s t . 18 " (3) R e l a t i v e Importance of Conformation The formula f o r R.O.P. score developed by Black and -Knapp (1936), poses the question of the r e l a t i v e import ance of conformation and r a t e and e f f i c i e n c y of growth. Is i t d e s i r a b l e to consider beef type as 50 per cent of the t o t a l reasons f o r r e t a i n i n g or r e j e c t i n g a breeding animal as ' many i n v e s t i g a t o r s have done? I n t h i s connection Knapp (1939) c a r r i e d out extensive a n a l y s i s of the scores made on animals by t h e . t r a d i t i o n a l standards and l a t e r subjected to grading f o l l o w i n g slaughter. His general comment i n e f f e c t was that the s c o r i n g technique i s so inaccurate as to have no value except where d i f f e r e n c e s are l a r g e . I t seems i n e v i t a b l e that the breeder w i l l maintain a constant s e l e c t i o n pressure d i r e c t e d towards the continuance, of a reasonably desi.;rea*bl;e conformation and perhaps type should r e c e i v e l i t t l e or no d i r e c t c o n s i d e r a t i o n i n any s e l e c t i o n index devised. Koger and Knox (1952) estimated the h e r i t a b i l i t y score as 50 per cent (Table 1), which i n d i c a t e s that type may be c o n t r o l l e d q u i t e r e a d i l y . I n any case i t i s d o u b t f u l whether i t i s a d v i s r a b l e to a l t e r q u a n t i t a t i v e f i g u r e s on r a t e and e f f i c i e n c y of gain by a f a c t o r which i s merely d e s c r i p t i v e . 19 Knapp and C l a r k (195D concluded a f t e r c o r r e l a t i n g weaning scores and subsequent gains i n feed l o t t h a t , "...there i s l i t t l e value i n s e l e c t i n g feeder c a t t l e f o r r a p i d g a i n i f so l e dependence i s placed on v i s u a l methods of s e l e c t i o n . " An i n d i c a t i o n of how t h i s c o n s i d e r a t i o n c a r r i e s through to carcass grading may be found i n the data of Knapp, Baker, Quesenberry, and C l a r k (1941) i n which they found the only s i g n i f i c a n t d i f f e r e n c e between the progeny of s e v e r a l s i r e s when measuring carcass c h a r a c t e r i s t i c s such as percentage l e a n or percentage f a t i n r i b - c u t s , was y e a r l y v a r i a t i o n s which are the l o g i c a l consequence of changing feeds and management. Again i t i s necessary to conclude that there i s a l a c k of accuracy when s e l e c t i n g f o r the small d i f f e r e n c e s that e x i s t i n the conformation of beef animals, and the extreme cases w i l l be s e l e c t e d a g a i n s t by normal c u l l i n g procedures.. There seems to be no n e c e s s i t y of e i t h e r a score or carcass t e s t i n an index of merit designed f o r beef c a t t l e . Future work may r e v e a l the need f o r such carcass t e s t s but at present i t i s l i k e l y t hat over emphasis of t h i s aspect of the broader problem may becloud more urgent i s s u e s . 20 (4) Genetic Considerations Since the u l t i m a t e goal of a performance t e s t of beef c a t t l e i s as an a i d to s e l e c t i o n , i t i s desirable-: to consider the improvement that may be reasonably expected. The genetic v a r i a t i o n i n the body weights of the p o p u l a t i o n from which ase made the s e l e c t i o n of parents probably .amounts to as much as 30 per cent at 18 months of age. (Figure 1 ) . Since the h e r i t a b i l i t y of l i v e weight at t h i s age i s suggested to be 80 to 99 per cent (Knapp and Woodward, 1951) a breeder should r e a l i z e some rat h e r l a r g e and r a p i d increases i n the progeny of s e l e c t e d parents over the mean of the p o p u l a t i o n . Unfortunately such i s not the case as expressed by Knapp, Church and Flower (1951)• A f t e r continuous s e l e c t i o n f o r improved r a t e of gain f o r f i f t e e n years i n the S t a t i o n herd at M i l e s C i t y , Montana; "Improvement i n r a t e of gain and weight at 15 months of age were found to be 0.16 pounds i n d a i l y gain and 66 pounds i n body weight at 15 months of age." This i s somewhat l e s s improvement than hoped f o r considering the m a t e r i a l s a v a i l a b l e . One might suggest that even the gains made are i n part due to improved feeding and management. A p o s s i b l e c o n c l u s i o n i s that the c h a r a c t e r i s t i c s under consider a t i o n are i n h e r i t e d mainly i n some other than a purely a d d i t i v e manner. 21 In the c l a s s i c discussions presented by Lush (1945) i f : 0* 2T = t o t a l variance observed for the c h a r a c t e r i s t i c studied Cj2T = C^ 2H +(5 / 2 e +(5 " 2 E H tf2H = variance due to heredity (j 2 E = " " "environmental effects £^ 2EH = " " " i n t e r a c t i o n of environment and heredity. with further p a r t i t i o n i n g : 2G = that portion of the heredity of the c h a r a c t e r i s t i c controlled by the additive genes (the expected effect) ^ 2 D = v a r i a t i o n from the purely additive e f f e c t due to dominance - v a r i a t i o n from the purely additive e f f e c t due to the e p i s t a t i c e f f e c t , (non-additive i n t e r a c t i o n of n o n - a l l e l i c genes) H e r i t a b i l i t y i s t h e o r e t i c a l l y the r a t i o between the variance due to heredity and the t o t a l variance, i e : tf^H^T or ^ 2 G + ^ 2 D + ^ 2 I C^ 2T 22 If most of the c^2H were due to 2G there would be very marked effects due to the selection pressures exerted by the researchers at Miles C i t y since the simple Mendelian r a t i o s would hold. Lush (195D pointed this s i t u a t i o n out with three t possible explanations: (1) The actual h e r i t a b i l i t i e s are not as high as calculated. (2) The inaccuracy of measuring the improvement that takes place. (3) Actual s e l e c t i o n pressures are lower than believed. The f i r s t p o s s i b i l i t y does not apply i n this case since even a very marked error i n the present calculated h e r i t a b i l i t i e s would s t i l l provide ample variance due to heredity to allow reasonable effectiveness of se l e c t i o n . The second p o s s i b i l i t y i s also not applicable since the c h a r a c t e r i s t i c s considered are quantitatively measured with li m i t e d p o s s i b i l i t y of error. The t h i r d suggestion probably holds the answer for the slowness of improvement following selection for rate of gain i n beef c a t t l e and i t i s believed that a plausible explanation w i l l be developed i n the discussion to'this thesis. 23 To i l l u s t r a t e s the genetic problems which must be answered before p o s i t i v e s e l e c t i o n procedures.? can be develop ed are presented i n the following l i b e r a l quotations from Lush (1950) " . . . i f the additive genetic portion of the h e r i t  a b i l i t y (d 2G) i s hi gh, most of our e f f o r t s should be concent rated on sel e c t i o n - with i n d i v i d u a l s e l e c t i o n being the centre of the program, but supported by. l i f e time averages, sib testing, progeny testing, pedigree considerations." " I f h e r i t a b i l i t y values are as high as present reports indicate, we have only li m i t e d use for inbreeding and progeny testing, and the testing of i n d i v i d u a l b u l l s by feeding under controlled conditions would be very e f f e c t i v e . " Lush goes on to suggest that i f nicking i s demonstrated as being important i n ,the s e l e c t i o n for rate and e f f i c i e n c y of gain, then Individual s e l e c t i o n w i l l become r e l a t i v e l y less important and se l e c t i o n between l i n e s w i l l be necessary. " I f the cause (nicking) i s due to ep i s t a s i s ; then we w i l l t r y to f i n d l i n e s good i n the i r own performance but which w i l l cross well with other l i n e s . From the best of these crosses, new li n e s ? / i l l be b u i l t through a second cycle of inbreeding; enough to make the l i n e s d i s t i n c t , comparing them, crossing them, and breeding again for better crosses." I f nicking i s the r e s u l t of overdominance, make the inbred l i n e s f i r s t and then select those that do well i n crosses with other l i n e s . We judge the l i n e s very l i t t l e on their own 2 4 c h a r a c t e r i s t i c s , as long as they are good enough to he commercially usable. Once a good l i n e i s found, i t i s never crossed with the l i n e s with which i t ni c k s w e l l . " A l l these suggestions r e q u i r e much time and money to c a r r y out experimentally and therefore i n the meantime gains i n animal production can be made by performance t e s t  ing i n d i v i d u a l b u l l s paying a t t e n t i o n to blood l i n e s . ( 5 ) Rate and E f f i c i e n c y of Gain I t i s q u i t e obvious that both r a t e of gai n or growth and the gross e f f i c i e n c y w i t h which the process i s c a r r i e d out' are of v i t a l importance to the producer of l i v e  stock. Just which i s r e l a t i v e l y more important i s a matter of circumstance; i e ; where feed i s cheap and overhead i s high, r a t e of gain i s most important, however as.the r e l a t i v e cost of feed increases so does the importance of e f f i c i e n c y of gain. An i l l u s t r a t i o n may be made by observing the f i g u r e s from the G i l l i a m County C a t t l e Improvement A s s o c i a t i o n ( 1 9 5 1 - 5 2 ) - (Table 2 ) . The r a t e of gain ranged from 1.6 - 2.8 pounds per day and at a market p r i c e of 2 5 cents per pound returns on investment per day of 40 cents and 70 cents r e s p e c t i v e l y , an increase of 75 per cent. From the same p r o j e c t the e f f i c i e n c y f i g u r e s ranged from. 473 pounds of hay and 330 pounds of concent r a t e to 309 pounds of hay and 210 pounds of concentrate 25 HEREFORD BULL RESEARCH PROJECT 1951-52 Table 2 RESULTS..OF, THE. GILLIAM, COUNTY BEEF CATTLE IMPROVEMENT ASSOCIATION 1951-52 Bull No. Age i n Days 15/11/51 Weight i n lbs. 15/11/51 Weight i n lbs. ' 3/4/51 Gain , i n • 140 Days Average Daily Gain Efficiency per. 100 l b . Gain Grade Hay Cone. To p 10  36 250 ' 480 850 370. 2.6 314 217 327 B+ To p 10  31 260 475 870 395 ' 2.8 339 231 351 B+ To p 10  25 231 435 805 370 2.6 '317 220 325 B+ To p 10  23 272 455 820 ' 365 2.6 322 220 333 B+ To p 10  17 249 450 805.. • • '355 , 2.5 318 217 329 B+ To p 10  29 251 475 840 365 2V6 339 240 357 B+ To p 10  35 244 495 , 865 370 2*6 339 232 351 B To p 10  39 233 515 835 320 2.3 348 245 365 B+ To p 10  20 212 445 770 335 2.3 , 299 204 309 B To p 10  13 228 440 ' 725 385 2.0 • 309 210 319 B+ to tt om  1 0 10 229 410 675 ' 265 1.9 393 • 270 408 B to tt om  1 0 19 256 490 785 395 2,1 . '473 330 494 B. to tt om  1 0 33 251 505 '760 255 1.8 417 286 432 B to tt om  1 0 57 215 570 • 845 275 2.0 423 312 456 . B- to tt om  1 0 53 249 560.. .800 240 1.-7 479 315 486 B to tt om  1 0 9 205 390 635 245 1.8 350 260 378 B- to tt om  1 0 12 285 395 645 • 250 1.8 354 254 376 C+ 26 272 440 675 235 1.7 466 307 474 B 41 206 500 785 285 2.0 390 282 . 416 C 6' • ' 217 390 615 225 1.-6 382 274 ' 405 C+ 26 per 100 pounds gain. Using 40 d o l l a r s per ton f o r hay and 80 d o l l a r s per ton f o r concentrate the range i s 37 to 24 d o l l a r s per 100 pounds gain or a decrease of 35 per cent. These d i f f e r e n c e s w i l l take on more importance i f the c o r r e l a t i o n of r a t e and e f f i c i e n c y of gain i s low. As suggested "by Knapp and Baker (1944) i t has been assumed by many to be a b i o l o g i c a l n e c e s s i t y that r a t e and e f f i c i e n c y of gain be c l o s e l y c o r r e l a t e d , however as i n d i c a t e d by data of Winters and McMahon (1933); Knapp((1941); B l a c k w e l l (195D, i n a time constant p o p u l a t i o n the c o r r e l a t i o n of the two f a c t o r s ";'!SJ not high. This s i t u a t i o n becomes necessary i f i t i s to agree w i t h previous f i n d i n g s such.as the v a r i a t i o n i n . changing metabolic r a t e , (Brody, 1945, p468) w i t h i n c r e a s i n g body weight which means that the p h y s i o l o g i c a l l y younger animals w i l l be bearing a heavier b a s a l metabolism cost per u n i t body weight which w i l l be r e f l e c t e d i n a lowered feed e f f i c i e n c y . A quick maturing animal w i l l have passed i n t o the p e r i o d of f a t t e n i n g from the p e r i o d of greater muscle development. This c a l l s f o r a lowered gross e f f i c i e n c y since the energy content of f a t t y t i s s u e i s approximately s i x times that of p r o t e i n t i s s u e . An animal that grows moderately slowly and mainly i n the p r o t e i n sense w i t h correspondingly low feed i n t a k e w i l l show a high e f f i c i e n c y . These three h y p o t h e t i c a l animals may a l l be growing at the same absolute r a t e with widely d i f f e r e n t 27 e f f i c i e n c i e s . As a matter of f a c t the use of a time constant p o p u l a t i o n when de a l i n g with the growth phenomenon i s question able since i t immediately presents time as having a p h y s i o l o g i c a l meaning which i s an e r r o r since growth r a t e i s the balance between the growth stimulus and the r e t a r d i n g . e f f e c t s of the environment wi t h no reference to time except by the man imposed measuring devices. Stated another way, animal growth occurs r e l a t i v e to p h y s i o l o g i c a l time r a t h e r than s i d e r e a l time. I f time i s allowed to vary and r a t e and e f f i c i e n c y of growth are measured over a constant weight p e r i o d the cor r e l a t i o n between the c h a r a c t e r i s t i c s i n c r e a s e s . However as concluded by Hess (1948) while studying the i n h e r i t a n c e of food e f f i c i e n c y i n domestic f o w l , "There i s a d e f i n i t e inherent d i f f e r e n c e i n feed e f f i c i e n c y between i n d i v i d u a l s ' that cannot be explained on the basis of body weight, r a t e of gain, or time One of the most obvious reasons f o r the d i f f e r e n c e i s the e r r o r i n v o l v e d i n the measure of p h y s i o l o g i c a l age. Although body weight very n e a r l y measures p h y s i o l o g i c a l age i t has one c r i t i c i s m ; i t presupposes the same mature weight of animals under observation which i s not n e c e s s a r i l y true' even w i t h i n inbred f a m i l i e s . (Hammond, 1928) An animal r e c e i v e s the stimulus to grow depending upon the amount of grovidng l e f t to complete and i t w i l l f u l f i l l 28 this p o t e n t i a l to the a b i l i t y of the protoplasmic mass a v a i l  able for growth. Lerner (1938) considered this relationship i n the l i g h t of discussions, by e a r l i e r authors and presented the following formula for growth rate., (Q) at any time ( t ) . When rate of growth i s considered proportional to the time remain ing for the completion of growth. When rate of growth i s proportional to the weight yet to be gained. When the rate of growth i s inversely proportional to the elapsed time. When-the rate of growth i s inversely proportional to the weight already attained. Aw = f i n a l body weight At = time at Aw w = body weight k = log W2 - log W]_ I Q = k(At-t); II Q = k(Aw-w); III Q = k • t IV Q- = k ; w %2 ~ H 29 (6) Procedures The d e t a i l s of management, b u i l d i n g s , f a c i l i t i e s , and' record keeping w i l l not be r e l a t e d h e r e i n since they have been adequately d e a l t w i t h by Wi l l i a m s and Wood (1952) and i n the undergraduate essays of Doornenbal (1952) and P h i l l i p s (1952). (a) R a t i o n i n g of Test Animals The c o r r e c t method of feeding i n d i v i d u a l b u l l s i n order that the most accurate data w i l l be forthcoming i s a matter f o r conjecture and no one as yet has l a i d down a f i r m prccedure. which w i l l s a t i s f y a l l the requirements that may be suggested. Presumably an animal should be fed i n such a manner as to a l l o w f u l l expression of i t s "genetic p o t e n t i a l " to grow. ("Genetic p o t e n t i a l " i s used f o r want of a b e t t e r term to i n d i c a t e the t o t a l of a l l s t i m u l i which d i r e c t t i s s u e development). While ad l i b i t u m feeding would appear to permit f u l l expression of these growth p r o p e n s i t i e s i t s u f f e r s from 3 0 c e r t a i n disadvantages p a r t i c u l a r i i y at the experimental l e v e l as i n d i c a t e d by the f o l l o w i n g : (1) Feeding ad l i b i t u m tends to increase the p o s s i b i l i t y of d i g e s t i v e disorders and l o s s of a p p e t i t e which would of course be d e t r i  mental to the r a t e and e f f i c i e n c y of g a i n w i t h a bi a