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Modelling for the estimation of the metabolic energy requirement of laying chickens Dornan, Robert John 1984

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MODELLING FOR THE ESTIMATION OF THE METABOLIC ENERGY REQUIREMENT OF LAYING CHICKENS / BY ROBERT JOHN DORNAN A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN THE DEPARTMENT OF POULTRY SCIENCE THE UNDERSIGNED CERTIFY THAT THEY HAVE READ AND ACCEPT THIS THESIS AS CONFORMING TO THE REQUIRED STANDARD THE UNIVERSITY OF BRITISH COLUMBIA VANCOUVER, BRITISH COLUMBIA FALL, 1984 © Robert John Dornan, 1984 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of P ou l t r y Sc ience  The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date October 12, 1984 DE-6 (3/81) A B S T R A C T ; : E x p e r i m e n t s were conducted t o a s s e s s t h e degree of a c c u r a c y w i t h which t h e Metabol i z a b l e Energy (M.E.) r e q u i r e m e n t s o-f l a y i n g c h i c k e n s i n p r o d u c t i o n c o u l d be p r e d i c t e d . Three of t h e most r e c e n t l y p u b l i s h e d p r e d i c t i o n models (Emmans 1974, McDonald 1978, and NRC 1981) were e v a l u a t e d u s i n g p r o d u c t i o n d a t a c o v e r i n g a f u l l l a y i n g c y c l e . W h i l e each model proved v a l i d under c e r t a i n e n v i r o n m e n t a l , p h y s i o l o g i c a l and p r o d u c t i v e c o n d i t i o n s , none was v a l i d over t h e f u l l p r o d u c t i o n p e r i od. A new e q u a t i o n was deve l o p e d as a d e r i v a t i o n of t h e NRC (1981) e q u a t i on. 0.75 (25-T) (E-62) ME = 128 W * 1.015 + 5.50 6 + (2.07 * 1.03 ) * (E*R) WHERE:. ME = METABOL IZABLE ENERGY, KCAL/DAY W = BODY WEIGHT, KG G = BODY WEIGHT GAIN/LOSS /DAY, GM E = EGG WEIGHT, GM R = 7. RATE OF LAY / 100 T = AMBIENT TEMPERATURE, ° C A f a c t o r was i n c l u d e d i n t h i s new e q u a t i o n t o account •for t h e d i f f e r e n c e s i n egg component y e i l d r e l a t i v e t o egg wei g h t . T h i s new e q u a t i o n was e v a l u a t e d a g a i n s t t h e same f u l l c y c l e p r o d u c t i o n d a t a as were t h e Emmans', McDonald and NRC e q u a t i o n s and was found t o be a b l e t o p r e d i c t M.E. i n t a k e w i t h g r e a t e r a c c u r a c y . A l l f o u r p r e d i c t i o n models (Emmans 1974, McDonald 1978, NRC 1981 and Dornan) were then f u r t h e r e v a l u a t e d u s i n g t h r e e i n d i v i d u a l s e t s of e x p e r i m e n t a l f l o c k p r o d u c t i o n d a t a . The Dornan e q u a t i o n , i n a l l c a s e s , was found t o be s u p e r i o r i n i t s a b i l i t y t o p r e d i c t M e t a b o l i z a b l e Energy i n t a k e of l a y i n g c h i c k e n s i n p r o d u c t i o n . i v I would l i k e t o e x p r e s s my s i n c e r e a p p r e c i a t i o n t o Dr. D.B. Bragg and P r o f . Et. E. March f o r t h e a d v i c e , g u i d a n c e and encouragement a f f o r d e d me d u r i n g t h e c o u r s e of t h i s s t u d y . I would a l s o l i k e t o thank my i n d u s t r y c o l l e g u e , Dr. Hugh Saben f o r h i s c o n f i d e n c e , i n s p i r a t i o n and p e r s i s t e n c e which has been i n s t r u m e n t a l i n my c o m p l e t i n g t h e s e s t u d i e s . I would l i k e t o thank Mr. Jack H i n d l e y f o r f i r s t o f f e r i n g me t h e c h a l l e n g e and o p p o r t u n i t y t o e n t e r t h i s f i e l d . I would l i k e t o thank Dr. Danny Hooge of t h e Southern S t a t e s Research O r g a n i z a t i o n f o r k i n d l y s h a r i n g h i s r e s e a r c h d a t a w i t h me. I would l i k e t o thank my w i f e , J u d i t h , my f a m i l y and my f r i e n d s f o r t h e i r encouragement, u n d e r s t a n d i n g and s u p p o r t d u r i n g my y e a r s of s t u d y . L a s t l y , I would l i k e t o thank t h e management of E a s t C h i l l i w a c k Co-op and C a r g i l l N u t r ena Feeds f o r a l l o w i n g me t h e l a t i t u d e t o pursue t h e s e s t u d i e s w h i l e i n t h e i r employ. V TABLE OF CONTENTS PAGE INTRODUCTION 1 REVIEW OF THE LITERATURE HISTORY 3 METABOLIZABLE ENERGY 6 ENERGY PARTITIONING 8 EATING TO ENERGY REQUIREMENT 9 ENERGY CONSERVATION 11 FACTORS AFFECTING M.E. VALUES 12 FACTORS AFFECTING M.E. REQUIREMENT 17 MODELS FOR ESTIMATING ENERGY REQUIREMENT 20 EXPERIMENT #1 MATERIALS AND METHODS 29 RESULTS 32 DISCUSSION 36 EXPERIMENT #2 MATERIALS AND METHODS 39 RESULTS 41 DISCUSSION 43 EXPERIMENT #3 MATERIALS AND METHODS 44 v i P A G E R E S U L T S 4 6 D I S C U S S I O N 5 7 SUMMARY 5 9 B I B L I O G R A P H Y 6 0 A P P E N D I X 6 8 v i i LIST OF TABLES TABLE PAGE I. E q u a t i o n s t o p r e d i c t t h e m e t a b o l i s -a b l e energy r e q u i r e m e n t s o-f l a y i n g c h i c k e n s . ( E x p e r i m e n t #1) 31 I I . Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Emmans (1974), McDonald (1978) and NRC (1981) e q u a t i o n s . ( E x p e r i m e n t #1) ... 33 I I I . The Dornan e q u a t i o n f o r t h e p r e d i c t i o n of m e t a b o l i z a b l e energy r e q u i r e m e n t of l a y i n g c h i c k e n s . (Experiment #2) 40 IV. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Dornan e q u a t i o n . (Experiment #2) 42 V. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k LB2-PF6 u s i n g t h e Emmans (1974), McDonald (1978), NRC (1981) and Dornan e q u a t i o n s . (Experiment #3). 46 VI. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e Emmans (1974), McDonald (1978), NRC (1981) and Dornan e q u a t i o n s . ( E x p e r i m e n t #3) 47 V I I . Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e Emmans (1974), McDonald (1978), NRC (1981) and Dornan e q u a t i o n s . ( E x p e r i m e n t #3) 47 V I I I . S t a t i s t i c a l summary. Comparison of mean d e v i a t i o n s and s t a n d a r d d e v i a t i o n s . (Experiment #3) 48 v i i i APPENDIX TABLE PAGE I. F l o c k p r o d u c t i o n d a t a f o r t h e Dekalb XL-Link commercial l a y i n g c h i c k e n 68 I I . F l o c k p r o d u c t i o n d a t a f o r t h e H y - l i n e W-77 commercial l a y i n g c h i c k e n ........ 69 I I I . Combined f l o c k p r o d u c t i o n d a t a f o r t h e Dekalb XL-Link and H y - l i n e W-77 commercial l a y i n g c h i c k e n 70 IV. P r o d u c t i o n d a t a f o r e x p e r i m e n t a l f l o c k L82-PF6 71 V. P r o d u c t i o n d a t a f o r e x p e r i m e n t a l f l o c k L82-PF17 72 VI. P r o d u c t i o n d a t a f o r e x p e r i m e n t a l f l o c k L76-G41 73.1. i x LI§I_OF_FIGlJRES FIGURE PAGE 1. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Emmans <1974) e q u a t i o n . (Experiment #1) 32 2. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e McDonald (1978) e q u a t i o n . (Experiment #1) 34 3. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e NRC (1981) e q u a t i o n . (Experiment #1) 35 4. Comparison of p r e d i c t e d M..E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Dornan e q u a t i o n . (Experiment #2) 41 5. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF6 u s i n g t h e Emmans (1974-M) e q u a t i o n . ( E x p e r i m e n t #3) 49 6. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e Emmans (1974-M) e q u a t i o n . (Experiment #3) 49 7. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e Emmans (1974-M) e q u a t i o n . (Experiment #3) 50 8. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF6 u s i n g t h e McDonald (1978) e q u a t i o n . (Experiment #3) 51 9. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e McDonald (1978) e q u a t i o n . (Experiment #3) 51 X FIGURE PAGE 10. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e McDonald (1978) e q u a t i o n . (Experiment #3) 52 11. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF6 u s i n g t h e NRC (1981) e q u a t i o n . (Experiment #3) 53 12. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e NRC (1981) e q u a t i o n . (Experiment #3) 53 13. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l , f l o c k L76-G41 u s i n g t h e NRC (1981) e q u a t i o n . (Experiment #3) 54 14. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k LB2-PF6 u s i n g t h e Dornan e q u a t i o n . (Experiment #3) 55 15. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e Dornan e q u a t i o n . (Experiment #3) 55 16. Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e Dornan e q u a t i o n . (Experiment #3) 56 x i " E n e r g y i s a n a b s t r a c t i o n t h a t c a n b e m e a s u r e d o n l y i n i t s t r a n s - f o r m a t i o n f r o m o n e f o r m t o a n o t h e r . " I n : N u t r i t i o n a l E n e r g e t i c s o f D o m e s t i c A n i m a l s N a t i o n a l A c a d e m y P r e s s W a s h i n g t o n , D . C . 1 9 8 1 INTRODUCTION P r o g r e s s i v e improvements i n t h e b r e e d i n g and n u t r i t i o n of p o u l t r y over t h e p a s t f i f t y y e a r s have r e s u l t e d i n c h i c k e i meat and eggs b e i n g among t h e l e a s t e x p e n s i v e h i g h q u a l i t y p r o t e i n p r o d u c t s a v a i l a b l e today. A l t h o u g h g e n e t i c improve-ment has been a v e r y l a r g e f a c t o r , much of t h e b e n e f i t we reap t o d a y has been t h e r e s u l t of t h e tremendous advances i n t h e f i e l d of n u t r i t i o n . The e a r l y work of F r a p s (1746) and S c o t t e t a l . (1947) i n i t i a t e d t h e s t u d i e s which e v e n t u a l l y i d e n t i f i e d energy as a major c o n t r i b u t i n g f a c t o r i n n u t r i e n t u t i l i z a t i o n and e f f i c i e n c y . The r e c o g n i t i o n of t h e f a c t t h a t c h i c k e n s t e n d t o eat t o meet t h e i r energy r e q u i r e m e n t s ( P e t e r s o n e t a l . 