s of r e s u l t s . D i g e s t i v e upsets i n the ruminant type animal are much more d i f f i c u l t to c o r r e c t than In the non- ruminant. (2) The c h a r a c t e r i s t i c being measured i s that of r a t e of growth and to o b t a i n v a l i d data, a l l other f a c t o r s must be held constant. Allowing as l a r g e a f a c t o r as the n u t r i e n t i n t a k e of the animal to vary does not f i t i n t o the above w e l l founded requirement f o r sound experimental design. Although a p p e t i t e and r a t e of growth must have a degree of pos i t i v e c o r r e l a t i o n , the v a r i a t i o n i n d i g e s t  i b i l i t y and the decrease i n deposit energy ' per u n i t body weight due to a decreased p r o t e i n to f a t r a t i o w i t h increased feed consumption may give i n t e r animal v a r i a t i o n s which are f a l s e when inta k e of n u t r i e n t s are not standard. I t i s f a i r l y obvious that there would be d e f i n i t e advantages feeding at a set l e v e l something l e s s than ad l i b i t u m . The i n t e r p r e t a t i o n of ad l i b i t u m feeding i n t h i s * t h e s i s i s considered to be the f r e e choice i n t a k e of an animal which has access to a r a t i o n so c o n s t i t u t e d as to s a t i s f y a l l n u t r i e n t requirements without the c a p a c i t y of the 31 d i g e s t i v e ' t r a c t or the p a l a t a b i l i t y of the r a t i o n becoming a l i m i t i n g f a c t o r . -. Hammond's' (194-4) considerations. of the e f f e c t s of ! -i l i m i t i n g the inta k e of the animal are p e r t i n e n t to t h i s d i s c u s s i o n . His pre'sentation Implies that various body t i s s u e s F i g u r e 111 PARTITlONING OF BLOOD NUTRIENTS PAT have p r i o r i t i e s on the n u t r i e n t s i n the blood stream as i n d i c a t e d by the number of arrows. As Hammond v i s u a l i z e d the scheme, when the n u t r i e n t l e v e l drops the amount supp l i e d to each t i s s u e decreases. "When the supply of n u t r i e n t s i n the blood stream i s l i m i t e d we may suppose that one arrow i s deducted from each t i s s u e system and whereas the growth 32 of f a t i s completely stopped 1, b r a i n and bone growth continues." I t must be remembered however that Hammond's hypothesis was based on the work of McMeekan (1940, 1941) and Pomeroy (1942) i n which the animals r a t i o n was lowered from an adequately s u p p l i e d , w e l l balanced r a t i o n to one w i t h the same p r o p o r t i o n of n u t r i e n t s but lower i n amount so that p r o t e i n as w e l l as energy was l i m i t i n g . I f however only the t o t a l energy content of the r a t i o n i s decreased w i t h the l e v e l s of p r o t e i n r e t a i n e d at the ad l i b i t u m l e v e l there i s a completely d i f f e r e n t s i t u a t i o n developed from the one Hammond was studying. STORAGE c A l t e r i n g Hammond's diagram (Figure 4) wi t h the f a t p o r t i o n d i v i d e d i n t o the " t i s s u e f a t s " and "storage f a t " (Dukes, 1947), i t i s suggested that the f i r s t r e d u c t i o n i n the energy content of the r a t i o n w i l l only r e s u l t i n an arrow being 33 deducted from the "storage f a t s . " Further reductions would r e s u l t i n removal of some "tissue f a t s " and also c e r t a i n amounts of dietary protein which would he deaminized pre paratory to use as an energy source with the subsequent reduction i n the amino acids available for growth. When the energy l e v e l i s lowered s t i l l further an actual removal of tissue protein does r e s u l t . - . This thesis assumes.that storage f a t i s a reserve supply of materials which accrues when the energy intake i s i n excess of that which the body may u t i l i z e at that time. I t i s not under genetic control other than the s i t e of deposition. The bone f r a c t i o n of the body gain however must be under complete genetic control since i t i s the supporting structure of the body and ultimately l i m i t s the mature size of the animal. This i s i n keeping with the high p r i o r i t y bone tissue has for nutrients i n the blood stream. (Pomeroy, 1942). • • Muscle tissue since i t supports and provides locomotion for the genetically predetermined mass of the animal should also be under close genetic control. There i s further i n d i c a t i o n by the fact that the percentage protein of the body mass on a f a t free basis i s a constant over a l l but 34 the very e a r l y stages of growth and such a wide range of species as to incl u d e the r a t and the cow. (Haecker,1922); (Moulton, 1922); (Spray and Widdowson, 1950); (Murray, 1922); (Callow, 1944, 1947, 1948). McMeekan's ( 195D observations i n d i c a t e the con stancy and close c o r r e l a t i o n between bone and muscle t i s s u e which.further suggests c l o s e genetic c o n t r o l , " I n the many . hundreds of animals of a l l species and breeds that we have d i s s e c t e d down to t h e i r b a s i c t i s s u e s we have always found a heavy weight muscle a s s o c i a t e d w i t h a heavy weight bone; bi g muscles and l i g h t bone do not go to-gether." I t may be concluded t h a t bone, muscle and c e r t a i n t i s s u e f a t s represent the a c t i v e protoplasmic mass of the body which i s l a i d down i n the o r d e r l y manner d i c t a t e d by the gene m a t e r i a l of the i n d i v i d u a l animal. The deposit f a t i s merely a r e p r e s e n t a t i o n of the. energy in t a k e i n excess,.;/, of body requirements and.so i t seems j u s t i f i a b l e to suggest a feeding l e v e l s l i g h t l y below ad l i b i t u m f o r measuring the inherent d i f f e r e n c e s i n r a t e of growth. A few cons i d e r a t i o n s of the energy requirements of growing beef c a t t l e may a s s i s t i n reaching a d e c i s i o n on the proper feeding procedures *. Morrison (21st ed.) gives the f o l l o w i n g f i g u r e s f o r , "growing beef c a t t l e , fed l i b e r a l l y 35 f o r r a p i d growth." At a body weight of 500 pounds or a p p r o x i - ma telyvweaMng, the d a i l y net energy requirement i s 6.7 "to 7 .5 therms with a dry matter, i n t a k e of 11.7 to 13 .0 pounds. Work ing w i t h two unknowns i n simultaneous equations, assuming net energy values of .4 and .7 therms per pound of roughage and concentrate r e s p e c t i v e l y the r a t i o s 4 .97 pounds to 5.33 pounds of roughage to 6.73 pounds to 7.67 pounds of concentrate or, about one of roughage to one and one h a l f of concentrate. This i s a departure from the usual supplemental, system of feeding. A c t u a l l y i t i s a case of p r o v i d i n g enough roughage f o r proper d i g e s t i o n r a t h e r than making an a d d i t i o n of concentrate to r a i s e the T.D.N, of a mainly roughage r a t i o n . By v i r t u e of s i m i l a r c a l c u l a t i o n s the r a t i o of roughage to concentrate at a body weight of 1000 pounds i s two to one. The l e v e l of concentrate i s ' h i g h i n t h i s r a t i o n i n g f o r the reason that a beef animal cannot express i t ' s f u l l "genetic p o t e n t i a l " to grow during the most a c t i v e growth phase on a d i e t excess i v e l y high i n f i b r e . The G i l l i a m f C o u n t y Beef C a t t l e Improvement A s s o c i a t i o n (1950-52) have a^method of feeding t e s t animals i n which the roughage i s fed at a d e f i n i t e f r a c t i o n of the roughage i n t a k e . This e l i m i n a t e s the v a r i a t i o n i n the roughage to concentrate r a t i o v/hich e x i s t s when animals a c t u a l l y s e l e c t t h e i r r a t i o n c a f e t e r i a s t y l e . Unfortunately the roughage to concentrate r a t i o s they used are not those which provide f o r maximum growth f o r .weaner and short y e a r l i n g c a l v e s . (Table '%) This i s due to the high percentage growth r a t e and high metabolic r a t e which i s the r e s u l t of both r a p i d growth and the l a r g e r surface area per u n i t mass. Table 3 GILLIAM COUNTY FEEDING SCHEDULE "Calves weighing l e s s than 600# - 1# g r a i n to 3# hay " " 600# to• 700# ' - 1# " " 2# " " • over 700# - 1# " " l'# " Washington State C o l l e g e , (1951-52), chop, the roughage and concentrate to-gether i n a d e f i n i t e r a t i o . This has the advantages of The G i l l i a m County System and in. a d d i t i o n save'seoh-!therlabouro6ost;.ofv,feeding. I t i s noted that the roughage to concentrate r a t i o i n the Washington State College feeding t r i a l s supply the energy requirements of the animal. With the foregoing c o n s i d e r a t i o n s i n mind the method of feeding f o r the U.B.C. B u l l Testing P r o j e c t was developed. To avoid d i g e s t i v e d i s o r d e r s and to im prove the value of the f e e d . e f f i c i e n c y f i g u r e s , the p l a n of l i m i t e d feeding was adopted. The feeding l e v e l chosen was that of the minimum 37 recommendation for feeding r a p i d l y growing beef c a t t l e . (Morrison, 21st ed.) This data was plotted on an a r i t h  metic gri d and the feeding schedule was drawn off the smooth curve at«50 pound inter v a l s of body weight. (Table &). A l l feed weights were rounded to the nearest half pound fore cconvehience'm weighing. (Table 5)'. The formula t i o n of the actual r a t i o n as shown i n Table5a was done with reference to the recommendations of the National Research Council of the United States. (Recommended Nutrient Allow ances for Beef C a t t l e ) . The roughage was chopped to ensure uniform consumption. (b) Weighing Procedures I t i s observed by investigators working with the ruminant type animal that large errors may be introduced into their data by the body weight fluctuations due, to the variations i n the amount of rumen contents. There are several methods for reducing this error: ( 1 ) Averaging weights taken on three consecutive days. (2) Weighing at a set time r e l a t i v e to feeding and watering. (3) The removal of feed and water for a period of 10 to 12 hours before weighing to obtain a uniform shrink. T h e o r e t i c a l B u l l R a tion T A B L E 4 - Based on Morrison's "Growing Beef C a t t l e , Fed For Rapid Growth" Body Dry Net Hay Net Energy Concentrate Crude P r o t e i n (b) P r o t e i n i n Weight Matter E^nejg^ ^ Pounds Therms Supplied (a )Pounds Therms Required Hay Cone R a t i o n 300 7.2 4 .6 1 .47 .58 4 .58 5.73 4.0 .96 .17 1 .02 1.19 400 9.1 5.6 2.57 1.01 5.58 6.53 4 .57 1 .08 .3 1.14 1.44 500 10.7 6.3 3.97x 1 .59 6.29 6.73x 4 .7 1 .17 .46 1.18 1 .64 . 600 12.4 7.2 4 .93 1 .97 7.17 7.47 5.2 1 .2 .57 1.31 1.88 700 14.2 7.7 7.47 2 .98 7.68 6.73 4 . 7 1.24 .87 1 .19 2 .06 800 15.9 8.2 9 .77 3.92 8.22 6.13 4 .3 1 .28 1.13 1 .07 2 .20 900 17.3 8 .7 11 .37 4 .54 8 .69 5.93 4 .15 1 .32 1 .32 1.04 2 .36 1000 18.6 9.2 12.73 5.10 9.22 5.87 4 .12 1 .36 1 .47 1.61 2 .48 x Figures do not f i t smooth curve. (a) Assuming .4 therms per pound of Hay •7 therms per pound of Concentrate (b) Assuming Concentrate -17.5$ C.P.- Hay -11.6$ CP.' u> 00 HEREFORD BULL RESEARCH PROJECT 1951-52 Table No. 151 FEEDING SCHEDULE ANIMAL WEIGHT MORNING . HAY CONC. HAY CONC. 350 1.0 . 3.0 1,0. 3.0 400 1.'5 3.0 1.0 3.5' :- 450 1.5 3.5 1.5 3.5 ' 500 2.0 3:5 1,5* 3.5 550 2.0 3.5 2.0 4^0 600 2.5 3>5 2.5 4.0 650 . 3.0 3.5 3.0 3.5 700 4.0 3.5 ' 3.5 3.5 .750 .4-5 3.0 4.0 3.5 \ .800 5.0 3.0 5.0 3.0 850 5.. 5 3.0 5.-0 3.0 900 6.0 3.0 5.5 3.0 950 6-.0 '3.0 6.0 3.0 1000 6.5 3.0 6,0 3;0 HEREFORD BULL RESEARCH PROJECT 1951-52 Table 5a U. B. G. RATION No. 50 - BEEF BULL CALVES Ingredient Pounds per Ton ......... 100 inn ,. 2000 This ration was blended then pelleted into one-half inch cylindrical pellets. Table "5b PROXIMATE COMPOSITION OF ROUGHAGE AND CONCENTRATE Constituent Hay Concentrate Moisture ±6,61% 8.99$ Fiber 28.6 8.50 Protein (Nx6.25) 12.30 • 15,99 Fat 0.85 0.50 Ash 8,89 5.04 , Nitrogen Free Extract 32,75 60.98 Calcium 1.57 0.85 Phosphorous 0.22 . 0,75 The procedure':, fo l l o w e d i n t h i s p r o j e c t was to weigh at a set hour every seven days r a t h e r than every 14 or 28;days as i s common i s experiments w i t h beef c a t t l e . I t seems l o g i c a l to increase the degrees of freedom f o r greater s i g n i f i c a n c e . 41 Results and Discussion The re s u l t s of weekly weighings as recorded are pres ented i n Table 6 . As indicated i n the l i t e r a t u r e review there are cert a i n d i f f i c u l t i e s associated with evaluating growth. The f i r s t problem i n interpreting the data i s to find a basis for comparing or i d e n t i f y i n g animals; whether i t be made at a constant age or a constant body weighti In Table 7 the data i s given on an equal age basis and an extreme of 175# v a r i a t i o n i n body weight may be observed between b u l l numbers 7 and 10 at 35 weeks of age. According to. the h e r i t a b i l i t y data on Table 1 only 2Q% of the l i v e weight differences at weaning are attributable to genetic control; These differences w i l l have two effects on subsequent growth and development. (1) .The l i g h t weight calf has less "protoplasmic mass": with which to grow and therefore i s being discriminated against when compared with animals of the same age but a greater body mass. However, as indicated e a r l i e r t h i s difference i s l a r g e l y due to dam influences, pre sumably milk supply and i s considered by many a v a l i d point f o r discrimination. (Winters & McHahon 1933) (2) It has been observed that an animals tends to grow at an accelerated rate for a period following suboptimum n u t r i t i o n , which would coincide with the history of the l i g h t weaning calf; and therefore selection for rate of gain at a constant age would encourage low weaning weights and more prec i s e l y poor milking cows. (HcMeekon 1940), (Asmundsen and Lerner 1934) HEREFORD BULL RESEARCH PROJECT 1951^52 Table ;6T RECORD. OF WEEKLY WEIGHINGS FOR ALL ANIMALS ARRIVAL 1951 1952 Bull No. Nov 15 Nov 20 tfov 30 Dec 7 Dec 23 tfov 25 Dec •2 Dec 9 Dec 16 Dec 23 Dec 30 Jan 6 Jan 13 Jan 20 Jan 27 Feb 3 Feb 10 Feb 17 Feb 24 Mar 2 Mar 9 Mar 16 Mar 23 Mar 30 Apr 6 Apr 13 Apr 20 Apr 27 May 4 1 523 550 555* 565 569 582 588 608 620 630 655 660 675 675 692 702 728 745 762 767 782 800 810 830 335 2 545 560 582* 600 612 645 636 662 685 700 714 707 735 735 745 755 775 795 815 832 835 867 874 890 395 3 400 405 405" 410 430 448 440 471 475 491 504 510 540 545 560 572 590 628 625 635 662 680 685 705 730 4 445 460 463* 495 500 520 514 552 565 560 598 605 595 600 640 650 665 695 720 740 760 778 793 814 330 5 494 525 537* 555 570 593. 610 642 645 663 663 673 690 695 698 708 728 745 750 770 782 795 798 825 338 6 370 415 437* 428 452 466 475 495 505 515 535 531 543 569 575 585 600 620 636 650 670 693 694 702 724 7 400 425 437* 450 472 488 490 512 525 540 538 558 558 584 585 593 615 640 640 665 675 694 700 730 743 8 430 440 452* 470 480 500 503 534 547 565 570 582 593 600 631 651 662 680 685 697 720 747 755 765 790 9 540 555* 555 562 565 588 614 630 630 650 658 672 660 700 720 730 746 740 780 787 803 318 832 845 10 555 540* 542 572 585 612 610 630 637 539 648 670 590 712 725 741 762 782 800 805 316 835 843 11 328 328 325 344* 350 370 380 390 407 430 438 455 470 490 492 500 522 530 537 542 570 12 263 263 269 286 293 3073 320 526 342 355' 370 390 402 418 435 441 460 473 475 505 515 x - f i r s t weight on test. T A B L E 7 Weights at E q i v a l e n t Ages B u l l No. 43 Age Weeks 1 2 3 . 4 5 6 7 8 27 405 28 410 437 29 430 463 428 30 448 495 452 31 440 500 466 32 471 520 475 33 475 514 537 495 34 491 552 555 505 35 555 504 565 570 515 437 452 36 565 510 560 593 535 450 470 37 569 540 598 610 531 472 480 38 582 545 605 642 543 488 500 39 588 560 595 645 569 490 503 40 608 572 600 663 575 512 534 41 620 590 640 663 585 . 525 547 42 630 628 650 673 600 " 540 567 43 655 625 665 690 '' 620 .538 570 44 660 582 635, 695 695 636, 558 582 45 675 600 662 720 698 650 558 593 46 675 612 680 740 •. - 708 670 584 600 47 692 645 685 760 728 693 585 631 48 702 636 705 778 745 694 593 651 49 705 662 730 793 750 702 615 662 50 • 745 685 814 770 724 640 680 51 762 700 830 782 640 685 52 767 714 795 665 697 53 782 707 798 675 720 54 800 735 825 694 747 55 810 735 838 700 755 56 830 745 730 765 57 835 755 743 790 58 775 59 795 60 815 61 832 62 835 63 867 64 874 65 890 66 895 9 10 540 542 555 572 555 585 562 612 565 610 588 630 614 637 630 639 630 648 650 670 658 690 672 712 660 725 700 741 720 762 730 782 746 800 740 805 780 816 787 835 803 843 818 832 845 3 . 0 0 - 2 0 - 2 - 3 2 - 1 - 1 Age i n weeks m u l t i p l i e d by seven plus the i n d i c e l i s t e d under each b u l l s weight column w i l l be the b u l l s exact age i n days. 44 The two foregoing statements suggest opposite effects but there is no reason to suppose they are equal and c e r t a i n l y they are not measurable so they must be considered as two separate c r i t i c i s m s of age as the basis f o r comparing i n d i v i d u a l s ; If a l l the animals had been allowed f u l l expression f o r their genetic growth po t e n t i a l from b i r t h to weaning, i e : eliminate the environment due to dam differences, there would be some merit i n using age as the basis of comparison since then undoubtedly h e r i t a b i l i t y would increase and a measure of the economically important f a c t o r of ,lage to market" would be developed* This i s the basis for the R.O.P. program recommended by Sheets (1932) and previously described i n the review of l i t e r a t u r e * It would seem desirable that some basis other than age be used for comparing animals since i t introduces bias due to previous environmental e f f e c t s . Since the d i f f i c u l t i e s of expressing the c h a r a c t e r i s t i c rate of gain seem so involved i t may be well to digress and con sider some basic p r i n c i p l e s in an e f f o r t to progress l o g i c a l l y from simple, well established f a c t s to a consideration of the problem under discussion. The process of growth of animal tissue i s a series of biochemical reactions obeying the mass law. It would be l o g i c a l to expect the net result of a l l the reactions to also follow the basic rules of chemistry. Applying chemical .kinetics., to the growth process has merit since both are a study i n reaction rates. Growth may be cla s s e d as a " f i r s t order r e a c t i o n " s i n c e i t f i l l s the requirement,","the r a t e i s d i r e c t l y p r o p o r t i o n a l to the conc e n t r a t i o n of the r e a c t i n g substance", (Daniels 1948), or expressed i n the terms of the p h y s i o l o g i s t , "growth r a t e i s d i r e c t l y p r o p o r t i o n a l to the a c t i v e protoplasmic mass of the body." (Moulton 1922) , Since the r a t e i s d i r e c t l y p r o p o r t i o n a l to the con c e n t r a t i o n then i t must be measured r e l a t i v e to the concent r a t i o n at that p a r t i c u l a r i n s t a n t since i n the next i n s t a n t the conc e n t r a t i o n w i l l b e . a l t e r e d by an increment. Then r a t e =» W2 - W]_ - where W]_is the f i r s t and W2 i s the f i n a l weight of the ^2 ~ ^1 peri o d from time t]_ to t 2 . To make two a c t u a l measurements and W2 over the i n s t a n t t 2 - t]_is impossible and therefore recourse i s made to the f o l l o w i n g mathematical c a l c u l a t i o n : - dW m kW, or k - dW Where dW represents the r e l a t - dt dt dt W ion s h i p of an i n f i n i t e l y s m a ll body weight (W) to an i n f i n i t e l y s m a l l time pe r i o d ( t ) ; and k i s the instantaneous r e l a t i v e growth, i e ; r e l a t i v e to body weight (W) The summation of a l l the i n f i n i t e l y s m a l l changes i n body weight r e l a t i v e to changes i n time between the l i m i t s W and A, ( i n t e g r a t i o n ) r e s u l t s i n the f o l l o w i n g : 46 A dw = k dt Where w i s the i n i t i a l weight and w A i s the f i n a l weight. In w • i n A kt w = Aa Or In w - InA k s t When computing instantaneous r e l a t i v e growth rate the equation may be more conveniently written lnw 2 - lnw, k = i _ » (log w - log w ) x 2.303 t 2 - t £ i _ t 2 - t x Note that due to the selection of naplerian logarithms which are calculated to the base mem, the value f o r "k" when multi plied by 100 reads as per cent. A f i r s t order reaction may be i d e n t i f i e d by the c h a r a c t e r i s t i c straight l i n e plot which r e s u l t s when the con centration i s regressed on time on an a r i t h - l o g g r i d . There fore any reaction which w i l l give a straight l i n e 01a an a r i t h - lnw 2 - lnwj_ log plot w i l l have the reaction rate - ^ : — 7 :  t 2 - It i s pertinent to t h i s discussion to present c e r t a i n growth data to investigate the r e s u l t s of regressing log body weight on time. Figure 5 represents data collected on i n d i v i d u a l albino rats and plotted on a semi-log g r i d . The rats were fed a stock ration ad libitum. Attention i s drawn to the BODY WEIGHT IN GRAMS 48 remarkable f i t of the data to a s t r a i g h t l i n e over p o r t i o n s of the growth p a t t e r n . '. This - i s not the " s c a t t e r gram" type of p l o t u s u a l l y a s s o c i a t e d w i t h b i o l o g i c a l r e s u l t s but r a t h e r i s of the exactness expected when e x t r a c t i n g data from a com-., • p l e x chemical r e a c t i o n . The statement should now be made that an animal tends to grow at a constant percentage r a t e r e l a t i v e to body weight, over c e r t a i n p o r t i o n s of t h e i r growth curve. This l a t t e r statement i s b e t t e r i l l u s t r a t e d by r e f e r  ence to c e r t a i n data presented i n Figure 6 . This same data was accumulated by Waldern (1952) working with a l a r g e commercial swine herd to demonstrate the l e v e l s of production which may be a t t a i n e d by improvements i n feeding and management. The "k" values f o r instantaneous r e  l a t i v e growth r a t e are given on each segment of t h e growth diagram. From the "k" values the gain per day may be a c c u r a t e l y c a l c u l a t e d . For example number 323 at 40 days of age weighed 13.7 pounds and was gaining at 4 .9 per cent per day or .67 pounds per day. The same p i g at 50 days of age weighed 22 pounds, was s t i l l g aining at 4 .9 per cent but i n absolute terms was now gaining 1.1 pound per day. This method of p r e s e n t a t i o n i s a more accurate a p p r a i  s a l of the growth of the animal than are the usual methods o f c a l c u l a t i n g the mean gain per day. In t h i s case the mean r a t e of BODY WEIGHT IN POUNDS 50 gain per day over the 49 - 50 days of age period was .83 pounds per day. Actually t h i s i s not a true f i g u r e , since only f o r an instant during the period did the pig lay down body tissue at that rate. It i s interesting to compare the barrow number 323 with the g i l t number 320. Bote that the barrow has a greater r e l a t i v e growth rate during the second growth phase than the g i l t but'makes less absolute body gain because i t breaks into a slower growth phase 10 days e a r l i e r . It i s obvious that the longer an animal maintains i t s e l f on a rapid growth phase the shorter w i l l be the time to market. Note that the foregoing observations would have been ;: impossible had the data, been that of groups of i n  dividuals or the measurements had been taken less frequently. As a further i l l u s t r a t i o n of the broadness: of the application of instantaneous growth rate, observe figure 7 the a r i t h - l o g plot of data collected from two "Black-tailed Deer". Again the data f i t s a straight l i n e over certain growth phases and as noted i n the same data "Blackie", although growing at a lesser instantaneous r e l a t i v e rate managed to maintain, each phase longer than '''Brownie-" and so a t t a i n a greater body weight.' ' The foregoing applications of the a r i t h - l o g method of p l o t t i n g growth data, from which the conclusion has been drawn that animalstend to grow at a constant percentage rate r e l a t i v e 51 C O E H I o CQ « E H E H < £ D H 1 •cc ID a —i o o o o SdNfiOd Nl 1H0I3M iaoe 52 to body weight over certain portions of t h e i r growth curve, suggests that some worthwhile information may be obtained by treating the in d i v i d u a l b u l l data i n a sim i l a r manner. Figures 8 ..to 17 represent the bulls plotted on a r i t h - l o g graph paper and f i t t e d with a straight l i n e by the method of least squares. Again we find a remarkable f i t of data to the l i n e . There i s an advantage not previously mentioned in using the instantaneous r e l a t i v e growth rate method of presenting data, Host other methods have attempted to carry on calcula tions f o r rate of gain with figures f o r body weight d i r e c t l y as they were measured despite the variations which unavoidably occur due to " f i l l " of the g a s t r o - i n t e s t i n a l t r a c t . The rest usually attempt to draw i n a smooth curve with limited points. The instantaneous rate method provides a mean l i n e which is actually the true measure and.not merely an average, therefore calculations should be made with body weight figures taken off the s t r a i g h t . l i n e . ' Another factor of course i s that the human eye i s much more sensitive to variations from a straight l i n e than from a curved l i n e . If the.line of best f i t f o r the growth data on b u l l number dine i s extended to zero days f o r an estimate of b i r t h weight, the body weight arrived at i s 269 pounds, obviously impossible. The only conclusion 10 be dra,wn i s that the b u l l Figure 8 53 I m — i r 1 5 ta p o o 00 o 8 6 o o o CM 9QNQ0d 1CI TVJCNV 40' IH3I3M IQOS 9oo 800 7ob 600 II 5oo CO Q o 4 00 BULL NO-3 lrt\4*a<Xfi&fr+5.7SQ0 T Z7Q 360 400 w S5Z 780 9/0 1 8 300 2oo 162 180 198 216 234 . 252 270 288 306 324 342 360 378 396 414 432 450 468 AGE OF ANIMAL IN DAYS F i g u r e 11 56 00 v O -4- o U N -3- CM C O L v r-i Ok ~t of v O us O N 1 • <r\ . . . I o 1 s £ M O O * oo t o I • >0 <J> CA r o o — j < 1 O O o o { \ s r o u 1-5 r I \ ) r o L 1 1 CM C O < > > i s >o r o l r o \ CO s 0 52 > - • t o 4 •% CM S3 M % i \ < ) \ o <g t*- 53 v ta > <»• CM tt-, U N O J CM W n N S U - t f • c C O CM v \ n L J 1 „ v O H o CM t o ON r-i o t o r-i CM s O • < \ 5 t- 5 c c > O O ' in c h i r H SCMlCd Nl TVWINV dO IHDI3M 1(103 Figure 12 •00 vO -4- Q <M j in o> j i .n * w f cn 1 1 r E- \ < \ 2 i CO in ^ lO 4 2! > K 3» I. o • Q v 1 * vO _ a N O o o 5 k i < • j . Yf\ t<* **J \ ) (» t 1 j ;• • r 1 p B i3 - d -CM cn \ 11 , c >i 1 NO O o hi CM g > n \I - o f CN H ( i L > IT\ O CM H O \ • v < > V ™ cn CM L t f i n CM to ON ,_| 8 H CM vO o . c cn <? 8 8 VO 8 O O «»- 8 to samod Ni TVWINV so XHOISM xaoa Figure 13 58 00 NO -4 O v \ -* CM cn - 4 -* r H - 4 vO O cn to m o NO cn cn -4- cv cn N O o cn CO co to CM O MA  CM M AN  CM UT\ O CM w -4" cn CM N O H CM 00 O r H Y o ZD 0 0 0 >0 vO H *0 l> o , o o t- t» NQ O 5 l_LJ_ 3; •1 i o o cn o o o o o NO o o O O 8 tn 8 CM SdNJlOd NI 7VWIMV JO XH0I3M 1(103 f\5 O O BODY WEIGHT OF ANIMAL IN POUNDS 8 8 o o CM 8 -a o o 00 X & i to c r- 1 !5S - 9 J - 09 BODY WEIGHT OF ANIMAL IN POUNDS o o o o VJ1 8 8 -a 8 \ > — u 1 1 V. 0 \ n - u — *i J ) > k r > > r • J \ ! < i v \ ( ) 4 J > > g £ w N J o o ° ^ & £ £ o. °t o II o 8 it c 9T e j n S i d T9 62 Figure 17 to vO -4- O w\ -4- CM \i -* « X A •B NO O ( >n h c n • S < ol Ir. O to c n > £: < 4- * In v D 3 o NO c n C ->•: ii O 6- o > E- vO r \ \ \t } 5 i i c n s q -4- CM i If I m c n E s v v O r \ o ^ CO r I > to Q CM g > > r H >A O < s < CM H i T k CM Ct, \ \ V \ O CjJ \ m 9 » c n CM c 1 \ > G if > r r H CM 1 to ON r H . o CM j s VO 8 CM SdNnOd NI TVWINV" JO JH0I3M 1009 has had at l e a s t one other more r a p i d growth phase preceding; the one during which the data was c o l l e c t e d . This i s reasonable since the other species studied p r e v i o u s l y had a t l e a s t one r a p i d growth phase during very e a r l y l i f e . E x t r a p o l a t i n g beyond the l i n e of best f i t to the age of three years leads to a body weight of 5012' pounds, again an obviously i n c o r r e c t f i g u r e so there a l s o must be at l e a s t one more growth phase f o l l o w i n g the one under i n s p e c t i o n . A s i m i l a r s i t u a t i o n e x i s t s f o r a l l b u l l s i n t e s t except f o r one important Item. There i s no way of knowing whether or not a l l the b u l l s are on the same phase of growth. As a"matter of f a c t b u l l number 5 made the change from one phase to another during the t e s t period. Table 8 presents the "k" values or instantaneous r e l a t  i v e growth rates of the b u l l s arranged i n order of magnitude. Note there appears to be a d e f i n i t e grouping, I.e. b u l l s 3?4 , 8 , 6 ,7 are growing at very n e a r l y the same re'lative growth r a t e w h i l e 1 0 , 9 , 1 , 2 are proceeding as a group at a slower r a t e . B u l l number 5 grew the most r a p i d l y f o r a time and then "broke" and grew the most sl o w l y . There are three p l a u s i b l e explanations f o r the above: (1) B u l l s 1 0 , 9 5 1 , 2 , have had a major break i n t h e i r growth curve while 3)4,8 , 6 , 7 , have not done so and are growing at a more r a p i d r e l a t i v e growth rate-f (2) B u l l s 1 0 , 9 , 1 , 2 , have a very r a p i d " j u v e n i l e " per i o d of growth r e l a t i v e to b u l l s 3,4 , 8 , 6 , 7 , and so are more e a r l y maturing and have a compensatory slowing of growth during the period under i n s p e c t  i o n . T A B L E 8 B u l l : number: 5 3 4 8 6 7 10 9 1 2. - 5 ' "k" -..00464 .00384 .OO368 •00355 .00343 .00326 .00297 .00291 .00276 .00286 .00227 difference between subsequent "k" values .00080 .00016 00013 .00012 00017 - 00G29 .00016 00015 .0000 00049 THE RELATIVE GROWTH RATES ARRANGED IN ORDER OF MAGNITUDE \ 65 (3) B u l l s 3 ) 4 , 8 , 6 , 7 were on a sub-optimum plane of n u t r i t i o n during the p r e - t e s t period and are now showing the c h a r a c t e r i s t i c increase i n growth f o l l o w i n g an increase i n i n t a k e . I t would appear i n any case that the growth p a t t e r n of b u l l s can be q u i t e d i f f e r e n t and has i m p l i c a t i o n s concern ing the production of commercial beef: , (1) Animals such as numbers 10, 9, 1, and 5 appear to have a very r a p i d instantaneous r e l a t i v e growth r a t e previous to the t e s t p e r i o d since t h e i r f i r s t t e s t weights were consider ably above the average of a l l the animals. F o l l o w i n g a .major s h i f t i n r e l a t i v e growth r a t e they became slow growing but i t must be remembered that they now have a r e l a t i v e l y l a r g e body to maintain so that they might be best s u i t e d f o r marketing at a low body weight such as those required, f o r baby beef. (2) A very d i f f e r e n t p a t t e r n i s followed by animals 3 , 4, 6, 7) 8. They have only a moderately high weaning weight which r e q u i r e s a slow r e l a t i v e growth r a t e during e a r l y l i f e f ollowed by a l e s s severe s h i f t i n r a t e than noted f o r the previous group of b u l l s with a r e s u l t i n g r a p i d r e l a t i v e growth r a t e during the t e s t p e r i o d . This s i t u a t i o n t y p i f i e s the animal w h i c h r w i l i have a r e l a t i v e l y low accumulated, maintenance r e q u i r e  ment and therefore being the most s u i t a b l e type f o r c a r r y i n g 66 through to a heavy market weight. This animal would be slow to, re.ach baby beef weight but more r a p i d at a t t a i n i n g a 1000 pound market weight. (3) B u l l number 2 represents a .group which have not the a t t r i b u t e s of e i t h e r of the preceeding s i t u a t i o n s . This animal grew slowly i n the preweaning p e r i o d as i n d i c a t e d by the low body weight at the commencement of .the t e s t . F o l l o w i n g the c h a r a c t e r i s t i c , break i t s growth r a t e was again very slow so there was no compensation during e i t h e r growth phase. This b u l l appears to have l i t t l e growth p o t e n t i a l to recommend i t f o r breeding.' Although a body weight of 1000 pounds more c l o s e l y approaches the market weight of beef c a t t l e i t appears adv i s a b l e to make comparisons i n t h i s work at body weights a c t u a l l y measured rather than t r u s t an e x t r a p o l a t i o n since there i s no. guarantee that there i s not a major s h i f t i n growth r a t e immediately beyond the per i o d of data c o l l e c t i o n . I t i s probably q u i t e v a l i d to compare animals at one or two points during the t e s t p e r i o d without some f a c t o r to weight the data because of d i f f e r e n c e s i n weight f o r age since we already considered that weaning weight d i f f e r e n c e s are mainly a r e s u l t of environmental d i f f e r e n c e s . 67 Reference to Table 9 presents the animals at the constant body weights of 575 and 675 pounds. I t may be noted that since they are taken from the r e g r e s s i o n l i n e s that they are always i n the same order except f o r b u l l #5 which has two segments of regressions l i n e s . TABLE 9 RATE OF GAIN TAKEN AT THE SAME BODY WEIGHT B u l l No. 1 2 3 4 5 6 7 8 9 10 Rate of Gain at • 1.59 1.59 2.21 2.12 2.66 1.98 I . 8 7 2.04 I . 