1954) has made i t p o s s i b l e t o f o r m u l a t e d i e t s by r e l a t i n g t h e l e v e l s of a l l o t h e r n u t r i e n t s t o t h e energy l e v e l . I d e n t i f i c a t i o n of t h e p h y s i o l o g i c a l and e n v i r o n -mental f a c t o r s which a f f e c t t h e energy r e q u i r e m e n t s has r e s u l t e d i n d i e t f o r m u l a t i o n s which meet more e f f i c i e n t l y t h e s p e c i f i c n u t r i e n t r e q u i r e m e n t s of t h e c l a s s of p o u l t r y b e i n g f e d . Due t o i n c r e a s i n g c o s t of energy, p a r t i c u l a r l y from foo d r e l a t e d i n g r e d i e n t s , a g r e a t d e a l of e x p e r i m e n t a l work has been done t o i n v e s t i g a t e t h e energy r e q u i r e m e n t s of p o u l t r y over a wide range o f ' c o n d i t i o n s . S e v e r a l i n v e s t i g -a t i o n s have i n c o r p o r a t e d o b s e r v a t i o n s i n t o f a c t o r i a l .equations i n an attempt t o p r e d i c t a mathematical model f o r t h e r e l a t i o n -s h i p of m e t a b o l i c energy r e q u i r e m e n t and p h y s i o l o g i c a l r e s p o n s e The work r e p o r t e d h e r e i n was conducted t o i n v e s t i g a t e t h e f e a s i b i l i t y and a c c u r a c y of a p r e d i c t i v e model t o e s t i m a t e t h e m e t a b o l i z a b l e energy r e q u i r e m e n t s of l a y i n g c h i c k e n s a t v a r i o u s l e v e l s of m e t a b o l i c a c t i v i t y , t o d e t e r m i n e t h e f a c t o r s r e l a t i n g p r e d i c t i o n e r r o r s and t o d e v e l o p a p r e d i c t i o n model s u i t a b l e t o t h e c o n t i n u o u s l y changing c o n d i t i o n s i n t h e environment, p h y s i o l o g y and r e s u l t i n g p r o d u c t REVIEW OF THE LITERATURE HISTORY The - f i r s t e x p e r i m e n t s on t h e r o l e of energy i n p o u l t r y n u t r i t i o n were s t i m u l a t e d by t h e s t u d i e s of F r a p s (1946) which i n d i c a t e d a wide v a r i a t i o n i n t h e p r o d u c t i v e energy c o n t e n t of p o u l t r y f e e d i n g r e d i e n t s . The more f i b r o u s f e e d s tended t o be lower i n energy c o n t e n t . C h i c k performance was soon found t o be markedly a f f e c t e * by t h e energy l e v e l of t h e r a t i o n . S c o t t , M a t t e r s o n and S i n g s e n (1947) developed a h i g h energy b r o i l e r r a t i o n by s u b s t i t u t i n g wheat and c o r n f o r more f i b r o u s i n g r e d i e n t s i n t h e r a t i o n such as o a t s and b y - p r o d u c t s of wheat m i l l i n g . The h i g h energy r a t i o n r e s u l t e d i n i n c r e a s e d r a t e of growth and improved f e e d e f f i c i e n c y . I t was observed t h a t f i b r e eer se was not r e q u i r e d f o r t h e p h y s i o l o g i c a l w e l l b e i n g of t h e c h i c k . I t had been noted p r e v i o u s l y t h a t c h i c k performance was a f f e c t e d by t h e f i b r e c o n t e n t of t h e r a t i o n . Heuser e t a l . (1944) o b s e r v e d t h a t t h e more f i b r o u s f e e d s such as o a t s and wheat b y - p r o d u c t s were l e s s e f f i c i e n t f o r growth and main-tenance of body weight than l e s s f i b r o u s f e e d s such as wheat c o r n and r o l l e d o a t s . F o l l o w i n g t h e d i s c o v e r y of t h e e f f i c a c y of h i g h energy r a t i o n s ( S c o t t e t a l . , 1947), o t h e r workers demonstrated t h a t performance was a f f e c t e d by t h e f i b r e c o n t e n t of t h e r a t i o n . Panda and Combs (1950) c o n c l u d e d t h a t t h e growth d e p r e s s i n g e f f e c t of a d d i t i o n a l c rude f i b r e from wheat, wheat b r a n , wheat m i d d l i n g s , d e h y d r a t e d a l f a l f a meal, p u l v e r i z e d heavy o a t s or ground c o r n cobs, when r e p l a c i n g c o r n i n a r a t i o n , was due t o t h e i r lower p r o d u c t i v e energy c o n t e n t . Dansky and H i l l (1951) observed t h a t growth r a t e was reduced by a d d i t i o n of h i g h l e v e l s of c e l l o p h a n e , sugar cane p u l p or c e l l u l o s e t o a r a t i o n i n i n v e r s e p r o p o r t i o n s t o t h e b u l k of t h e r a t i o n . I t soon became apparent t h a t energy l e v e l of r a t i o n s e x e r t e d a p r o f o u n d i n f l u e n c e on t h e performance of c h i c k s . H i l l and Dansky (1954) o b s e r v e d t h a t as energy l e v e l of a r a t i o n was reduced by a d d i t i o n of oat h u l l s and, a t c o n s t a n t p r o t e i n l e v e l s , growth r a t e was reduced but f e e d consumption was not a f f e c t e d . S h o r t l y t h e r e a f t e r , i t was r e c o g n i z e d t h a t a l t h o u g h an i n v e r s e r e l a t i o n s h i p u s u a l l y e x i s t e d between t h e f i b r e l e v e l of a r a t i o n and i t s energy c o n t e n t , t h e two f a c t o r s were not n e c e s s a r i l y i n t e r d e p e n d e n t . R i c h a r d s o n , Watts and Epps (1958) noted t h a t a d d i t i o n a l f i b r e from r i c e h u l l s reduced f e e d e f f i c i e n c y a l t h o u g h i t d i d not a f f e c t weight g a i n . The e f f e c t of t h e a d d i t i o n a l f i b r e on f e e d e f f i c i e n c y c o u l d be n u l l i f i e d by s u p p l e m e n t i n g t h e r a t i o n w i t h f a t . L e v e l of p r o d u c t i v e energy i n t h e r a t i o n was found t o be h i g h l y c o r r e l a t e d w i t h f e e d e f f i c i e n c y and a b e t t e r c r i t e r i o n of t h e worth of a r a t i o n than e i t h e r r a t i o n or c a l o r i c d e n s i t y . 6. MIIABQLIZAJBL^ The p o u l t r y i n d u s t r y r e l i e d on p r o d u c t i v e energy v a l u e s t o d e f i n e energy r e q u i r e m e n t s and t o d e s c r i b e t h e a v a i l a b l e energy i n f e e d s t u f f s f o r many y e a r s . P r o d u c t i v e energy i s a form of net energy and i s d e t e r m i n e d by measuring t h e energy s t o r e d as f a t and p r o t e i n i n growing or f a t t e n e d b i r d s ( F r a p s , 1946). T h i s a s s a y i s r e l a t i v e l y d i f f i c u l t because i t i n v o l v e s measuring weight change, f e e d i n t a k e , and change i n c a r c a s s c o m p o s i t i o n . Attempts have been made t o measure d i g e s t i b l e energy v a l u e s i n b i r d s , but t h e s e a r e f u r t h e r c o m p l i c a t e d by t h e e x c r e t i o n of f e c e s and u r i n e v i a a common c l o a c a . S u r g i c a l t e c h n i q u e s have been used t o p e r m i t t h e s e p a r a t i o n of f e c e s from u r i n e but t h e r e can be no p r o o f t h a t a m o d i f i e d b i r d behaves i n t h e same manner as a normal b i r d . D avidson, McDonald and W i l l i a m s (1957) c o n c l u d e d t h a t t h e p r o d u c t i v e energy v a l u e s of F r a p s (1946) were u n r e l i a b l e due t o i n c o n s i s t e n