6 7 1.71 575# B.W. Rate of Gain at 1.86 1.86 .2 .60' ' 2.48 1.54 2.32 2.19 2.39 1.96 2.01 675# B.W. I t i s i n t e r e s t i n g to note the r e s u l t of comparing b u l l s i n weight groups rather than at an exact weight. Con s i d e r the r a t e of gain of b u l l s numbers 2 and 9 at a body weight of 600 and 650 pounds which would represent the extremes of comparing animals i n weight groups of 50 pounds. Table 10. TABLE 10 BULLS COMPARED. IN 50 POUND BODY WEIGHT GROUPS B u l l No. 2 9 _ 600# B.W. 1.66 .1.75 650# B.W. 1.79 1.89 68 Note that b u l l number 2 can be considered as being more d e s i r a b l e .than number 9 f o r the c h a r a c t e r i s t i c r a t e of gain i f the mean body weights at ?/hich they were compared were allowed to vary .within as narrow a l i m i t as 25" pounds ©ittier way. Conversely b u l l number 9 could show an excessive super i o r i t y over b u l l number 2 i f number 9 were at the greater body weight. This would be an unfortunate s i t u a t i o n which i s being repeated i n many programs i n operation at the present time. B u l l number 9 of course was demonstrated as having a much super i o r r a t e of growth by a d e t a i l e d observation of the growth p a t t e r n . Another i n t e r e s t i n g e r r o r might a r i s e i f an animal has a change In instantaneous r e l a t i v e growth r a t e during the t e s t p e r i o d . For example, In the case of B u l l : N o . 5 ? i f his \ • growth r a t e i s expressed by the usual average r a t e of gain method a s e r i e s of " r a t e s " i s obtained dependent upon the pos i t i o n of the "breaks" i n h i s growth curve r e l a t i v e to the i n i t  i a l and f i n a l weights s e l e c t e d f o r the determination of average ra t e ; of-.gain* ..Results-'a p.er- i l l u s t r a t e d i n Table 11. I t i s obvious that t h i s animal might be considered as an i d e a l animal i f h i s gai n i s measured from 500 tot.650 pounds since he i s gaining at the r a t e of 2 .67 pounds.per day. This r a t e i s probably close to the maximum achievable by an animal at t h i s body weight. On the other hand i f the r a t e of gain i s 68 (a) expressed over the weight range 650 to 800 the bull;.:is g a i n i n g 1.52 pounds per day. A f i g u r e which must be cl o s e to the minimum r a t e of an animal of t h i s weight under the management cond i t i o n s of the experiment. There f o r e b u l l no. 5 might be chosen as the best or poorest b u l l on t e s t depending upon the t e s t p e r i o d . TABLE 11 EFFECT OF VARIATIONS IN THE TEST PERIOD Body weight 500-650 550-700 650-800 Range Average Rate of Gain per day 2.67 l b s . 2 .05 l b s . 1.52 l b s . 69 Note that the d i f f e r e n c e s are a c t u a l l y greater than those observed on the performance t e s t . The suggest i o n may be made that extensions of the p e r i o d would l e s s e n t h i s e r r o r but un f o r t u n a t e l y t h i s procedure would p o s s i b l y introduce another "break" i n the r e l a t i v e growth r a t e which would increase the e r r o r i n v o l v e d i f i n t e r p r e t a t i o n i s made by conventional methods. I t appears from the observations made that some of the procedures at present being followed f o r the per formance t e s t i n g of beef b u l l s are i n t r o d u c i n g e r r o r s which could r e s u l t i n an i n s i g n i f i c a n t s e l e c t i o n pressure which may i n pa r t account f o r the l a c k of improvement ex perienced i n the f i f t e e n years of t e s t i n g at M i l e s C i t y , Montana. I n the experiment conducted on beef b u l l s at t h i s i n s t i t u t i o n the unique s i t u a t i o n i s provided that 10 b u l l s , maintained under uniform c o n d i t i o n s , fed e x a c t l y the same amount of feed per u n i t of body weight, gainr i n body weight at varying r a t e s . Included i n any d i s c u s s i o n on the methods of measuring these v a r i a t i o n s should be some observation on the reasons f o r the v a r i a t i o n s , p h y s i o l o g i c a l or otherwise. 70 The f i r s t step i n a l o g i c a l c o n s i d e r a t i o n of v a r i a t i o n s i n r a t e of gain i s the i n d i v i d u a l s a b i l i t y to d i g e s t the feed. This p o i n t was discarded as a p o s s i b i l i t y f o l l o w i n g work at Cambridge. (Dunlop, 1933)- Jordan and Staples ( 1 9 5 D gave the standard e r r o r of d i g e s t i b i l i t y as being l e s s than 1 per cent on a r a t i o n c o n t a i n i n g 45 per cent dry matter. Using round numbers the energy content of the t o t a l r a t i o n may be assumed to be . 6 therms per pound dry matter and thence on a dry matter i n t a k e of 10 pounds, the extremes due to d i f f e r e n c e s i n d i g e s t i b i l i t y would be 4 per cent (.24 therms) or 6.12 therms to 5.88 therms. This amount of energy would account f o r .26 pounds of ..body weight gain per day between the animals having the upper .and lower, extremes of d i g e s t i b i l i t y (Assume 909 C a l o r i e s per pound body gain, Brody, 1947). This of course i s r e l a t i v e l y s m a l l compared to the 1.0 to 2 pound per day d i f f e r e n c e i n r a t e of g a i n noted f o r animals on performance t e s t s . D i g e s t i b i l i t y v a r i a t i o n i s most probably only a r e s u l t of i n a c c u r a c i e s of measurement, v a r i a b i l i t y i n q u a l i t y of feed or i n s u f f i c i e n t time allowed f o r the rumen m i c r o f l o r a •to reach a s t a t e of dynamic e q u i l i b r i u m . I f d i g e s t i b i l i t y i s not considered the f a c t o r which 70. accounts f o r v a r i a t i o n s i n r a t e of gain then the answer must l i e i n one of the energy p a r t i t i o n s ; b a s a l metabolism, maint enance or growth. Basal metabolisn has been the subject of very i n  t e n s i v e study by. a great many i n v e s t i g a t o r s who found i t . to be by. a c t u a l measurement a r a t h e r f i r m f i g u r e based on surface area and summed i n the equation, B.M. « 70.5 x W*7 (Brody, 194-7), where "B.M." i s b a s a l metabolism i n C a l o r i e s per day and "W" i s the body weight i n kilograms. Deighton found that b a s a l metabolism does not account f o r v a r i a t i o n s i n r a t e of gain of p i g s . (Dunlop, 1933)' Further confidence i n the l a c k of v a r i a b i l i t y ex pected i n bas a l metabolism may be taken from the experimentally demonstrated f a c t that under ba s a l c o n d i t i o n s the e x c r e t i o n of n i t r o g e n approximates 2 m i l l i g r a m s per C a l o r i e of b a s a l heat produced i n the sp.e'cies ranging from the mouse to the mature swine. This would suggest that the a c t i v e protoplasmic mass of the body i s metabolizing at constant r a t e as would be ex pected of the sum of a s e r i e s of chemical r e a c t i o n s proceed ing with the same concent r a t i o n of reactants under s i m i l a r c o n d i t i o n s . Any c o n s i d e r a t i o n of maintenance r e l a t i v e to v a r i  a t i o n s i n growth i s very n e a r l y a repeat on the d i s c u s s i o n of basal metabolism. The maintenance of two-animal bodies 72 under the same environment (temperature), a c t i v i t y , energy int a k e and body weight would reasonably be the same since as stated i n the preceeding paragraphs, the b a s a l metabolic r a t e by a c t u a l measurement i s a f i r m r e l a t i o n s h i p with surface.area subject to the e r r o r s i n v o l v e d i n making such a complex measure ment. Maintenance could be m a t e r i a l l y d i f f e r e n t between animals p r o v i d i n g t h e i r body temperatures were markedly d i f f e r e n t , but such i s not the case as i n d i c a t e d by the temperature f o r Jersey Cows of 101 .1 - 0 .5° F and of the'beef cow of 101.0. (Dukes, 194-7). Another f a c t o r which may be i n v o l v e d i f the maintenance r e q u i r e  ment of two animals- i s d i f f e r e n t i s their.'body composition.. I f the one animal has a greater percentage f a t i t w i l l have a lower maintenance requirement because the t i s s u e i t s e l f has no a n a b o l i c requirements to keep i t i n r e p a i r since i t s metabolism i s merely d e p o s i t i o n and withdrawal. I n a d d i t i o n the i n s u l a t i n g e f f e c t of f a t would tend to lower the costs of maintaining homeothermy. • Although the maintenance requirements of animals may not d i f f e r a p p r e c i a b l y , the suggestion that body composition might d i f f e r leads to an a t t r a c t i v e e x planation of the d i f f e r  ences which have been observed f o r the r a t e of g a i n of beef animals. This c o n s i d e r a t i o n may best be i l l u s t r a t e d by r e f e r - ence to the energetics of a h y p o t h e t i c a l s i t u a t i o n , created by W i l l i a m s and Wood (1952) based on composition f i g u r e s of beef 73 c a t t l e published by Haecker (1922) . Case I -a 700 pound animal gaining i n such a way that 10 per cent of the weight gain i s i n the form, of f a t and 16.5 per cent i s i n the form of p r o t e i n ; each pound of body weight gain w i l l represent the storage of approximately 860 C a l s . Case I l - a 700 pound animal gaining i n such a way that 20 per cent of the weight gain i s i n the form of f a t and 14 per cent i s i n the form of p r o t e i n ; each pound of body weight gain w i l l represent the - storage of approximately 1200 C a l o r i e s . This means that f o r each 1000 C a l o r i e s of net energy consumed above maintenance, the animal i n Case I w i l l be able to g a i n 1.. 18 pounds per day, while the animal i n Case I I w i l l g a i n 0.83 pounds per. day. Such an example i s i n keeping w i t h the r e s u l t s o b t a i n  ed by i n v e s t i g a t o r s conducting performance t e s t s as-;..we 11 as ' those who have made complete t i s s u e separations of e n t i r e carcasses To apply the " v a r i a t i o n i n body composition" concept to the b u l l s on t e s t at t h i s i n s t i t u t i o n , the use of t h e o r e t i c a l c a l c u l a t i o n s are necessary since the b u l l s were not given any slaughter or carcass e v a l u a t i o n . Consider b u l l s #2 and #3 at a body weight of 600 pounds. Their c a l c u l a t e d energy p a r t i t i o n i n g appears i n Table 12. 74 The b a s a l metabolism i s estimated from the formula p r e v i o u s l y c i t e d : B.M. = 70.5 x W^ Maintenance requirement i s assumed to be lJO per cent of b a s a l metabolism.. This assumption may be subject to c r i t i c i s m but since i t i s a r e l a t i v e f i g u r e a p p l i e d to both animals i t may be used without introducing:;r.g- any a p p r e c i a b l e - e r r o r s . Net energy intake i s c a l c u l a t e d from the a c t u a l feed i n t a k e . Energy f o r growth i s the net energy intake minus the requirements f o r ba s a l metabolism and maintenance. The ac.tual r a t e of gain has been c a l c u l a t e d from the r e g r e s s i o n equation f o r each b u l l . The gain i n protein'and f a t t i s s u e i s c a l c u l a t e d using the a c t u a l r a t e of gain i n two simultaneous equations, assuming p r o t e i n and f a t t i s s u e s to have the C a l o r i c contents, of. 450 and 3900 C a l o r i e s r e s p e c t i v e l y . This c a l c u l a t i o n i n c l u d e s the i n  crease i n water but ignores ash since i t i s such a r e l a t i v e l y small q u a n t i t y . i e ; X «** Y must - r a t e of gain and 450X + 3900Y . - 2600 C a l o r i e s Table 12 ENERGY PARTITIONING FOR TISSUE GROWTH Net c a l c u l a t e d Maintenance Energy Energy Rateoof «•<','/., Basal Metab. 130$ of B.M. inta k e f o r Growth Gain '' ." c a l s . c a l s . c a l s . c a l s . l b s . 3580 4650 7250 2600 1.66' 3580 4650 7250 2600 2.30 Gain i n P r o t e i n Gain i n F a t t y Tissue Tissue B u l l #2 1.12 .54 B u l l #3 1.85 .45 75 Note th a t "bull # 2 i s making approximately 36 per cent of h i s gain i n the form of f a t t y t i s s u e while b u l l # 3 i s only making 2 0 per cent of h i s gain as f a t t y t i s s u e . I t i s of i n t e r e s t to consider t h i s c a l c u l a t i o n i n the l i g h t of the r e s u l t s of the v i s u a l e v a l u a t i o n made by seven competent t l i v e s t o c k men with reference to the" scorecard recommended by the Canadian- Hereford A s s o c i a t i o n . . ( T a b l e 1 3 ) . B u l l # 2 graded highest and b u l l # 3 lowest i n the e s t i m a t i o n of the c l a s s i f i e r s . By view ing the p l a t e s made during the t e s t , any experienced eye can perceive that b u l l # 2 i s "rounder" and "smoother" than b u l l #3. This i s p o s s i b l y because some f a t i s l a i d down subcutaneo.usly and would tend to produce a "smooth" appearance while muscle t i s s u e i s added unevenly i n a a n t e r i o r to p o s t e r i o r manner (McMeekan, 194-2) to already e x i s t i n g muscle bunches so exaggerat ing the already uneven o u t l i n e r e l a t i v e to the show-ring i d e a l . This suggestion that body gains d i f f e r i n composition between animals so e x p l a i n i n g the d i f f e r e n c e s i n r a t e of gain and p o s s i b l y e x p l a i n i n g some of the v i s u a l e v a l u a t i o n d i f f e r e n c e s makes an a t t r a c t i v e theory. I t would be desirable.', that i t were true since i t would, e x p l a i n the l a c k of c o r r e l a t i o n which has been found between r a t e and e f f i c i e n c y of gain and type e v a l u a t i o n . On the b u l l t e s t a t t h i s i n s t i t u t i o n the s i t u a t i o n arose that the i n s t a n t  aneous r e l a t i v e r a t e of gain and type e v a l u a t i o n were given a c o r r e l a t i o n c o e f f i c i e n t of - , G 0 J 4 6 . • 76 HEREFORD BULL RESEARCH PROJECT 1951^ 52 • Table 13 SCORES ASSIGNED TO ANIMALS BY GRADERS; JUDGE BULL N UMBER 1 2 3 4 5 6 .7 8 9 10 A 73 . 74 55 73 84 80 70 79 • 77 65 B 81 75.5 54 76 76 72.5 82 75 77 85 C 96 94 86 92 81 77 83 79 82 91 D 75 75 5T;5 66 64.5 63.5 66.5 69.5 67.5 68.5 E 72 75 58.5 70.5 65*5 62 69.5 65.5 69 67.5 F 74 85 57 66 . 68 65 73 69 76 76 G. 80 79 64 72 71 g7 77 72 68 78 TOTAL 551 557.5 426 515.5 510 487 ,521 509 516.5 531 AVERAGE • 78.7 79.7 60.8 73.6 72.8 69.6 74.4 72.7 73.8 75.'8 77 This l a c k of s i g n i f i c a n c e has been i n t e r p r e t e d as an assurance that a -breeder may exert a s e l e c t i o n pressure f o r a greater r a t e of gain without i n f l u e n c i n g type c l a s s i f i c a t i o n m a t e r i a l l y . This t h e s i s would take exception t h i s i n t e r p r e t  a t i o n however on the grounds that despite the r e s u l t s of s t a t i s t i c s i t i s not i n harmony w i t h b i o l o g i c a l observations. The f o l l o w i n g l i n e of thought may serve as an i l l u s t  r a t i o n . According to Gowen (1932), the best s i n g l e body measure of the milk producing p o t e n t i a l i t i e s of a cow i s her body weight, "...the l a r g e r the y i e l d , the l a r g e r the s i z e of the cow...." Body s i z e has long been known to be associated w i t h t h y r o i d a c t i v i t y which could have no b e t t e r reference than the work of Gregory (1950) on the dwarf c h a r a c t e r i s t i c i n beef c a t t l e . Thyroid a c t i v i t y I n d i r e c t l y i s a measure of p i t u i t a r y a c t i v i t y . P i t u i t a r y a c t i v i t y i s necessary f o r a la r g e output of the growth hormone. The work of B a i r d , Nalbandov and Norton (1952) i n d i c a t e s that the growth i n a s t r a a n of r a p i d growing swine as compared with a slow growing s t r a i n can be accounted f o r by .an increased content of growth hormone per u n i t of a n t e r i o r p i t u i t  ary t i s s u e . From the foregoing i t may be s a i d the " l a r g e r mature body s i z e and r a p i d growth must be asso c i a t e d i n the same animal." This i s contrary to the type s e l e c t i o n being p r a c t i s e d f o r the 78 show-ring standards which c a l l f o r a deep, compact, t i d y (not too l a r g e ) , smooth (excess f a t from e a r l y "breaking" growth curve), well-balanced ( e a r l y maturity a s s o c i a t e d w i t h a small mature weight), i n general an animal approaching the "comprest" type, g e n e t i c a l l y heterozygous; f o r the c h a r a c t e r i s t i c dwarfism which i s brought about by an i n a c t i v e t h y r o i d a s s o c i a t  ed with slow growth. A c o n s i d e r a t i o n of body s i z e seems necessary p r o v i d i n g i t can be demonstrated c o n c l u s i v e l y , . i e : q u a n t i t a t i v e l y that i t i s c l o s e l y a s s o c i a t e d w i t h r a p i d growth. I t has long been known and the f a c t u t i l i z e d that heart g i r t h measurements were a very good measure of body weight, and so might give an i n d i c a t i o n of the inherent growth a b i l i t y of an animal. This measure however could be an e r r o r because an animal c a r r y i n g high c o n d i t i o n and consequently having a l a r g e body weight and heart g i r t h , would have an apparent "growthiness" which a c t u a l l y may be e a r l y maturity, slow growth and an e a r l y l a y i n g on of f a t t y t i s s u e . I t would appear more reasonable that height at w i t h e r s , a measure of the s k e l e t a l s t r u c t u r e which i n t u r n i s a measure of s i z e and i s only a f f e c t e d by environment i n extreme cases would serve as an indexo of r a p i d growth. 79 The f i r s t impression may be that i t i s unnecessary to introduce another f a c t o r to measure growth r a t e which can be obtained from absolute weights, however i t has been pointed out e a r l i e r that r a t e of gain measured over any p e r i o d i n the growth phase i s l i a b l e to considerable e r r o r due to changing r e l a t i v e growth r a t e and so i t . may be desirable': to u t i l i z e a f i n a l weight as a standard by which an animal i s s e l e c t e d f o r a b i l i t y to grow. To e l i m i n a t e c e r t a i n animals a c h i e v i n g the f i n a l weight by excess f a t t e n i n g , the minimum height a t withers could be introduced. 80 (B) Wistar Rat Research P r o j e c t (1) I n t r o d u c t i o n As has been p r e v i o u s l y noted i n the preceeding s e c t i o n s there i s some evidence that animals tend to grow at an ac c e l e r a t e d r a t e f o r a per i o d f o l l o w i n g an increase i n energy int a k e preceded by a per i o d of sub-optimum n u t r i t i o n . The l i t e r a t u r e contains vague references to the n e c e s s i t y of an i n i t i a l feeding p e r i o d of 14 - 3 0 days as a pr e c a u t i o n  ary measure to avoid i n t r o d u c i n g a bias which might favor the animal w i t h a h i s t o r y of sub-optimum n u t r i t i o n . J u s t how adequately t h i s p r e l i m i n a r y p e r i o d c o r r e c t s f o r previous environmental a f f e c t s i s i n some doubt and wit h t h i s i n mind the f o l l o w i n g o b j e c t i v e s were l a i d out. (1) To determine the r e s u l t i n g growth p a t t e r n of r a t s which have been on lowered planes of n u t r i t i o n f o r v a r y i n g p e r i o d s . (2) To provide some very accurate and d e t a i l e d data on r a t e and e f f i c i e n c y of growth which i s not r e a d i l y a v a i l a b l e f o r study from other sources. (3) To determine the value of the l a b o r a t o r y r a t as m a t e r i a l f o r studying r a t e and e f f i c i e n c y of growth of the r e l a t i v e l y expensive and slow maturing beef breeds. T A B L E 15(a) COMPOSITION OF U.B.C. RATION No. 18 H u l l e d Oats 1050 l b s Ground Wheat 525 F i s h Meal 175 Meat Scraps 75 Skim M i l k Powder 50 A l f a l f a Leaf Powder ... 100 Steamed Bone Meal 20 S a l t g 2000 l b s Crude P r o t e i n (Nx6.25) . . 19.44 % 81 M a t e r i a l s and Methods: Nine l i t t e r s of the Wistar s t r a i n . A l b i n o r a t were se l e c t e d from the U.B.C. stock colony. They were weighed.', on the 3rd day and every other day f o l l o w i n g u n t i l the 21st day. •. No attempt was made.to i d e n t i f y the animals, but i t was soon obvious that the r a t s were d i f f e r e n t enough i n t h e i r body weights to allo w segregation i n t o i n d i v i d u a l growth patterns as i l l u s t r a t e d i n ATpp^ Lft:. (iA1-) A l l the r a t s were weighed on the 22nd day and 15 p a i r s of males were s e l e c t e d to meet the requir> ments of being l i t t e r mates and having as n e a r l y as p o s s i b l e the same .bodyhweight. A c t u a l l y a l l p a i r s were w i t h i n 2 grams of each other, i n body weight. The r a t s were todivli&ual'ly penned and weighed d a i l y from the 22nd day u n t i l they had a t t a i n e d a body weight of 200 grams. One animal of each p a i r designated by the l e t t e r "A" was considered the' c o n t r o l and waso.allowed a_d l i b i t u m U.B.C. r a t i o n 18, the stock r a t i o n of the colony, w i t h the a n a l y s i s shown i n Table 15 .(a) The opposite animals i n each p a i r , designated by the l e t t e r "B" were d i v i d e d i n t o three groups. Groups one, two and three received .70 per cent of the r a t i o n eaten by i t s T A B L E 15 AVERAGE FEED INTAKE PER DAY FOR PERIODS OF CONSTANT RELATIVE GROWTH AS INDICATED GRAPHICALLY Rat Weaning to 1st Break to Puberty to Body T o t a l Weaning Weaning to Increase to Ad L i b i t u m No. 1st break Puberty Weight of 200gms to 200gms 15 A 22-38 days, 9.4gms. 38-55 days , 14.3gms. 55-61 days , l6 .7gms. 22-61 days, 12.7gms. 15 B 22-34 " 6.3 " 34-60 " 10.2 " 60-68 " 15.5 M 22-68 10.1 » 22-49 days 39-53 11 13-8 " 22-58 7.3gms. 4 A 22-39 " 9.8 11 14 . 1 " 53 - 59 •• 12.1 » 41B 22-39 " 8.1 " 39-54 " 10.3 " 54-65 " 11.8 " 22-65 9.8 » 22-34 days 6.6gms. 8 A 22-36 " 10.0 " 36-51 » 14 .4 " ' 51v^6 " 16.6 " 22-56 12.9 " 8 B 22-37 " 6 . 5 " 37-47 11 13.0 " 47-62 " 15.4 " 22-62 11.5 " 22-37 days 1 A 22-36 " 10.1 " 36-51 " 13.9 " 51-55 " 15.3 " 22-55 12.4 " 6. 5gms. 1 B 22-39 " 7.1 " 39-52 " 11.9 11 52-62 » 13.7 " 22-62 10.3 "' 22-43 days 7.4gms. s 12 A 22-37 " 10.3 " 37-50 " 14 . 1 » 50-60 " 16.2 " 22-60 13.1 " 12 B 22-36 " 6 .8 " 36-60 » 9 .8 « 6O-77 " 14 . 1 " 22-77 10.4 " 22-55 days, 3'A 22-34 " 8,8 34-47 " 13.7 " 47-56 11 15.3 " 22-56 12.4 " 11.7gms. 3 B 22-49 " 8.3 » 49-62 " 14 .3 " 22-62 8.2 " 22-44 days 14 A 22-39 " 9.9 " 39-61 " 14 . 5 " 22-61 » 12.5 11 6.9gms. 14 B 22-42 " 8.0 ". 42-65 " 14 . 1 " 22-65 11 11.3 " 22-36 days 6.4gms. CD H 0) Rat Weaning to No.- 1st break 1st Break to Puberty 6 A 22-35 days, 7.8gms. 35-46 days, 12.5 6 B 22-42 " 6.5 " 42-52 " 10.3 13 A 22-30 " 7.6 » 30-50 " 11.8 13 B 22-32 " 6 . 5 32-71 " 7.0 11 A 22-38 " 10.2 " 38-49 " 13.4 11 B 22-47 " 6.6 " 47-66 " 8.2 10 A 22-30 " 8.1 " 30-54 " 10.2 10 B 22-29 " 5.9 " 29-47 " 6.4 7 A 22-36 " 9 . 5 " 36-50 " 14 . 5 7 B 22-40 " 6.8 " 9 A 22-37 11 10.8 " 37-50 " 15.0 9 B 22-42 " 8.5 " 42-55 " 13.8 2 A 22-34 » 10.7 " 34-46 " 14 .3 2 B 22-40 " 7.9 " 40-53 " 12.4 5 A 22-39 " 9.7 " 5 B 22-42 " 7.3 " Puberty to Body Weight of 200gms. T o t a l Weaning to 200 gms. Weaning to Increase to A d L i b i t u m 46-64 days, 15.. 2gms. 22-64 days, 12.2gms 52-71 " 13.1 " 22-71 " 9.9 " 50-62 " 15.4 " 22-62 " 12.0 " 49-61 11 8.5 11 22-61 . " 10.3 " 54-66 " 15.1 " 22-66 " 11 . 1 11 47-81 " 11.1 11 22-81 " 9 .0 " 50-55 " 17.6 " 22-55 " 12.8 " 40-68 " 11.8 " 22-68 ••• 9.8 " 50-62 '» 15.6 " 22-62 " 13.6 " 55-74 13.4 " 22-74 " 11.6 " 46-51 " 15.4 " 22-51 " 13.0 " 53-66 » 12 .5 " 22-66 10.6 " 39-57 " 14 . 1 " 22-57 " 12.0 " 42-61 " 13.4 " 22-61 " 10.3 11 22-48 days, 7.0gms. 32-71 days, 7.Ogms. 22-66days, 7.3gms. 22-59 days, 6.8gms. 22-54 days 7.8 gms. 22-38 days/ 7.8gm|. 22-41 days, 8.Ogms. 22-36 days, 5«3gms. C O 82 p a r t i c u l a r l i t t e r mate at the same body weight. Group one upon a t t a i n i n g a body weight of 70 grams was allowed the same r a t i o n as i t s p a i r at that body weight. Group two was increased to f u l l feed at 110 grams body weight and group three at 130 grams body weight. For f u r t h e r d e t a i l s of management reference i s made to the undergraduate essay of Amde Wondefrash (.1952). R e s u l t s and D i s c u s s i o n i F o l l o w i n g through the reasoning presented i n the preceding s e c t i o n s the data on the Wistar r a t s was p l o t t e d on semi-log graph paper and as would be expected the r a t s grew at a constant r a t e r e l a t i v e to body weight over c e r t a i n phases of the growth p e r i o d . Although only three a c t u a l p a i r s are presented g r a p h i c a l l y F i g u r e 18, 19? 20,' the "k" value f o r each p a r t i c u l a r phase of the growth p e r i o d w i t h i t s d u r a t i o n i n days i s presented i n .Table"l6..' Extensive t e s t s of s i g n i f i c a n c e were c a r r i e d out 'in the d i f f e r e n c e s i n slope of the r e p r e s s i o n l i n e over the same growth phase f o r the r a t p a i r s f o l l o w i n g the low intake i n d i v i d  uals r e t u r n to f u l l feed. R e s u l t s i n d i c a t e that a l l d i f f e r e n c e s are i n s i g n i f i c a n t , which prompts the f o l l o w i n g statement: BODY WEIGHT IN GRAMS BODY WEIGHT IN GRAMS BODY WEIGHT IN GRAMS T A B L E 16 ''K" Values And The P e r i o d Maintained i n Days For Male Wistar Rats Rat No. • B i r t h - l l d a y s 11-24 24-36 36-51 51- °A K = .0937 .0620 .0782 .0382 .0223 11-22- 22-37 37-47 47- ° B .0620 .0338 .0495 .0226 4A Birth - 1 3 d a y s 13-22 22-39 39-53 53- K ts .1310 .0641 .0732 .0341 .0267 39-54 54- 4B " " " .0271 .0128 Birth-lOdays 10-22 22-39 39- 14-A K = .1020 . 0532 . 0710 .03 08 22-42 42- 14B " " .0546 .0276 Birth-14days 14-22 ' 22-34 34-47 47- 3A K - .1130 . 0 6 1 0 . .0835 ,0456 .0266 22-49 49 49- 3B " •» .0359 .0269 B i r t h - l l d a y s 11-37 37-50 50- 12A K cn .0952 .0639 .0381 .0225 11-22 22-36 36-6O 60-12B •» .0639 .0591 .0310 .0153 Birth-12days 12-22 22-36 36-52 52- 1A K - .1390 .0741 .0679 .0339 .0183 22-3,9 39-50 50- 1B " " .0551 .0393 .0199 B i r t h - l l d a y s 11-22 22-38 38-55 55- 15A K - .1060 .0621 .0764 .0318 .0236 i5B - HsSll : : : : : ?8i28 Birth-22days 22-35 35-46 46- 6A K - .0759 .0845 .0605 .0223 , , 22-42 '42-52 52- n 6B " .0539 . 0404 . 02 58 B i r t h - l l d a y s 11-22 22-39 3 9 - 5A K = .1180 .0714 .0653 .0270 Birth-22days 22-42 42- 5B K = .0848 : .0693 .0323 Birth-14days 14-22 22-34 34-46 46- 2A K = .1230 .0629 .0785 .0433 .0298 22-40 40-53 53-2B » " ..0548 .0391 .0206 87 The male Wis&ar Rat has the a b i l i t y to grow at the same instantaneous growth r a t e r e l a t i v e to body weight as i t s ad l i b i t u m fed l i t t e r mate, when i t has been r a i s e d to f u l l feed, f o l l o w i n g a 30 per cent r e d u c t i o n i n food i n t a k e from weaning to 70, 110, and 130 grams body weight. Before attempting e x t r a p o l a t i o n from the Albino Rat to the beef animal, the r e l a t i v e s e v e r i t y of the r e d u c t i o n of food intake must be considered f o r the two species. The average age of a l l Group "A" r a t s at 200 grams body 'weight was 59 days and the body weight of Group "B" at t h i s age was 159 grams. The average body weight at weaning-was 39 so that Group "A" increased body weight l 6 l grams i n 37 days and Group "B" increased body weight 120 grams i n the same per i o d or 75 per cent of maximum. Reference to the work of Brody (194-2) i n d i c a t e s that the. period of 22 days to 60 days i n the r a t corresponds p h y s i o l o g i c a l l y to the p e r i o d - b i r t h to 10 months i n the cow. Maximum body weight expected of a group of steers has (cont. next page)-88 already been set down In the introduction to t h i s thesis and appears to be approximately 625 pounds at 10 months. 75$ of this, maximum would be I4.7O pounds and represents a difference ofo 5 pounds per day which i s as great as would be expected of calves being raised i n a pure bred herd. I t seems safe to state that the severity of the r a t i o n l i m i t a t i o n s imposed on the Wistar rats are of the magnitude which might be expected i n the h i s t o r y of certain b u l l s coming on to a performance test Previous to t h i s po&nt i n the thesis there has been no reference to the reasons f o r the changes i n r e l a t i v e growth rate oceuring i n the various species being studied. By r e f e r r i n g to figure 18 i t may be noted that with the passage of time and the increase i n body weight, there i s a decreasing r e l a t i v e growth rate. The reason f o r t h i s stated very simply i s that as the body mass increases the surface area per unit mass becomes larger by the power . 7 3 and so there i s less opportunity f o r growth by either the c e l l division.:: or c e l l accre&ibnu method because of population crowding much as i s experienced with b a c t e r i a l cultures. I t has been observed that when a growth phase shows an increase r e l a t i v e growth rate over the proceeding section some factor has been l i m i t i n g during the e a r l i e s t period. This phenomenon may be noted,in fig u r e .,19 i n which the control r a t grew at an increased rate following 89 weaning since energy int a k e was l i m i t i n g while nursing the dam. The f i r s t change i n r e l a t i v e growth i n the r a t at 10-11 days f o l l o w i n g b i r t h may be s a i d to be the po i n t when energy intake i s l i m i t e d by the mi l k production of the dam. A simple c a l c u l a t  i o n on the p o s s i b l e energy requirement of a l i t t e r a t t h i s p o i n t w i l l demonstrate that i t i s impossible f o r the,female to consume enough energy to produce the necessary milk (Waldern & Wood 1952). This m i l k shortage i s p e c u l i a r to the multiparous animals but i t has a counterpart i n the growth of beef calves when the capacity of the c a l f l i m i t s the energy Intake i n the form of milk. This s i t u a t i o n however can only occur when the cow has the p o t e n t i a l and a v a i l a b l e energy to exceed i n pro d u c t i o n the a p p e t i t e of her c a l f . The next main a l t e r a t i o n i n r e l a t i v e growth r a t e i s at 21 days or weaning and as al r e a d y observed there may be an increased r a t e due to the increase i n a v a i l a b l e energy. The change i n growth r a t e which occurs at about 30-4-0 days i n the r a t i s d i f f i c u l t to e x p l a i n . The growth data on the Wistar r a t s were subjected to s t a t i s t i c a l a n a l y s i s to f i n d the c o r r e l a t i o n , i f any, between, the r a t s A and B of each p a i r when t h e i r age or th©ir body weight were considered at the p o i n t of the c h a r a c t e r i s t i c a l t e r a t i o n s i n r e l a t i v e growth r a t e that appear twice f o l l o w i n g weaning.. Unfor t u n a t e l y a l l the c o r r e l a t  i o n c o e f f i c i e n t s were i n s i g n i f i c a n t although i t would appear that there was a trend towards the changes In growth r a t e to occur more at a constant body weight than at a constant age. 90 The lack of significance may be attributed mainly to two f a c t o r s . (1) The numbers are not great enough to correct for the wide variations that e x i s t between individuals even i n smch an inbred group of animals as considered. (2) Physiological age although usually closely correlated with body weight i s not necessarily controlled by i t and the neuro-endocrine drive to mature w i l l eventually force p h y s i o l o g i c a l ageing despite complete cessation of growth i n the body weight sense. A consideration of the second change i n r e l a t i v e growth rate following weaning has been made by many investigators and i t i s usual to term i t the "pubertal break" since i t coincides with the onset of sexual maturity. There are other factors than simple sexual maturity however involved i n t h i s marked slowing i n growth rate. McMeekah (19^4-2) observed i n h i s work with swine that the stomach and small i n t e s t i n e reached t h e i r greatest percentage of t h e i r weight at b i r t h by 2i(. weeks of age which i s puberty for t h i s species. The significance of t h i s factor i s obvious since food intake w i l l not increase and ttfiile basal, metabolism and maintenance requirements w i l l continue to increase there w i l l be a decreasing amount of nutriants available f o r growth. Another factor which may be Involved i s that the percent age body f a t becomes greater than the percentage body protein at t h i s point with the consequent high energy requirement per unit gain as previously described. 