c i e s i n t h e a l g e b r a i c c a l c u l a t i o n i n v o l v e d . M e t a b o l i z a b l e energy v a l u e s have been measured w i t h p o u l t r y f o r many y e a r s but i t was not u n t i l about 1960 t h a t t h e y became w i d e l y a c c e p t e d . Anderson, H i l l and Renner (1958), H i l l and Anderson (1958) and P o t t e r e t a l . (1960) observed t h a t M.E. v a l u e s were a more p r e c i s e measure of energy than p r o d u c t i v e energy v a l u e s because of t h e g r e a t e r degree of v a r i a b i l i t y t h a t e x i s t e d i n t h e measurement of p r o d u c t i v e energy. Vohra (1966) a l s o c o n c l u d e d t h a t M.E. was a b e t t e r i n d i c a t o r of n u t r i t i v e v a l u e of a r a t i o n than net energy. In t h e measurement of m e t a b o l i z a b l e energy t h e gaseous p r o d u c t s of d i g e s t i o n a r e i g n o r e d , but c o r r e c t i o n i s u s a l l y made f o r n i t r o g e n g a i n e d or l o s t d u r i n g a s s a y . ME = IE - (FE + UE - kRN) WHERE: ME = M e t a b o l i z a b l e energy IE = Energy i n t a k e FE = F e c a l energy UE = U r i n a r y energy RN = R e t a i n e d n i t r o g e n Two c o n s t a n t s have been w i d e l y used; 8.22 k c a l / g of n i t r o g e n , which was d e r i v e d from t h e g r o s s energy v a l u e of u r i c a c i d , and 8.73 k c a l / g , which was c a l c u l a t e d from th e g r o s s energy v a l u e s of t h e v a r i o u s n i t r o g e n o u s compounds of c h i c k e n u r i n e ( T i t u s e t a l . , 1 9 5 9 ) . 8. ENERGY.PARJIJIONING L a v o i s i e r d u r i n g t h e e i g h t e e n t h c e n t u r y f i r s t e n u n c i a t e d t h e p r i n c i p l e s of combustion both o u t s i d e and w i t h i n t h e body ( B l a s t e r , 1956). In 1884, M. Rubner working w i t h dogs f i r s t demonstrated t h a t t h e fundamental laws of thermodynamics a p p l y t o an i n t a c t l i v e animal system ( B l a x t e r , 1962). The d a i l y m e t a b o l i z a b l e energy r e q u i r e m e n t and i t s p a r t i t i o n i n g i n t o i t s v a r i o u s f r a c t i o n s a r e of both s c i e n t i f i c and economic i m p o r t a n c e . M.E. r e q u i r e m e n t can be f r a c t i o n e d i n t o t h e energy a s s o c i a t e d w i t h maintenance, t h e energy a s s o c i a t e d w i t h changes i n body weight (gro w t h ) , and t h e energy a s s o c i a t e d w i t h egg p r o d u c t i o n . The maintenance energy r e q u i r e m e n t i s a term e q u i v a l e n t t o t h e t o t a l heat p r o d u c t i o n . P o r t i o n s of heat produced a r e needed f o r a) maintenance of b a s a l m e t a b o l i c r a t e , b) a c t i v i t y , and, c) heat i n c r e m e n t . As no p r e c i s e i n f o r m a t i o n i s a v a i l a b l e on b a s a l m e t a b o l i c r a t e , heat increment and a c t i v i t y under p r a c t i c a l c o n d i t i o n s , t h i s t o t a l heat o u t p u t i s termed as maintenance energy. EATING_ig_ENERGY_REQ^ In g e n e r a l , t h e hen i s a b l e t o a d j u s t her f e e d i n t a k e t o m a i n t a i n a c o n s t a n t m e t a b o l i z a b l e energy i n t a k e , as d e t e r m i n e d by her c u r r e n t m e t a b o l i c a c t i v i t y , over a wide range of M.E. l e v e l s i n t h e d i e t (Cowlishaw and E