91 As an additional point of i n t e r e s t the heritab i l i t y of body weight of the rats at 60 days of age was c a l  culated as a f u l l sib c o r r e l a t i o n . The figure obtained was 6,8% which indicates that there would be l i t t l e advantage i n selecting animals from the same l i t t e r over those from d i f  ferent l i t t e r s i n the highly inbred stock colony at the University of B r i t i s h Columbia 92 III Summary and Conclusions Two approaches to the problem of assessing merit i n beef c a t t l e have been elaborated upon i n the present work. The f i r s t approach has been made f o l l o w i n g a post  e r i o r i reasoning. I n v e s t i g a t o r s have attempted to provide themselves w i t h . l a r g e amounts of data which presumably would lend i t s e l f to extensive s t a t i s t i c a l manipulation. Unfortun a t e l y undue r e l i a n c e i s placed on s t a t i s t i c a l a n a l y s i s of the f i n d i n g s without s u f f i c i e n t regard f o r p r i n c i p l e s of b i o l o g y . The second approach to the problem which has a t t r a c t e d the m i n o r i t y of researchers to date u t i l i z e s a p r i o r i reason i n g . I n t h i s approach fundamental f i n d i n g s i n r e l a t e d f i e l d s such as biochemistry and physiology have been used to e s t a b l i s h working hypothesis i n an attempt to e x p l a i n the v a r i a t i o n s i n the r a t e a n d . e f f i c i e n c y of gain of t e s t . a n i m a l s . As has been shown e a r l i e r these two approaches appear to be I r r e c o n c i l a b l e . This seems so since the popular approach 93 can lead to i n v a l i d conclusions from what appears to be s t a t i s t i c a l l y v a l i d data. From the work c a r r i e d out here as w e l l as that provided i n the l i t e r a t u r e the f o l l o w i n g t e n t a t i v e conclusions have been drawn. . ' (1) Animals tend to grow at a constant r a t e r e l a t i v e to body weight over c e r t a i n p o r t i o n s of t h e i r growth curve. (2) Rate of gain must be considered on a weight constant b a s i s . (3) The d i f f e r e n c e s i n r a t e and e f f i c i e n c y of gain which have been observed between s i m i l a r animals maintained under i d e n t i c a l c o n d i t i o n s i s mainly due to the type of t i s s u e •> growth being made. (4) Rate of gain measured over time i n t e r v a l other than instantaneous may introduce an e r r o r which i s as great as the d i f f e r e n c e s observed between t e s t animals. (5) Animals considered at any but the same body weight may provide biased r e s u l t s which can be i n e r r o r as much as the d i f f e r e n c e s observed between t e s t animals. (6) D e t a i l e d s t u d i e s of growth must i n c l u d e a con s i d e r a t  i o n of the data treated as.the r e g r e s s i o n of the 94 logarithm of body weight on time. (7) The feeding of beef b u l l s on t e s t should f o l l o w a schedule i n which the animals r e c e i v e something l e s s than they would under ad l i b i t u m c o n d i t i o n s . (8) The r a t i o n fed to beef b u l l s on t e s t must f i r s t be balanced as to roughage and concentrate so that bulk does not l i m i t the energy intake ''or the i n t a k e of other n u t r i e n t s r e q u i r e d to permit optimumi' growth. (9) On the basis of present r e s u l t s there i s no j u s t  i f i c a t i o n f o r the i n c l u s i o n of a l i v e animal score i n an index of merit f o r beef c a t t l e . (10) There i s no s i g n i f i c a n t d i f f e r e n c e ,between the instantaneous r e l a t i v e growth rates of Wistar Rats fed ad l i b i t u m on balanced r a t i o n and those fed ad l i b i t u m f o l l o w i n g a r e s t r i c t i o n to 70 per cent of ad l i b i t u m f o r 70, 110, and 130 days f o l l o w i n g weaning. IV - APPENDICES- Wistar Rat Body Weight and Feed Consumption Data (a) B i r t h to Weaning (b) Weaning to 200 grams 96; Body Weight i n Grams L i t t e r No. 1 Males Age' • Mean Days 1 2 3 4 5 6 7 8 9 Weight ' 3 /' 5 10.9 10.6 10 .5 10.0 10 .0 10.0 • 9 .9 9 .8 9.2 10.1 7 13 .0 13 .0 13 .0 12.9 12.8 12.5 12 .0 12;.0 11.5 12.5 9 16.4 16 .0 15.1 14 .7 14 .7 14 .7 14.6 14 .2 14 .0 14 .9 11 18.4 18.4 18-.0 18.0 17.3 17.0 17.0 16.9 16.3 17.5 13 2 0 . 5 2 0 . 0 2 0 . 0 19 .5 19 . 5 19 .5 19 .5 18 .9 18 .1 19 .5 15 23.4 22.7 22.7 22.4 22.2 2 2 . 0 21.8 21.4 20.9 22 .1 17 25 .5 25.3 24 .7 24.4 24 .3 24.2 24 .0 23.3 23 .1 24 .3 19 27.6 26.8 26 .8 2 6 . 5 26.2 26 .1 2 6 . 0 2 5 . 5 24 . 1 26 .2 21 32 .9 32.4 31.3 31.2 30.4 3 0 . 9 3 0 . 0 28.7 26.4 3 0 . 5 22 34 .0 34 .0 3 3 . 0 3 3 . 0 3 2 . 0 3 2 . 0 31 .0 31 .0 2 8 . 0 3 2 . 0 Test Rats 13A 13B 14A 14B Females Age - Mean Days 1 2 3 Weight 3 5 10 .0 9.6 8.7 9.4 7 12.2 11.2 11.2 11.5 9 13.9 13.3 H . 2 12.8 11 17.0 17.0 15.7 16.7 13 19.1 17.6 I 6 . 3 17.7 15 21.3 2 0 . 0 19.6 20.3 17 22.7 21.7 20.-6 21.6 19 25 .1 22.8 21.6 23.2 21 30.1.27.3 25.9 27 .8 22 Weaned 97 L i t t e r No. 2 Body Weight i n Grams Females Males Age Days 1 2 3 4 3 9.3 8.8 7.3 6 . 8 :-5 11.2 11.2 , 9 . 5 8 . 5 7 14.2 14 .2 10.2 12.2 9 19.2 18.7 14 .9 13.1 11 • 24 .5 22.8 18.0 16 .0 13 28.8 27.3 2 2 . 0 19.0 15 32.7 31 .4 26.2 21 .5 17 37.2 3 6 . 5 2 9 . 5 25 .0 19 42 .2 40 .5 3 4 . 1 29.2 21 47.4 4 5 . 5 40 .2 31.8 22 Weaned Tefft Rats 1 10.0 7.3 7.2 12.4 9.3 8 .4 15.8 11.9 11.4 21 .0 14 .0 14 .0 25.7 17.8 17.8 3 0 . 0 2 0 . 5 2 0 . 5 34.3 24 . 1 23.7 39 .1 2 9 . 0 28.7 44 .5 3 2 . 7 31.9 49.9 3 7 . 7 3 6 . 0 6B 6A ( 98 L i t t e r No. 3 Body Yfeight i n Grams Days 1 2 1 2 3 4 5 6 7 8 9 5 9 . 1 8 . 9 1 0 . 0 1 0 . 0 9 . 7 9 .3 9 . 3 '9.3 8 . 9 8 . 7 8 . 4 7 1 0 . 3 1 0 . 0 1 2 . 7 1 2 . 5 1 2 . 5 11 .8 11 .5 1 1 . 0 1 0 . 9 . 1 0 . 3 1 0 . 0 9 13.2 1 2 . 6 15 .0 14 . 8 14 . 5 14 . 5 14 . 1 1 3 . 6 13 .4 1 2 . 4 11 .7 11 1 6 . 4 14 . 8 1 8 . 5 1 7 . 8 1 7 . 5 1 7 . 0 1 6 . 7 1 6 . 7 15 .7 15 .4 14 . 9 13 1 8 . 8 1 7 . 1 2 0 . 2 , . 2 0 . 2 2 0 . 0 19.8 1 9 . 4 1 9 . 4 18.5 17.6 16 .6 15 2 2 . 4 2 0 . 0 24 .6 23.6 2 3 . 5 2 3 . 5 2 2 . 4 2 2 . 3 2 1 . 2 2 0 . 7 1 9 . 6 17 2 3 . 7 2 2 . 3 2 7 . 2 2 6 . 4 2 6 . 2 25.9 25 .5 24 . 9 24 . 5 2 3 . 8 2 2 . 0 19 2 8 . 9 23.9 3 0 . 3 2 9 . 8 2 8 . 9 2 8 . 7 2 8 . 5 2 8 . 5 2 7 . 0 2 6 . 1 25 .6 21 3 3 . 4 2 5 . 0 3 6 . 4 36.I 3 4 . 4 3 3 . 8 3 3 . 8 3 3 - 0 31 .2 3 1 . 0 3 0 . 3 Test Rats 8A 8B 11B 12A 11A 12B 15B 15A L i t t e r Wo.4 Age Body Weight i n Grqms Females Males Days 1 2 . 3 4 1 3 9.4 8.8 8.2 8 , 0 8.8 5 12.2 11.9 11.0 10 .0 11.8 7 16.1 15.4 14 .8 12.8 15.4 9 19 .7 19.2 18.5 17.0 2 0 . 0 11 24 .1 23.5 23.2 21.7 24 .5 13 28.9 2 8 . 0 . 2 6 . 7 25.4 2 9 . 0 15 32.3 - 31.6 31.7 3 0 . 0 33.6 17 36.6 36.3 3 5 . 5 3 3 . 7 • 3 8 . 7 19 41 .2 41 .0 40 .2 3 8 . 1 42 .4 21 48.4 4 8 . 4 46.8 4 4 . 7 49.9 22 Weaned 4 . 5 Dead 100 L i t t e r No. 5 Females Body Weight i n Grams Age Days 1 2 3 4 5 6 7 8 9 3 8.3 . 8 . 0 7.8 7.8 7.7 7.7 7.3 7.3 7.2 5 10.0 10.0 10.0 10.0 9.7 9.2 9.1 9 . 0 8 .7 7' 12.1 12.0 11.9 11.4 11.2 11.2 11.0 10.8 10.2 9 15.5 14 .5 14 .2 13-6 13.5 13.3 12.7 12.6 11.9 11 17.8 17.7 17.6 17.3 16.4 16.2 16 .2 ' 15.4 14 .5 13 19.4 19.1 19.0 18.7 18.1 18.0 17.5 17.5 16.7 15 21.8 21.7 21.6 21.6 20.9 20.7 2 0 . 7 19.9 14.6 17 2 5 . 5 24 .5 23.9 23.3 23 .1 22.8 22.3 21.9 20.4 19 2 8 . 0 27.2 25.7 2 5 . 5 25.3 25.3 24 .9 23.4 22.1 21 31.8 31 .0 30.2 3 0 . 0 29.7 29.2 2 9 . 0 2 8 . 5 25 .0 22 Weaned Males 3 8 . 0 7.9 7.7 7.7 5 10.1 10 .0 9.8 8.9 7 12.6 12.. 6 12.4 10.9 9 15.5 15.4 15.3 12.4 11 19.3 19 .3 18.8 15.5 . 13 22.1 21.3 20.4 17.5 v 15 24 .3 22.4 2 2 . 5 2 0 . 0 17 2 7 . 0 25 .7 24 .9 22.8 19 29.2 27.8 . 26.6 23.1 21 Test Rats 33.8 9A 3 2 . 5 9B 32.2. 28.9 101 L i t t e r Wo. 6 Body Weight i n Grams Females Days 1 2 3 4 5 . 6 7 8 9 3 8 . 8 8.7 8.6 8.5 8.4 8.3 8.2 8 . 0 7 . 4 7 . 2 5 11 . 0 10.8 10.4 10.3 10.2 10.0 9.9 9.6 18.6 8.6 7 13.7 12.6 12.5 12.4 12.4 12.3 11.9 11 . 7 10.7 9.9 9 16.5 16.1 15.9 15.8 15.7 14.6 14.3 14.1 12.3 11.3 1 1 2 0 . 0 19.5 19.1 18.7 17.4 16.2 16.1 1 5 . 8 14.7 12.9 13 , 22.2 21.6. 20.9 , 2 0 . 8 20.5 20.1 19.5 I8.3 1 6 .5 15-3 15 24.4 24.3 24.1 23..4 23.2 22.1 21.5 18.2 18.0 16.5 17 27.3 26.3 25.7 25.1 24.9 23.4 • 23.1 21.2 2 0 . 0 18.I" 19 30.5 3 0 .1' 29.4 29 .0 28.6 26.2 26.2 24.6 22 . 8 20.8 21 ' 3 4 . 4 33.6 33.3 33.2' 3 2 . 0 30.5 29.8 28.4. 26.7. 23.4 22 Weaned Males Age Days 1 2 3 4 5 3 9.3 9.2 8.9 8.7 8 . 7 5 11 .6 11 . 1 11.1 10.8 10.1 7 15.0 14.4 14.1 13.5 12.6 9 18.1 17.8 16.8 16.6 14.9 11 21.3 20.2 2 0 . 0 19.3 18.4 ' 13 22.8 22.0 21.9 21.8 20.8 1 5 26.3 24.7 24.1 23.5 2 3 . 0 17 28.0 27.2 26.3 26.3 25.7 19 3 2 . 6 29.9 29.7 28.9 28.3 21 36.8 34.5 33.8 33.5 32.6 22 Weaned Test Rats 7A 7B 10A 10B 102 L i t t e r NO. 7 Body Weight i n Grams Females Males Age Days 1 3 4 1 3 4 5 3 7.6 7.4 7.4 7.0 7.9 7.6 7.2 7.2 7.2 5 9.7 9.7 9.6 8.7 9.9 9 .8 9:6" 9.5. . 9 . 2 7 12 .6 12.1 12 . 0 11.9 12 .6 12 .4 12 .2 11.1 . 11.0 9 15-7 15.7 15.7 15.5 15.9 15.6 15.6 13.4 13.4 11 20 .3 20 .2 1818 16 .8 20 . 0 20 . 0 19 . 7 16 .5 15.1 13 25.0 24 .3 21.6 20 .3 24 .6 24.^ 23.3 19 .3 17 .9 15 30.3 29.3 26 .4 23.4 28 . 7 28 . 5 26 . 7 21.8 20 .2 17 3 5 . 0 33 .7 3 0 . 0 28.4 31.9 31.7 31.3 26 .7 28.7 19 40 .3 3 9 . 5 36.2 33 .1 3 7 . 0 36.3 36 .2 3 0 . 7 28.7 21 45.4 44 .9 40 . 4 37.6 42 . 7 42 . 7 40 . 4 37 .1 3 3 . 1 22 Weaned Test Rats 4A 4B 5B 5A 103 L i t t e r Wo.8 Body Weight i n Grams Age Days 1 2 3 4 5 1 2 3 4 5 4 1 10.4 9.6 9.4 9.2 9.0 11.0 10.2 9-7 8 .5 8 .5 6 13.8 11. -8 11.7 11.6 11.0 13.1 13.1 12 .5 10.5 10.3 8 14 . 5 14.0 13.8 12.8 12.1 16.9 16.6 15.9 15-5 12.4 10 20.4 17 .8 16.7 16.2 14 . 5 19.4 1 9 . 1 1 8.4 14 .8 13.4 12 24.1 20.1 19.7 18.8 17.4 23.0 22.7 22 . 5 15.4 15.4 14 2 8 . 5 23.7 22 .8 22.1 20.4 29.0 25.6 25.2 16.4 - 16 33.4 27.2 25.9 25.4 23.0 31.2 30.0 28.4 17.7 18 38.O 30 .9 29.8 29.3 25 .5 3 5 . 5 34.2 33.2 15.6 20 44.7 37.4 34.7 34.1 30.0 42 . 5 40.2 3 9 . 7 14 . 5 22 51.8 43.4 40.1 40 . 9 3 6 . 5 4 9 . 8 48,7 46.0 - 23 Weaned 52.0 51.0 50.0 104 Body Weight i n Grams L i t t e r No. 9 Age Days 3 7.1 7.0 6 .5 6 . 5 6 .1 5.7 5 8.6 8.9 7.9 7.5 7.4 7.3 7 13.1 10.0 9.8 9.8 9 . 5 8 . 5 , 9 12.3 11.5 11.2 11.0 9.2 8.9 11 19.4 16.2 10.0 / — — 13 21.2 2 0 . 1 14 . 0 15 26.4' 24 . 0 18 .5 17 31.3 29.2 24 . 0 19 35.7 31.9 2 8 . 0 21 39 .8 37.8 3 6 . 0 22 Weaned Age Days 3 8.0 7.9 7.6 7.6 7.6 7.5 7.3 7.1 5 9.8 9 . 5 9 .5 9.4 9.3 9 . 3 ' 9.3 9.0 7 12.8 11.9 11.9 11.1 11.1 11.1 11.1 10.1 9 15.6 15.5 15.4 14.8 14 . 6 14.4 12.6 11 22.5 20.6 20.0 19.2 18.7 18.4 — 13 27.3 25.8 25.0 24 . 7 23.4 22.4 15 32.2 31.2 30.3 29.8 28.7 27.0 17 37.7 3 5 . 5 3 5 . 5 32 .9 32 .9 32.2 19 42.8 40 .6 3 9 . 0 38.4 37.8 32.9 21 47.6 47.3 44.6 43.0 41.8 35.9 22 50.0 50.0 48.0 48.0 45.0 45.0 Weaned Test Rats IA .IB 2A 2B 3A 3B 10$ U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T cjPFr.iFs Wistar Rat A S S A Y E R / G. M. W.  D A T E 2.2nd Day D A T E 23rd Day n A T F 2 4 t h ;Day D IE T A N IM A L N U M B E R  ID E N T IF IC A T IO N  X Ul V) j| W E IG H T O F  A N IM A L 1 F E E D  O F F E R E D  CO z Ul 1- < Ul O Ul Ul u. OTIS T O T A L  F E E D  ' C O N S U M E D  T O T A L  W E IG H T G A IN E D  n : | W E IG H T O F  A N IM A L | F E E D  O F F E R E D  z Ul 1- < UJ • Ul Ul u. amp, T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T G A IN E D  3 W E IG H T O F  A N IM A L | F E E D  O F F E R E D  z Ul 1-< ; Ul Q Ul Ul U. .eriifi<: T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T G A IN E D  U.BvG . Ration #18 IA ] aale ^0 5 1 45 10 1 •50 10 9- 2 « 48 5 1 45 :.io 4 47 10 9 3 - 45 5 3 37 10 3 44 10 7 4 H 45 5 0 35 10 4 38 10 7 5 -> 40 5 1 40 : 10 3 4^ 10- 7 M E A N 6 » 37 5 . 1 32 10 3 30 10 5 7 39 5 1 36 10 4 38 10 8 8 38 5 3 38 10 4 40 10 9 9 » 36 5 1 31 10 4 35 10 8' 10 » 36 5 4 36 10 5 40 10 9 n 35 5 3 33 10 5 35 ' 10 ' 8'" M E A N 12 » 36 5 2 35 10 5 37 10 8 1? 34 5 2 32 10 5 36 10 8- 14 » 33 5 - 4 33 10 6 35 10 9 15 32 5 4 32 10 6 34 10 7 M E A N M E A N 106 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wistar Rat A S S A Y E R _ D A T E 2Sth Day D A T E 26th Day H A T E 27th Day D IE T A N IM A L N U M B E R ID EN TI FI CA TI O N X Ul V) 3 W EI G H T O F A N IM A L q 3 FE E D  O FF E R E D  0 z Ul < Ul Q Ul Ul u. fX,TT]S TO TA L FE E D  C O N SU M E D  TO TA L W EI G H T G A IN E D jj W E IG H T O F A N IM A L _ FE E D  O FF E R E D  3 ....  z Ul 1- < Ul • Ul Ul u. s am " TO TA L FE E D  C O N SU M E D  TO TA L W EI G H T G A IN E D q 3 W E IG H T O F AN IM AL  a 3 FE E D  O FF E R E D  ^ FE E D  E A TE N n -. —  TO TA L FE E D  C O N SU M E D  TO TA L W E IG H T G A IN E D U.B.C. Ration #18 IA nale 53 11 10 57 17 8 61 12 10 ? 52 10 10 55 17 10 6C 12 12 3 M 41 8 8 45 14 8 43 9 9 4 II 40 8 8 44 : . i3 8 48 10 10 II 45 9 7 50 15 8 53 11 10 M E A N 6 •I 51 6 :e 32 1C 7 37 7 7 • 7 43 9 9 46 14 9 5C 10 10 8 42 » 8 8 45 1M 9 52 10 10 Q „ 39 8 8 43 13 10 47 9 9 "10 II 43 9 o 48 14 9 53 10 9 " .1 -r: 11 II ^7 7 7 40 1? 10 4 C 9 9 M E A N 1? II 40 8 8 45 14 9 4£ 10 • 10 13 .. 39 8 8 43 1* 9 4£ 10 10 14 II 38 8 8 42 1^  9 4^ 9 9 15 II 37 7 7 34 1C 8 4C 8 8 M E A N M E A N 107 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wistar Rat , A S S A Y E R C . .M. .¥. .  D A T E 28 th D'av H A T F 29th Day H A T E 30th Day D IE T A N IM A L N U M B E R  ID E N T IF IC A T IO N  X LU U) &  W E IG H T O F A N IM A L CO  j§  F E E D  O F F E R E D  z LU < LU O LU LU b. T O T A L F E E D  C O N S U M E D  T O T A L W E IG H T G A IN E D  3 W E IG H T O F A N IM A L CQ  0 LU X LU LL LL. 0 Q LU LU IL Z LU 1-< Ul D LU Ul U. puis T O T A L F E E D  C O N S U M E D  T O T A L W E IG H T G A IN E D  < z < LL 0 f- I o ui 5 ms • Ul Lt LU U. li. 0 Q Ul LU U. Kms g F E E D  E A T E N  CQ  T O T A L F E E D  C O N S U M E D  T O T A L W E IG H T G A IN E D  U.B.C. Ration #18 IA male 65 16 12 71 18 12 77 19 13 ? i i 62 16 14 70 18 13 78 20 14 3 ii 50 13 12 56 14 10 62 15 12 4 it 51 13 8 55 14 11 61 15 10 5 tt 58 15 11 63 16 10 68 17 12 M E A N 6 tl •40 10 8 43 11 9 47 12 9 7 It 55 14 12 60 15 10 65 16 10 8 II 55 14 11 - 59 15 11 64' 16 11 9 II 50 13 13 55 14 12 61 15 13' 10 tl 55 14 11 6C 15 9 65 16 • 10 11 II 50 13 11 54 14 10 59 15 10 M E A N IP tt ^2 13 11 57 14 10 62 16 11 13 It 52 13 10 57 14 9 61 15 10 14 II 49 12 9 52 13 10 57 14 10 15 43 11 10 46 12 10 54 14 11 M E A N M E A N 1Q3, U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T s P F n P s - WISTAR RAT W.; A S S A Y E R C- M>. W. D A T E 31st Day ' n A T F 32nd Day R A T F 33rd Day D IE T 't i Ul ' m z • 3 Z : -1 < 1 s z < ID EN TI FI CA TI O N ] X Ul If) ^ W E IG H T O F A N IM A L i • Ul X Ul - u, u. 0 0 Ul ' Ul u. gnu z- t-< Ul D ,141 • Ul Ii. i gm TO TA L FE E D  C O N SU M E D  TO TA L W EI G H T G A IN ED  < z. z < U. 0 1 1-I 0 Ul 5 1 gm: (t o FE E D  O F F E R E D  B z Ul < ; Ul • Ul Ul u. 3 gm; TO TA L FE E D  C O N SU M E D  TO TA L W EI G H T G A IN ED  3 W E IG H T O F A N IM A L CQ  Q Ui K Ul ' U. U. . 0 Q .Ul Ul gms Z -UI < Ul a Ul Ul u. gms TO TA L FE E D  C O N SU M E D  TO TA L W EI G H T ' G A IN E D U.B.C. Ration #18 IA mal i 82 21 13 87 22 12 93 19 14 2 ti Qk 21 iV 88 22 13 95 19 14 3 II 66 17 14 72 18 5 79 16 14 l l II 16 11 69 17 12 75 15 12 5 n i i 18 12 78 20 12 81f 17 11 M E A N B » 50 13 12 55 14 11 6o: 12 12 7 n 7Q 18 11 75 19 12 80 16 12 8 II 69 17 13 76 19 13 83 17 11 9 II 66 17 13 70 18 15 75 15 14 10 n 68 17 10 70 18 7 72 14 ' 8 11 it 6^ 16 12 69 17 13 76 15 12 M E A N 12 t i 67 18 13 70 18 13 75 15 12 13 i i 6< 16 7 70 18 9 73 15 9 4" II 6c 15 11 65 16 11 70 14 12 15 II 56 15 12 63 16 12 68 14 11 1 M E A N * - M E A N U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C | E S_WISTAR_RAT__ A S S A Y E R C. M. W. D A T E 34 th Day H A T F 30th Day n A T P 36th Day D IE T A N IM A L N U M B E R ID EN TI FI CA TI O N X Ul <n < z < u. 0 1- I (3 U gms ?j FE E D  O F F E R E D  z • Ul h < Ul o Ul Ul IL ' . gm; T O T A L FE E D  C O N SU M E D  TO TA L W EI G H T G A IN E D < z < l i . 0 y- x 0 Ul gms [g FE E D  O F F E R E D  rn z Ul 1-< Ul 0 Ul Ul u. gms TO TA L FE E D  C O N SU M E D  TO TA L W EI G H T G A IN ED  g W E IG H T O F A N IM A L (j|  F E E D  O F F E R E D  z Ul 1-4 Ul Q Ul Ul u. j gm TO TA L FE E D  C O N SU M E D  T O T A L W EI G H T G A IN E D U.B.C Ration # 18 IA 11 iale 20 Iii 106 • 21 12 .10 22 lk~ 2 n 103 21 16 10C i 22 13 -i4 23 12 p 3 tt 8<i 17 15 9^  . 18 12 93 19 13 )l it 8Q 16 l l 8* > 17 10 90 18 13 • 5 ti 9C 18 13 9< > 19 12 L00 20 12 M E A N 6 ii 6< 13 12 70 10 73 15 13 7 » 87 17 13 93 19 12 98 20 13 8 n 88 18 Ik 93 19 13 .00 20 14- 9 ti 81 16 lif 8-J 17 13 90 18 15 10 n 74 15 10 79 16 19 80 16 10 Ll ti 82 16 12 86 18 13 92 18 14 M E A N L2 II 83 17 13 8 1 17 13 92 18 12 13 tt 76 15 10 8(1 16 7 &k 17 8 111 ti 75 15 10 8; 16 11 85 17 12 • tt lk 15 9 8c 16 11 84 17 13 M E A N M E A N a i o U N I V E R S I T Y Q F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T .pmp. WISTAR RAT A S S A Y E R C» M. W.  D A T E 3 7 t h D a y D A T E 37 t h D a y D A T E 37th D a y D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul tn -i < Z < U. 0 1- X 0 111 gms Q Ul • X Ul u. u. 0 o Ul 111 LL gms z Ul 1- 4 Ul Q Ul Ul u. gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  J < Z < LL 0 1- X Ul gms || F E E D  O F F E R E D  z Ul 1- - 4 Ul Q Ul Ul u 1 gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  4 z 4 LL 0 1- I Ul gra: (g F E E D  O F F E R E D  z Ul 1- 4 Ul 0 Ul Ul U. 3 gm -m T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U . B . C . R a t i o n # 18 ]L A I l a l e 115 23 14 12C > 24 14 12$ 25 14 2 tt L21 A • -3 121 i- 25 13 128 26 16 3 tt LOO 20 : .2 ioi L 21 12 108 22 14 4 tt 96 19 • -3 10 ) 20 12 106 21 14 tt L07 21 : -3 11 3 23 11 117 23 16. M E A N 6 i t 79 16 ; .2 8, \- 17 12 90 18 15 7 It LOif 21 : 11 ) 22 11 lU* 23 16 8 II L05 21 : r L l 11 L 22 13 118 24 14 9 tt 98 20 : L5 10 L 20 16 108 22 16 10 II 86 17 : L0 9 118 9 93 19 7 11 t l 99 20 : lk 14 3 21 11 110 22 13 M E A N 12 II 98 20 b 10 2 2.C 14 10L 22 17 13 It 90 18 LO 9 3 19 11 99 20 12 lk It 91 18 13 96 19 14 102 20 14 1$ II 90 18 L2 94 19 13 10c 20 14 M E A N M E A N 1X1 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L ' H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S ,VISTAR RAT A S S A Y E R C - M - W - D A T E 1 (.0th Dav H A T E [(.1st Day D A T E 42nd Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X HI V) < z < u. 0 i - i 0 111 gms • Ul IT Ul U. IL 0 Q Ul Ul u. gms z Ul h < Ul • Ul Ul u. T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3*  W E IG H T  O F  A N IM A L  CO  j|  F E E D  O F F E R E D  z Ul < Ul Q Ul Ul U. OTIS T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  < z < u. 0 H I 0 111 gms 2 F E E D  O F F E R E D  3 H F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration # 18 IA mali 127 25 13 133 27 i4 i4c I 28 12 2 n 136 27 16 Hp. 28 15 14C i 30 13 3 I I 115 23 14 119 24 14 12« > 25 16 J l # 111 22 11 l l 6 \ 23 13 12! > 25 10 f 5 it 12)| ?5 1 3 126 25 8 11< I 24 4 M E A N 6 ti 94 19 11 100 20 13 101 1 22 12 7 it 120 ?