y l e s , 1958; Hewang and V a v i c h , 1962). H i l l (1956), u s i n g p r o d u c t i v e energy, showed a s i m i l a r r e l a t i o n s h i p . P e t e r s o n , Graw and Peek (1954) had p r e v i o u s l y noted t h a t t h e need f o r energy was t h e p r i m a r y f a c t o r c o n t r o l l i n g v o l u n t a r y f e e d i n t a k e i n young c h i c k e n s and had s u g g e s t e d t h a t c h i c k e n s eat t o s a t i s f y t h e i r energy r e q u i r e m e n t s . Dansky and H i l l (1951) had demonstrated t h e c h i c k s 7 a b i l i t y t o compensate f o r reduced d i e t a r y energy by i n c r e a s i n g f e e d consumption. T h i s r e l a t i o n s h i p has a l s o been demonstrated more r e c e n t l y by Ivy and G l e a v e s (1976), Vohra, W i l s o n and S i o p e s (1979), and by R e i d and M a i o r i n o (1980). D i e t a r y b u l k a t low M.E. l e v e l s may l i m i t t h e a b i l i t y of t h e hen t o s a t i s f y her M.E. needs a l t h o u g h Cowlishaw and E y l e s (1958) found t h e hen a b l e t o consume 170 g of low M.E. d i e t per day. G l e a v e s e t a l . , (1963) obse r v e d t h a t hens were a b l e t o consume 550 ml of low d e n s i t y d i e t per day. M o r r i s (1968) obs e r v e d t h a t t h e b i r d d i d not n e c e s s a r i l y make a p r e c i s e adjustment of f e e d i n t a k e when d i e t a r y c o n c e n t r a t i o n of M.E. was i n c r e a s e d , but foun d , r a t h e r , t h a t t h e hen a d j u s t e d her f e e d i n t a k e t o m a i n t a i n c o n s t a n t M.E. i n t a k e o n l y i f t h e d i e t s c o n t a i n e d c l o s e t o 2.7 K c a l / g . I f t h e M.E. l e v e l of t h e d i e t was h i g h e r than t h i s , or i f t h e M.E. r e q u i r e m e n t was h i g h because of l a r g e body s i z e or h i g h r a t e of l a y , t h e b i r d s over—consumed M.E., t e n d i n g t o m a i n t a i n a c o n s t a n t f e e d i n t a k e r a t h e r than a c o n s t a n t M.E. i n t a k e . 11. ENERGY_CONSERyATION The hen a d j u s t s t o cha n g i n g M.E. i n t a k e t h r o u g h changes i n body w e i g h t , r a t e of l a y and egg weight. Cowlishaw and E y l e s (1958) -found t h a t t h e hens -fed h i g h - f i b r e d i e t s compensated -for t h e low M.E. i n t a k e by reduced weight g a i n . Heywang and V a v i c h (1962) showed t h a t t h e hen g a i n e d more weight when -fed h i g h energy d i e t s , and compensated f o r reduced M.E. i n t a k e i n summer by l o s s of weight and reduced egg p r o d u c t i o n . Macleod, T u l l e t t and J e w e i t t (1979) showed t h a t l a y e r s r e c e i v i n g 80% of t h e i r ad l i b i t u m M.E. i n t a k e has lower d a i l y egg mass ou t p u t and 20% lower body w e i g h t s . Kovac (1977) demonstrated t h a t body weight i n c r e a s e d w i t h i n c r e a s i n g d i e t a r y energy w i t h no e f f e c t on egg and s h e l l w e i g h t s . R e i d , V a l e n c i a and M a i o r i n o (1978) found t h a t r e s t r i c t i n g M.E. i n t a k e caused a r e d u c t i o n i n body weight but found no e f f e c t on egg p r o d u c t i o n , egg weight nor c o n v e r s i o n of f e e d t o egg mass by a d j u s t i n g c a l o r i c d e n s i t y between 3.08 and 2.42 K c a l / g . EAQIQRS_AFFECTING_^ A d o p t i o n of m e t a b o l i z