\\ 1 3 12«j 25 i4 13< 1 27 13 8 tt 119 2k 14 125 25 15 132 > 26 15 9 tt 110 22 13 11= 23 14 12( ) 24 14 10 I I 90 18 8 95 19 9 10( ) 20 9 11 tt i l l 22 13 116 23 12 12( ) 24 14 M E A N 12 ti 109 22 13 115 23 13 11< ) 2i|: 14 1 3 t! 100 20 11 10' 21 9 IK ) 22 15 I I 10l| 21 n n c 12 n : . 22 12 1 15 tt 103 21 10 107 21 13 n : . 22 14 M E A N M E A N • U N I V E R S I T Y O F B R I T I S H C O L U M B I A LABORATORY OF ANIMAL NUTRITION DEPARTMENT OF ANIMAL HUSBANDRY A S S A Y D A T A S H E E T SPECIES HTKTAR RAT ASSAYER -C. M. W.  DATE 43rd. Day n A T F -414-th Day RATF 45th Day DI ET  AN IM AL  N UM BE R ID EN TI FI CA TI ON  X Ul (A -i < z z < U. o .  H I u ui gms Q Ul X Ul u. u. 0 Q Ul Ul U. gms z Ul 1- < 111 0 Ul Ul u. gnu TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  -i < z z < u. 0 1- I 0 Ul gms g FE ED  O FF ER ED  z Ul < Ul Q Ul Ul u. 1 em! TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  g WE IG HT  O F A NI MA L | FE ED  O FF ER ED  to S FE ED  E AT EN  DO TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  U.B.C. Ration No 18 . IA nale 11L6 30 14 153 30 12 > 30 16 2 155 31 15 162 32 16 1 16c » 34 14 • 3 » 138 28 15 141 28 13 141 - 29 14 if it 130 26 14 135 27 14 14^  > 28 12 5 II 112 22 14 135 27 15 i4c i 28 14 MEAN 6 it 113 23 14 119 24 12 12' > 25 14 7 II 138 28 15 144 29 15 14* S 30 111 8 II 136 27 16 145 29 14 14^  1 30 —™^—-14 9 it 126 25 15 132 26 10 12; ! 24 15 10 it 101 20 9 107 21 11 11] . 22 10 11 it 126 25 14 132 26 14 13 c ' 27 13 MEAN 12 n 125 25 15 132 26 15 1Y. ' 27 11 13 ti 114 23 14 121 24 15 125 ' 25 15 14 ti 117 23 L4 124 25 14 12^  ' 25 11 15 ii 118 24. 13 122 24 7 12C 24 14 MEAN V MEAN 133 U N I V E R S I T Y D F B R I T I S H C O L U M B I A LABORATORY OF ANIMAL NUTRITION ' DEPARTMENT OF ANIMAL HUSBANDRY A S S A Y D A T A S H E E T S P E C I E S .WISTAR RAT ASSAYER_ C. M. W.  D A T E /46 th. Day O A T F ii-7th Day n A T F l i S t h Day DI ET  AN IM AL  N UM BE R ID EN TI FI CA TI ON  X Ul V) - i < Z z < L L 0 h I ID ui gms § FE ED  O FF ER ED  CQ z Ul 1-< Ul 0 Ul Ul L L gnu TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  [to  3 WE IG HT  O F AN IM AL  CQ (j|  F EE D OF FE RE D z Ul 1-< L U O L U Ul U. 1 gms TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  §j WE IG HT  O F A NI MA L 2 FE ED  O FF ER ED  CQ z Ul < Ul 0 Ul Ul u. gms TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  U . B . C . Ration # 18. I A male 157 31 14 16( ) 2il 15 L68 25 16 2 ti 17* : 35 13 l ? ) 27 1k L85 29 17 3 n l * j 30 lk 15. 5 23 15 L63 24 13 k . it l M ; 29 17 15 - 23 11 155 23 15 5 n iW > 29 16 1$ ) 2j 16 160 2k 17 MEAN 6 ,n 130 26 1-7 135 20 12 IILC 21 17 7 n 152 30 L8 160 24 15 16 j > 25 16 8 ti "Kli 31 16 157 ?)| lk 16] 2k 16 9 tt 139 28 17 Ikk - 1—7 22 14 Iki 22 18 10 ti 115 23 12 120 18 12 12[ ; 19 13 l l tt 138 28 16 145 22 15 15C 1 23 12 MEAN 12 II llj.0 28 17 145 ^22 12 liic ' 22 13 13 n 129 26 16 136 20 12 IILC ' 21 15 ih' tt 129 26 14 134 20 11 lij.2 21 17 15 tt 129 26 lk 134 20 10 13: . 20 16 MEAN MEAN U N I V E R S I T Y D F B R I T I S H C O L U M B I A LABORATORY OF ANIMAL NUTRITION - DEPARTMENT OF ANIMAL HUSBANDRY A S S A Y D A T A S H E E T sPECiEsyiSTAR RAT ASSAYER C . M„ W , DATE JiQfch Dav n A T F f^Oth Dav DATF «£Lst Dav DI ET  AN IM AL  N UM BE R ID EN TI FI CA TI ON  X Ul (0 3 WE IG HT  O F AN IM AL  | FE ED  O FF ER ED  •a | FE ED  EA TE N TO TA L FE ED  CO NS UM ED  TO TA L W EI GH T GA IN ED  3 WE IG HT  O F AN IM AL  Q Ui 0: .. Ul u. u. 0 Q Ul Ul . U. SJ FE ED  E AT EN  a—  ... . ....  . . .. . TO TA L FE ED  CO NS UM ED  TO TA L W EI GH T GA IN ED  -1 z z < ' u. 0. 1- I 0 Ul 5 tna 3 FE ED  O FF ER ED  Z' , Ul h < Ul 0 Ul Ul u. TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  U . B . C . Ration # 18 I A • 1 nale 171 26 L5 m 26 12 l 8 l | = 27 18 2 II 190 29 L8 197 29 15 20: '•30 18 3 H l6l ?k L6 170 24 14 17< ' 26 17 I. TfiO ?)| Dl 165 23 12 175 26 rl6 11 i t , 163 ^ 25 1 16 170 24 14 17: , 2 6 •13 MEAN 6 i t 145 22 15 148 22 Ik 15* ! 23 15 7 i t 1 7'i ?6 16 170 26 19 18( 1 27 17 1— 8 tt 170 26 16 174 26 14 17' ' 26 16 9 t t 155 23 18 159 23 14 161 . 24 16 10 i t 129 19 l 4 134 20 11 13' ' 20 14 n II 1 ^ 23 12 23 16 16] • 24 13 MEAN 12 t i . 155 23 16 159 23 13 161 . 24 15 13 i t 145 22 15 150 23 12 151 23 16. I I L tt Ikk 22 9 I K 20 15 151 - 23 17 tt 145 22 18 152 23 I5i . 23 23 MEAN - MEAN 115 • U N I V E R S I T Y O F B R I T I S H C O L U M B I A LABORATORY OF ANIMAL NUTRITION DEPARTMENT OF ANIMAL HUSBANDRY A S S A Y D A T A S H E E T SPECIES WTSTAR RAT ASSAYER C. M. W. : DATE 52nd Day I->ATE ^3rd Day D A T E 5i^th Day DI ET  AN IM AL  N UM BE R ID EN TI FI CA TI ON  X HI 0) -i < Z z < LL 0 1-I LU gms 0 Ul K Ul U_ U. 0 0 Ul Ul I L gnu z Ul < Ul • Ul Ul u. gm; TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  's'  W EI GH T O F A NI MA L OCJ FE ED  O FF ER ED  3 z Ul 1-< LU • LU Ul U i gm: TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  3 WE IG HT  O F A NI MA L ^ FE ED  O FF ER ED  CO z Ul 1-< Ul Q Ul Ul u. gms TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  U.B.C Ratior # 18 IA mal< 188 28 15 191 • 29 13 19 ? 30 15 2 n 209 31 17 21a 32 15 >l6 32 1$ .3 n 180 27 17 181 27 15 -90 29 L8 k • n 175 26 23 18C 1 27 12 • 77 26 L0 tt 176 26 16 17c, 26 13 -8$ 28 L6 MEAN 6. 11 157 2k 15 164 2k 15 .6* 25 lk 7 ti 188 28 18 ir. 29 16 -98 30 L8 8 11 180 27 17 18c 27 18 .90 29 1-7 9 ti 169 2? 12 173 2$ 13 •7k 26 L5 10 11 143 22 10 lkc, 22 12 •$l 23 1-3 11 ti 165 2$ lk l6i 2$ 15 .69 25 L9 MEAN 12 11 167 2$ 1$ 17s 26 16 .80 27 i-7 13 ti 160 2k 13 16s 2/4 15 .68 25 L5 ik 11 1^8 2k 15 162 2k 15 .68 25 L8 1$ 11 157 2k 19 166 2k 15 -70 25 L6 MEAN MEAN 116 U N I V E R S I T Y O F B R I T I S H C O L U M B I A LABORATORY OF ANIMAL NUTRITION DEPARTMENT OF ANIMAL HUSBANDRY A S S A Y D A T A S H E E T S P F r . i F S Ml STAR RAT' L" ASSAYER C. M. W. _ DATE 55th Day n . T F 55th Day H A T F 57th Day DI ET  AN IM AL  N UM BE R ID EN TI FI CA TI ON  X Ul in j 4 Z 4 L L 0 1- . I 13 ui 5 gms jl FE ED  O FF ER ED  ta  z Ul h- 4 Ul D Ul Ul L L gm; TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  on  CO WE IG HT  O F A NI MA L Q Ul X Ul L L L L 0 Q Ul Ul L L gms • z Ul i - 4 Ul 0 Ul Ul Ii. gms TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  3 WE IG HT  O F A NI MA L CO Q Ul X Ul U. L L 0 O Ul Ul u. gms z Ul h 4 Ul 0 Ul Ul L L gms TO TA L FE ED  CO NS UM ED  TO TA L WE IG HT  GA IN ED  U.B.C. Rati or # 18 IA n lale 201 30 16 20^ 31 18 209 31 13 2 I I 221 33 L4 225 34 17 229 34 14 3 t! 193 29 L3 200 30 — , 187 28 19 4 ft 184 28 Ik I89 28 16 192 29 15 5 ft 192 29 L5 1 L99 30 18 20j 30 14 MEAN 6 tt 169 25 L4 185 26 16 12l| . 26 T5 7 tt 206 31 L6 210 33 19 21S : 22 18 8 tt 200 30 L5 209 33 16 21C 32 16 9 I I 176 26 L4 L87 28 - 192 29 9 10 tt 158 24 13 160 24 15 165 ; 25 15 11 tt 179 27 11 179 27 20 18c ' 28 13 MEAN 12 tt 184 28 18 I89 28 17 18S ' 28 17 13 tt 171 26 1.5 178 27 16 17S 1 27 15 14 tl 174 26 L5 180 27 18 182 ! 27 15 15 tt 177 26 16 185 28 16 181 ' 28 17 MEAN MEAN U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S WISTER RAT A S S A Y E R • C. M. W. D A T E 58 th Day H A T E 59th Day H A T F 60th Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X LU CO 3  W E IG H T  O F  A N IM A L  §  F E E D  O F F E R E D  ca Q F E E D  E A T E N  3 m T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  P  W E IG H T  O F  A N IM A L  g  F E E D  O F F E R E D  z Ul < Ul 0 Ul Ul u. OTIS T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  §  W E IG H T  O F  A N IM A L ' |j  F E E D  O F F E R E D  Z UJ 1-< Ul 0 Ul Ul u. 1 gm; T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Ration # 18 IA **• m 213 32 111 220 33 ' 3^ 18 2 » 234 35 * T 16 242 36 18 2i|l 1  - 36 15 3 • it 2 0i|. 30 14 207 31 17 21( > 31 16 4 II 199 30 16 20lj 31 18 20C > 31 17 5 II 206 30 17 2li| 32 17 21' ' 32 18 M E A N .- 6 tt 180 27 14 I85 28 17 1 l8< 1 28 17 7 tt 219 33 18 225 34 20 23C • 35 20 8 II 216 33 15 220 33 21 22l . 33 19 9 tt 190 28 11 191 29 13 195 ! 29 19 10 it 170 26 15 175 26 18 171 ' 26 17 i i it 191 28 18 196 29 17 19* 29 18 M E A N 12 n 196 29 17 201 30 17 20; ; 30 16 13 ti 184 27 17 I89 28 16 195 29 19 it 185 28 17 195 29 17 19' ' 29 18 10 it 193 28 16 197 29 18 19 c 29 18 M E A N M E A N 116 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S WISTER RAT A S S A Y E R C. M. W. D A T E 61 st Day" D A T E 52nd Day D A T E , 6 3 r d Day Ul U.B.C,. Ration # 18 Ul m 2 3' Z - I < z < IA z g < I -z Ul Q X Ul mal M E A N 8 10 11 12 15 M E A N J < Z < LL 0 ' h- X Ul gms 228  2J48  220 215 220 190 235 229 192 185 200 209 193 201 205 M E A N a Ul X Ul U. LL 0 Q Ul Ul LL gms A 37 _33 33 33 29 35 28. 30 31 29 30 31 z Ul I- < Ul Q Ul Ul U. gm  16~ 15  17 15 16 IL 24 12 16 18_ 16 Q Q Ul ui 28 Ul I 13 uj • ft 0 1- < z < LL 0 h I U Ul 5 gnu gmi3 gm; 195: 29 Q Ul IE UJ LL LL 0 Q Ul Ul LL 18/ 28 z ui 1- • < Ul Q Ul Ul LL !5_ 16 Q Q UI QJ Ul s °8 I- I 13 0 h- < Z < LL 0 I - X ui 5 gmi3 gm3 gm 1 197 30 Q Ul DC Ul LL LL 0 Q Ul UJ LL 190 29 z UJ I- < Ul Q Ul Ul u. 17_ 13_ Q Q ui ui UJ 5 28 I- I 13 LU F> M E A N 119 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wigtap Pat, • A S S A Y E R C M . ¥ .  D A T E 22nd Dav H A T F 23rd Day - D A T E 24th Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  ^  W E IG H T  O F  A N IM A L  Q Ul tt Ul u. u. 0 Q Ul Ul U. z Ul 1- < Ul • Ul Ul I L ecms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3  W E IG H T  O F  A N IM A L  • Ul tt Ul u. u. 0 Q Ul Ul U. OTIS z Ul 1- < Ul o Ul Ul u. . OTIS T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  §  W E IG H T  O F  A N IM A L  S  F E E D  O F F E R E D  g  F E E D  E A T E N  ca  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C." Ration #18 IB nale 50 5 0 47 10 3 4S 10 6 2 I I 48 5 0 43 10 4 46 10 •8 3 it 45 5 2 42 10 5 4i • 10 8 4 I I 45 5 2 41 10 4 4; . 10 8 . 5 ti 40 5 0 42 10 0 3* i 10 M E A N 6 I I 34 5 1 35 10 5 4C 10 10 7 I I 37 5 1 30 10 4 36 10" 7 8 I I 36 5 2 34 10 5 35 10 '8 9 I I 36 5 0 34 10 3 '35 10" 9 10 I I ^6 5 4'" 34 10 46 10 8 IT ti ^6 , 0 33 10 6 41 10 9 M E A N 12 : it 35 5 3 35 10 4 36 10 8 ' 13 I I 34 5 5 35 10 6 34 10 "9 14 it 33 5 3 34 10 6 3^ 10 8 • 15 ii 33 5 5 34 10 5 3 C 10 6 M E A N M E A N 120 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T <;pFr.iFs Wistar Rat A S S A Y E R C. M. W. D A T E 25 th Day n A T F 26th Day ' D A T F 27 th Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul (/) - i < Z < LL 0 1- I (3 Ul 3  F E E D  O F F E R E D  z Ul < Ul Q Ul Ul u. gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  n | W E IG H T  O F  A N IM A L  D Ul X Ul U. U. 0 0 * Ul Ul LL OTIS • z Ul . < Ul a . Ul Ul . u gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  B  W E IG H T  O F  A N IM A L  CO  Zj  F E E D  O F F E R E D  z -Ul K < . Ul o. Ul Ul LL gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Ration #18 IB male 49 6 6 52 7 7 55 6 6 2 H 50 6 6 50 7 ; 7 55 7 7 3 49 5 5 48 6~; 6 50 6 6 4 » 48 5 5 48 6" .6 50 6 6 . 5 I I 41 5 5 43 5 5 44 6 6 • M E A N 6 45 4 4 40 4 4 39 5 5 7 " 40 6 6 44 6 6 45 6 6 8 38 6 6 40 6 6 43 6 6 9 ti- 40 6 6 41 6 6 44 7 7 10 'i 50 6 6 52 6 6 53 6 6 n tt 45 6 6 44 4 4 41 7 7 M E A N • 12 40 6 6 40 6 6 43 6 6 ' 13 » 42 6 6 42 6 6 44 6 6 14 40 6 6 40 6 6 42 6 6 15 39 5 5 40 5 ; 5 42 6 6 . M E A N . . . M E A N i 2 i U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wistar Rat A S S A Y E R f!. -M. W.  D A T E ?8t.h nav R A T E ! PQth Dav D A T E ^Oth Dav D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul 0) - I < z < u. 0 1- I (3 Ul 5 ems a m X in u. u. 0 0 Ul Ul u. ems z Ul 1-< Ul o Ul Ul u. ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  - i < z < u. 0 I - X C5 Ul . ems Q . Ul X r': ui u. '.It . y j t s ^ U.;" :. em? z •UJ :-. K . :••<•• ". :w 5"o .. <?UI >':ui ' u ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  g  W E IG H T  O F  A N IM A L  rq  F E E D  O F F E R E D  g z -Ul 1-< . Ul 0 Ul Ul u. ; em: T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U . B . C . 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O < z < LL 0 H I 0 Ul 5 Rtns, g  F E E D  O F F E R E D  z Ul I -< Ul • Ul Ul LL T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3 W E IG H T  O F  A N IM A L  Q Ul a: Ul LL LL 0 Q Ul Ul U. z Ul 1-< Ul Q Ul Ul Li. em? T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  < z z < u. 0 h X 0 ui em; K) F E E D  O F F E R E D  z LU 1-< Ul 0 Ul Ul LL 3 em, T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. R a t i o n #18 IB ma 1 ( 70 8 8 73 8' 8 75 9 9 ? 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Ul ems UJ F E E D  O F F E R E D  3  R A  F E E D  E A T E N  3  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  m 3 W E IG H T  O F  A N IM A L  ro  g  F E E D  O F F E R E D  CO  Z - Ul < Ul Q Ul Ul LL ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. R a t i o n #18 IT mal ! 81 9 9 85 9 8 89 8 8 ? 81 10 10 85 10 10 90 9 9' 3 u 73 4 4 73 4 4 75 7 7 4 • I I 81 1? 1? 86 11 11 93 10 10 I I 64 7 7 65 7 '7 70 1? 1? M E A N 6 M 6C 8 8 63 7 7 66 8 8 7 M 66 8 8 69 8 8 74 8 8 8 „ 6f ' 8 8 6? 8 8 66 8 8 9 ,1 67 9 9 68 10 74 14 14 10 ,1 7<T 5 69 6 73 6 6 11 I I 6C 7 7 63 8 4 65 8 1 M E A N 1? „ 6* 9 9 67 9 9 73 8 8 ' 13 „ .•6C 7 7 63 6 6 66 5 ' ~j— 14 „ 6? 8 8 65 8 8 70 1? 1? 1 5 6 C 8 8 67 10 10 74 6 6 s— M E A N M E A N •' i 2 4 U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P F C . F C ; WISTAR RAT A S S A Y E R C. M. W. D A T E 37th Day H A T E 38 th Day H A T F 39th Day D IE T A N IM A L N U M B E R  ID E N T IF IC A T IO N  X HI V ) _ i < Z < UL 0 H I 1 5 Ul z;ras Q Ul tt Ul u. U: 0 " Q Ul Ul U. gms z Ul 1- < Ul • Ul Ul u. ' gms T O T A L F E E D  C O N SU M E D  T O T A L W E IG H T G A IN E D  H  W E IG H T O F A N IM A L 0. Ul LT Ul U. L L 0.' 0 - Ul Ul U. gm, z Ul 1- < Ul Ul Ul .-• u. 3gm; Qo Ul Ul Ul 5 1- , I. 1 3 u Q 5z < < 3 0 1- -1 < z < u. 0 1- I 1 3 Ul sma OKI 3 F E E D  O F F E R E D  CO  z - Ul 1- < UJ -0 Ul Ul u. gms T O T A L F E E D  C O N S U M E D  T O T A L W E IG H T G A IN E D  U.B.C Ration #18 I B ] dale 93 10 98 10 10] 10 "10 2 ft 10 95 10 10)| n n 3 II 81 10 88 8 92 9 9 n 95 13 104 18 11] 12 10 5 ti 80 12 85 11 91 13 13 M E A N 6 i i 70 7 70 7. rt 9 9 7 n 78 8 80 8 8k . 9 9 8 II 70 13 79 13' 86 14 14 9 it 83 14 88 13 12 96 15 14 10 II 78 6 77 6 8] 7 7 i i it 66 8 69 9 0- 7= 8 8 M E A N 12 ti 75 8 75 8 8] 9 9 13 it 67 6 IT 69 6 7] 6 6 l 4 it 74 10 85 12 8c 13 13 15 ti 75 6 75 6 77 7 7 M E A N • - M E A N . 12$ U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P F C I F S VISTAR RAT A S S A Y E R C. M. W. D A T E kQth Day D A T E 4 l s t D a y D A T E 42nd Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X HI If) -i < Z < I L 0 1- X 111 gms • in or Ul LL LL 0 Q Ul Ul LL gms z Ul 1-< Ul Q Ul Ul LL gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  m gj W E IG H T  O F  A N IM A L  • Ul LL Ul LL LL 0 Q Ul Ul LL gms z Ul h < Ul Q Ul Ul U gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  -1 < z < LL 0 H I O Ul 55ms £j F E E D  O F F E R E D  ro z LU 1-. < . Ul • Ul LU LL gm£ T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. R a t i o n " 18 IB I iale 10i) . 8 1 0l| R 10^ 10 2 n 10C > 9 .10 9 115 8 3 i t 9( » 9 LOO 8 106 8 )\ tt ll't ' l'l 11 119 11 9 128 13 •7 • — M f * — 5 tt 9 C ; 12 L01 12 110 12 M E A N 6 it 78 8 85 8 90 11 7 tt 88 9 L91 8 95 8 8 tt 93 13 : Ll LOO i4 12 108 12 10 9 tt 98 15 8 L02 16 11 109 1: 7 10 tt 83 7 89 6 91 6 11 tt 72 9 5 75 8 4 82 8 4 M E A N 12 tt 82 9 87 9 90 8 13 tt 70 6 75 7 76 7 l4 tt 95 14 : L2 L02 14 11 109 12 10 15 i t 78 8 86 9 90 8 M E A N M E A N 126 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T Q P F n i W Q yI STAR RAT -v»V A S S A Y E R C f M« W. • - D A T E Jj^rdDay n A T F l+ll-th Day r i A T F 45th' Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X LU in g  W E IG H T  O F  A N IM A L  to Q LU X LU LL LL 0 Q Ul Ul U. gms z Ul 1-< Ul o Ul Ul li. gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  j < Z < LL 0 1- I LU 5ms 0 Ul Lt Ul u. u. 0 Q Ul Ul u. ,-' gms •; z Ul 1-< Ul 0 Ul Ul u gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  < z < U. 0 1- I 0 Ul gms 0 LU X Ul LL LL 0 0 UJ Ul gms Z - Ul 1- < . Ul Q Ul Ul LL grru T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration # 18 IB 3 aale 113 125 14 12< 1 12 2 it 117 12 12: 13 12 12< » 16 11 3 II 106 9 11] 14 11< > 14 il n 132 13 8 13< 13 8 13: 8 II l l l ' r 11 111 • 16 12( E> 8 M E A N 6 ti 9k 8 9^  ; 8 9' ? 9 7 n 97 9 105 t 10 10 3 10 8 II 111, 13 nf \ 14 • 12 ? 15 9 II 11' l l i ill I 14 12, t- 15 12 T n ii 9»l $ 9( » 6 9 7 .9 11 ti / t 85 : 8 8' f 9 9 D 10 9 M E A N 12 II 1 9 9: > 8 9 5 si 13 ti K • 7 71 \ 6 8 0 $ 14 ti n : \ 12 11 1 14 12 5 1^  1? II 9C i 8 9: l 8 9 5 9 M E A N M E A N 127 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T . p p n F , WISTAR RAT A S S A Y E R C - M - W * , • D A T E }|6th Day D A T E i |7 f c h D a y D A T F hfith. Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul V) P  W E IG H T  O F  A N IM A L  CO  fc j F E E D  O F F E R E D  CO z Ul H < Ul • Ul Ul l l . gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  J < Z < Ii. 0 1- I 0 Ul 5£?J1S ^ F E E D  O F F E R E D  ' z Ul 1-< Ul 0 Ul Ul u gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  < Z ' < u. 0 I Ul ma 11 F E E D  O F F E R E D  CO  z . Ul 1-< • Ul • Ul Ul u. gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration •#. 18 IB naif 1 33 1)|0 1 2 l ) | c 2 it 134 1 16 lij.0 15 •••• | 145 r 14 3 it 126 16 L33 15 14C 13 4 . n liiO 12 L0 Li|.2 12 12 i4i 11 5 tt 125 11 L30 15 13£ 14 M E A N 6 tt lOli 8 105 8 11c 12 7 tt 110 8 111 8 111, 11 8 tt 132 15 137 16 14; 14 9 tt 128 15 133 10 13I1 10 10 tt 104 1# LOix. 7 IO-J 8 i i tt 95 10 100 10: .'- 10c 10 M E A N 12/ tt 98 9 101 10 101 ' &2 13 tt 80 5 80 5 83 5 tt 127 11 128 14 135 11 15 tt 99 10 L01 10 101 9 M E A N M E A N 128 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S . WISTAR RAT A S S A Y E R C. M. W. h bl U.B.C. Ration #18 111 m o z _ l < z < _1B X z 0 F < u LL F z UJ Q X Ul in malii M E A N 8 10 11 M E A N 12 13 2k- 15 M E A N D A T E . Day. - I < z < LL 0 I -x 13 UJ 15Q 1^ 7 145 ikS. ll±2 115 112 145 134 :[o8 106 i n  82 135 l i o 11+ Q Ul X UJ u . LL 0 Q UJ Ul U. JL2_ 13_ l k 11 2k l k 10 i k UL 8 8 11 z Ul h < Ul Q Ul Ul u. -gmi Q Q Ul LU Ul 5 So K X o 0 I- n A T F 50th Day . - i < • z < LL 0 h X (3 Ul 5 gma_gm^ gms 15,3 12 142 148-14 153 2k2 12C 14c 11c _5J a UJ LT Ul U. LL 0 Q Ul Ul u. 13 1 1 is. 12 -11 10 113 9_ 84 6 116 13 z Ul I- < Ul O Ul Ul u. 12 Q Q U I ui Ul 5 28 X CD *z -is 13 4 Z < LL 0 h- X o iii fims D A T E gist Day Q LU o: U I u. u . 0 Q Ul Ul u. 160 15 155 15 i5:ui> 129 17  122 9_ 15<> 14 148 18 i l l , 8 115 9 8t 7 i k L i i 124 7 z Ul < Ul Q Ul Ul u. gma 13_ 8 Q Q U I ui UJ 5 M E A N ; 129 U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S WISTAR RAT A S S A Y E R C-M. ¥ , — : — D A T E ^Pnri Tiny H A T E ^ t r d Day D A T E ^lith Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul in 3 W E IG H T  O F  A N IM A L  a g F E E D  O F F E R E D  a z Ul l- < Ul • Ul Ul u. T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  a 0 W E IG H T  O F  A N IM A L  3 F E E D  O F F E R E D  a z Ul 1- < Ul Q Ul Ul u. T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  -1 g W E IG H T  O F  A N IM A L  3 F E E D  O F F E R E D  a z Ul 1- < Ul 0 Ul Ul u. pjns T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U . B . C Ration # 18 IB malt 165 16 "•5 111 1 76 1 ? 2 t i L60 16 J .2 -65 16 11 168 llf 6 3 n 159 16 65 16 15 166 1 1 13 }\ II l6/| 12 L67 12 172 16 14 —*r*— 5 it r • L60 17 L65 16 172 13 TgT- r — 2 M E A N - 6 ti 135 1? 9 38 17 9 1J|0 1 7 7 II i?5 10 27 TO 1 130 Q 8 II L58 1M- ,61 16 170 7— 16 9 II L53 18 L6O li|. 160 111 10 II Ll5 8 L17 8 121 8 11 n 98 10 8 ,07 8 105 6 M E A N • 12 II L19 10 L23 11 128 11 13 II 90 7 89 7 95 7 iij. II i-47 9 L!L8 9 149 15 15 ti L20 14 L27 Ik 133 16 M E A N M E A N 130 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T gpFr.iFgWTSTAR RAT A S S A Y E R C. M. W.  D A T E 5 £ T H Day D A T E ^6th T^ay D A T E Xjth f)ay D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X 111 to 'jj l W E IG H T  O F  A N IM A L  CO  a in X Ul u. LL 0 0 Ul Ul U. gmj z Ul 1- < Ul Q Ul Ul LL I gm: T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  • J < z < u. 0 i - I 0 ijj ;ms a Ul X Ul u. LL 0 • Ul Ul LL gms z Ul 1- < Ui Q Ul Ul LL gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  _l < z < L L 0 h X g Ul nua 0 Ul X Ul LL LL 0 D Ui Ul LL gms z Ul 1- < Ui Q Ul Ul I L gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Ration # 18 IB 11 Lal_a 180 1 ? 1 0 18o 1 2 18 15 2 n L70 14 : 10 L73 13 Ilk 13 3 # L73 14 : -3 L76 17 15 182 17 13 4 tt L78 12 : Ll -79 12 9 179 10 7 5 ' tt L75 16 L80 13 180 13 M E A N 6 it L44 15 : L0 L47 14 13 148 14 13 7 tt L35 9 L36 10 135 13 8 tt L75 i l f .80 17 182 17 9 tt L65 16 L70 13 169 12 10 tt L20 8 .22 8 120 8 11 n L09 9 .11 9 107 8 M E A N 12 tt L31 11 •36 8 132 14 13 tt 96 8 .00 8 98 8 14 tt L55 17 .61 15 163 15 15 tt 18 -51 20 17 156 19 15 M E A N M E A N 131 U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y . A S S A Y D A T A S H E E T SPECIESJflLLSTAB—BAIT A S S A Y E R C. -M» w : _ D A T E 5 S T H"Day R A T E 5Qth Day D A T E 60th Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul V) §  W E IG H T  O F  A N IM A L  CQ  a Ul K Ul U. LL 0 a Ul Ul LL KD13 z Ul l - < Ul a Ul Ul LL gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  gj W E IG H T  O F  A N IM A L  H  F E E D  O F F E R E D  ca z Ul 1- < Ui 0 Ui Ul LL gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  %  W E IG H T  O F  A N IM A L  to F E E D  O F F E R E D  z LU 1- < Ul 0 Ul Ul LL 1 gms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration # 18 1R naif i fig "15 19C ) 15 191? 13 ? II 180 » L83 17 13 186 18 3 II 186 1 15 L91 18 17 197 13 )| ti l 79 10 L82 \% 13 185 14 12 1 5 II 181). 16 L92 15 193 M E A N 6 n 156 15 L64 14 165 14 7 n 1)|3 15 150 16 l t f 15 8 ti 190 17 - 195 18 19' ' 15 9 ti 174 15 177 14 17i ' 14 10 it 125 9 130 14 135 ; 11 l l ti 112 9 115 8; 112 ! 9 M E A N 12 it 139 17 1* 1 11 13 it 101 8 105 6 10' ; 6 111 tt 1,68 18 176 15 17* i 18 1 15 tt - 4 172 16 17c 1 16 M E A N M E A N U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wis t a r Rat A S S A Y E R C.M.W.  D A T E 6 l s t Dav D A T E 62nd Dav D A T E 63rd Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X LU CO -1 < z < LL 0 1- • X o 111 £ms ^ F E E D  O F F E R E D  Ji z bl 1-< LU Q Ul LU li. TO T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3  W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  3 z LU 1-< LU O LU Iii li ; em< T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  <. z < LL 0 h I O LU gm: jq F E E D  O F F E R E D  3 z LU 1-< LU Q LU LU LL  em w T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  . . U.B.C. Rati o n #18 1"R ma 1 < POO ? 1,80 14 19 q 18 13 19 > 15 11 3 „ 198 13 4 M 189 11 15 194 15 12 19 > 15 13 .1 POO If M E A N 6 „ 167 14 \% 15 14 -74 16 12 7 .1 160 If 16c • 16 L71 16 8 „ POO 1 c 20; 9 „ iRO IB? 14 185 1 5 13 10 „ i^6 14 14^ • 11 L46 11 11 11 113 c I T ; ' 18 L19 9 M E A N 1? I I 14C V 15( > 13 155 16 14 -13 I I 104 ( 10' ' 6 L06 6 14 I I ' 183 y, 18< » 17 L91 • 17 1 5 „ 17? K 17c > 16 15 L81 16 15 M E A N M E A N '133- .. U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wis tar Rqt. A S S A Y E R r i j j ^ f ,  D A T E 6 4 t h Day D A T E -6^t.h Day D A T E 6 6 t h r>a v D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  /  , X III W) 3  W E IG H T  O F  A N IM A L  3  F E E D  O F F E R E D  Z " 111 t- < 111 0 111, Ul LL .gtn-s T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  -i < z < u. 0 H X e> ui ^ F E E D  O F F E R E D  li * Z Ul 1- < Ul . 0 Ul Ul u p-inc; T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3 W E IG H T  O F  A N IM A L  Q F E E D  O F F E R E D  n q F E E D  E A T E N  3 T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U . B . C , R a t i o n #18 B Tiale - 2 .. 197 197 1 5 3 ' .. . •4 ' I I 198 16 14- >0? - M E A N 5 ; „ 179 14 18? 14 186 1 4 1 3 6 ' I I 175 18 183 1 7 18 1 7 7 „ 1 J 8 „ L89 12 11 186 "12 18c 1? 9 149 1.2 13 1.^ 6 13 10 „ 1 23 10 1 ?7 l n -pr - L_' 1 A M E A N ~ K-l> 11 l 6 l ' 13 163 1 5 166 1 5 1? „ 107 7 L09 11 115 10 13 198 1 8 5 0 4 14 „ _1$? L8Q 17 * T6 194 16 M E A N . M E A N 134 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wistar Rat • A S S A Y E R n.M.W.  D A T E 6 7 t h Day r>ATE 6 8 t h Bav D A T E 6 9 t h Dav D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X Ul U) g W E IG H T  O F  A N IM A L  3  F E E D  O F F E R E D  Q F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  g W E IG H T  O F  A N IM A L  q F E E D  O F F E R E D  3 ' '' : z Ul 1-. < Ul ' Ul Ul U. ^ Crm: T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  < i < u. 0 h I 0 Ul rm.s g F E E D  O F F E R E D  Z Ul h < Ul a Ul Ul u. cms T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Rat i o n #18 ' . M E A N - 6T ma 1 1 7 1 4 19' 1 8 7 1 4 7 it I f , 16 ?0( ) 9 it 18? IS 1 19^ ! 19 L86 12 1 0 II 161 '1 \ 16< > 1 5 165 1 5 1-1 ' i i 1 3 f I f 1 13 1 4 1 f 1 5 1 4 0 16 M E A N 12' u 171 If 17* ) 17 L74 17 13 ti i ? r 11 l?f > 1 0 1 2 0 11 1 5' I I I Q f 1? \ 15 P O M E A N M E A N 135 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wistar Rat A S S A Y E R C.M.W.  D A T E 70th Day n A T F 71st Dav D A T E 72nd Dav D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  g W E IG H T  O F  A N IM A L  | F E E D  O F F E R E D  0 q F E E D  E A T E N  A T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3  W E IG H T  O F  A N IM A L  • Ul OC-Ul LL LL 0 Q Ul Ul LL Pi IT Ul 1- < Ul • Ul LU LL 3 p;tP! T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  | W E IG H T  O F  A N IM A L  q  F E E D  O F F E R E D  z Ul 1- < , Ul • Ul Ul u. s..:.prri « T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Ration #18 M E A N 1 • 1 8 8 14 191 • l 1 ^ Q 5 0 0 9 11 19C 1 1 1 9 c ) 1 1 1 9 1 1 1 1 0 it 17C 1 \ ' 1 3 17,1 ' 15 18 1 ?o 1 5 1 1 11 15? 1 ? 1 0 16(1 )' 1'3- in 1 6 < ) 13 M E A N 12' 11 183 H • 12 18 J : 16 14 19' > 17 13 11 127 K 13: 14 \ 15 M E A N M E A N 136 U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T SPECIES Wis t a r Rat ASSAYER C.TW.W.  D A T E 73rd Dav nATF 74th T)av D A T E 75th Pay D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  q g W E IG H T  O F  A N IM A L  Ii | F E E D  O F F E R E D  z ui < 111 Q Ul Ul u. PTT1< T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  g  W E IG H T  O F  A N IM A L  q  F E E D  O F F E R E D  z Ul . 1-< Ul • UI Ul u f tr : T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  9 W E IG H T  O F  A N IM A L  0 F E E D  O F F E R E D  Z LU h < . Ul 0 Ul Ul LL g gm a T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Rati o n # 1 8 M E A N E ma l i 9 ti 194 1 9 1 8 ?0- 10 I I 183 1 1 1 8 ? 1 6 11 1 8 ' 7 1 6 11 11 I I 1 ^ 9 1 < 16- 14 11 16* ^  1 ^ 1? M E A N 1? it 193 1/ 13 19f ' 17 16 1 9 ' 1- 17 7 1 3 it 147 — i l , c 1? • 1? Q 1.5' 1 1—r- L 1 6 r_ • M E A N M E A N 137 : U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wi .q ta r IRa t • ' / • A S S A Y E R H.TW.W.  D A T E 7 6 t h Dau D A T E " 77th T)q V H A T F 7 8 t h ' Ha v D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  rq •• 3  W E IG H T  O F  A N IM A L  Ji g F E E D  O F F E R E D  Ji z ui h < 111 Q lil Ul li. T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3  W E IG H T  O F  A N IM A L  n o- Ui •a Ul " u. • ll." , 0 o " Ul Ul u. . •- z • • •ui , < ...111 .'o Ul Ul u. : cm? T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  | W E IG H T  O F  A N IM A L  tj  F E E D  O F F E R E D  Z - Ul 1- < . Ul 0 Ul Ul IL T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U . B . C . R a t i o n #18 . 1 M E A N •' "R ma 11 10 II 189 13 12 192 14 13 T 9 [ ; 1 5 8 TT ti 173 19 1 ? 1 74 1 1 7 ' : 19 8 ' M E A N I P I I 195 1 7 14 199 1 7 15 13 n 157 13 1 6 f 1 3 16' » 1^ IP ' in j ( M E A N - - • - . . M E A N ' 138, U N I V E R S I T Y D F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P F C I F S Wistar Rat . y.^-.k- A S S A Y E R C.M.W.  D A T E 7 9 t h Dav D A T F ' ' \ -'v80th Dav D A T E • 8 l s t Dav 1- UJ Q A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  - i < z < LL 0 h I O Ul s F m s | F E E D  O F F E R E D  z lli h < lli • 111 111 U. cm.c T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3  W E IG H T  O F  A N IM A L  0 in :.. X Ul LL ' u.: 0' J ... Ui' Ul LL CT mc -• z . Ul 1- < Ul ':,a Ul LL T O T A L  F E E D . C O N S U M E D  T O T A L  W E IG H T  G A IN E D  J 4 z < u. 0 1- I 0 ui 5 c m ' Q F E E D  O F F E R E D  3 F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C. Ration #18 M E A N R ma I? 1 0 11 1 9 6 16 13 1 9 8 1 6 pnz 11 11 1 7 6 1 9 11 1 7 9 18C ) P 0 1 ? M E A N ' n 1 6 9 1 5 1 73 ; I P 1 7 C r 1 6 1 P M E A N M E A N 139 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S W i s t a r R a t r _ - A S S A Y E R Q nM.W,,  D A T E R P n r l fla v D A T E / . • 83 r r ! D a v R A T E 84th Dav D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  it) g W E IG H T  O F  A N IM A L  3  F E E D  O F F E R E D  3 It) F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  - i < z < LL 0 h I 0 Ul BP'S Q Ul Lt Ul LL LL 0 0-< . . U l " • Ul ; u. '•" err. z • UI 1-< . 0 : ui • Ul tL 3 eni: T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  3 W E IG H T  O F  A N IM A L  Q Ul a. Ul u. LL 0 0 Ul Ul LL ems z - Ul 1-< . Ul Q Ul Ul LL ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U . B . C . Ration #18 - - - M E A N j j 11 i t 182 2< ) 9 17 c ) 20 11 L82 20 10 M E A N • . >. 3.3 II 17£ If . 14 18< .17 • 13 18 ? 17 13 M E A N • • M E A N 140 U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P E C I E S Wi s t a r Rat, ', ' , V A S S A Y E R O.M.W.  D A T E R^th TlflU D A T E ' 86th Dav D A T E 87th Da v " D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X in J < £ < Lu 0 h X o Ul 5 ?ms it) g F E E D  O F F E R E D  ~Ji • z Ul 1- < Ul • Ul Ul I L em? T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  j < t z < u. 0 r- X 0 Ul 5 ?mf? Q Ul o: » Ul I L I L 0 Q . Ul' Ul LL ems z Ul 1- < Ul a Ul Ul Li. ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  < z < UL 0 I - I 0 Ul ems o Ul Lt Ul LL LL 0 Q LU Ul LL emf z • Ul 1- < Ul Q Ul Ul LL I ems T O T A L 'F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration. #18 • U - 4 M E A N • B na 1 F U ti 186 13 10 185 -l-3f 11: 18^ 20 11 M E A N 13 I I 1RR •16 13 189 16 -15 19" 16 1?' M E A N M E A N 141 (a) U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P F P . I F S Wis tar Rat -fr: A S S A Y E R C.M»W«  D A T E 88th Day H A T E 89th Dav D A T E 90th Day D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X cn B  W E IG H T  O F  A N IM A L  g  F E E D  O F F E R E D  z Ul 1- < Ul 0 Ul Ui u. ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  B  W E IG H T  O F  A N IM A L  0 u a: Ul U. u. 0 Q Ul Ul U . fi ems •; z Ul 1- < Ul 0 Ul Ul Js. u. ems T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  g  W E IG H T  O F  A N IM A L  m  F E E D  O F F E R E D  z • Ul 1- < Ul 0 Ul Ul u. T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration #18 M E A N 11 189 20 7 190 20; ..MO 19S : 20 10 M E A N 13 194 20 8 196 20 10 19* i 20 14 M E A N M E A N 141 (b). U N I V E R S I T Y O F B R I T I S H C O L U M B I A ( ^ L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P F P . I F S W1.qf.ar Rat, A S S A Y E R C.M.W. . D A I I - E o/ist Day D A T F QPnri Day D A T E Q3rrl Day S *J ' w 1 " ' J D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  X hi U) W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  F E E D  E A T E N  T O T A L  F E E D  . C O N S U M E D  T O T A L  W E IG H T  G A IN E D  W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  U.B.C Ration #18 M E A N < i 11 1% ! 20 10 L9<? 20 10 19? 20 10 M E A N i 13 20( ) 20 M E A N i M E A N 141 (c) U N I V E R S I T Y O F B R I T I S H C O L U M B I A L A B O R A T O R Y O F A N I M A L N U T R I T I O N D E P A R T M E N T O F A N I M A L H U S B A N D R Y A S S A Y D A T A S H E E T S P F f . l F S Wjqf-ar Rat A S S A Y E R C.MoW* D A I I - E 94th Dav D A T E D A T E . D IE T  A N IM A L  N U M B E R  ID E N T IF IC A T IO N  S E X  W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  W E IG H T  O F  A N IM A L  F E E D  O F F E R E D  F E E D  E A T E N  T O T A L  F E E D  C O N S U M E D  T O T A L  W E IG H T  G A IN E D  TT B C Ration #18 M E A N 11 200 20 M E A N i i / M E A N M E A N V - BIBLIOGRAPHY - A. L i s t of References a 141 LIST OF REFERENCES Anderson, W.E. and Smith, A.H., "Observations of Rapid Growth in the Albino Rat," American Journal of Physiology. 100:511, 1932. Andrews, F.N. and Bullard, J.F., "The Effect of Partial Thyroidectomy on the Fattening of Steers," Proceedings of the American Society of Animal Pro duction. 1940, p. 112. 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