a b l e energy as t h e p r e f e r r e d measure of energy i n p o u l t r y n u t r i t i o n l e d t o i n v e s t i g a t i o n of f a c t o r s a f f e c t i n g M.E. v a l u e s and measurement. B a l d i n i (1960) i n d i c a t e d t h a t t h e M.E. l e v e l of a m e t h i o -n i n e - d e f i c i e n t r a t i o n was h i g h e r than t h a t of a b a l a n c e d r a t i o n Carew and H i l l (1961) c o u l d f i n d no e f f e c t of a m e t h i o n i n e d e f i c i e n c y on M.E.. S i b b a l d , S l i n g e r and Pepper (1962) a l s o found no e f f e c t of amino a c i d s on t h e M.E. c o n t e n t of a r a t i o n . O lson e t a l . (1961) noted a d e c r e a s e i n t h e M.E. c o n t e n t of meat meal as t h e l e v e l of i n c l u s i o n of meat meal i n t h e r a t i o n i n c r e a s e d but a s i m i l a r e f f e c t c o u l d not be demonstrated w i t h soybean meal. S i b b a l d and S l i n g e r (1962) r e p o r t e d t h a t t h l e v e l of i n c l u s i o n of h i g h p r o t e i n f e e d s t u f f s i n a r a t i o n had no e f f e c t on t h e M.E. c o n t e n t of t h e f e e d s t u f f . S i b b a l d , Summers and S l i n g e r (1959) and S i b b a l d , Summers and S l i n g e r (1960) o b s e r v e d t h a t w h i l e t h e M.E. c o n t e n t of c o r n d i f f e r e d s i g n i f i c a n t l y depending on t h e o t h e r components of t h e r a t i o n , t h a t f o r wheat i t d i d n o t . R e c e n t l y i t was shown t h a t M.E. v a l u e s v a r y w i t h f e e d i n t a k e because t h e m e t a b o l i c -fecal and endogenous urinary-energy l o s s e s a r e charged a g a i n s t t h e f e e d ( S i b b a l d , 1975). T h i s i s of i m p o r t a n c e when f e e d s t u f f s of low p a l a t a b i l i t y a r e b e i n g assayed because i t i s normal t o maximise t h e l e v e l of t h e t e s t m a t e r i a l i n t h e as s a y d i e t . Age of t h e b i r d has been found t o a f f e c t t h e l e v e l of M.E. i n r a t i o n s . S i b b a l d , Summers and S l i n g e r (1959) demon-s t r a t e d t h a t t h e M.E. c o n t e n t of s e v e r a l f e e d s t u f f s d i f f e r e d when c h i c k s 3 or 7 weeks of age were used f o r d e t e r m i n a t i o n s . Z e l e n k a (1968) and L e s s i r e and L e c l e r c q (1982) a l s o r e p o r t e d t h a t t h e M.E. c o n t e n t of r a t i o n s v a r i e s as t h e b i r d s aged. S p e c i e s of b i r d has been found t o a f f e c t t h e l e v e l of M.E. i n r a t i o n s . S l i n g e r , S i b b a l d and Pepper (1964) i n d i c a t e d t h a t d i f f e r e n c e s e x i s t e d between c h i c k e n s and t u r k e y s i n t h e i r a b i l i t y t o m e t a b o l i z e energy from e i t h e r h i g h o r low energy r a t i o n s . These d i f f e r e n c e s were l a t e r c o n f i r m e d by B e g i n (1967) and F o s t e r (1968). H u r w i t z e t a l . (1980) a l s o found t h a t t h e M.E. r e q u i r e m e n t f o r growth v a r i e d between c h i c k e n s and t u r k e y s . They a t t r i b u t e d t h i s s p e c i e s d i f f e r e n c e t o t h e d i f f e r e n c e i n t h e l i p i d c o n t e n t of t h e t i s s u e g a i n e d by t h e b r o i l e r s and p o u l t s a t t h e ages used i n t h e i r s t u d y . B r o i l e r t i s s u e c o n t a i n s about 12% l i p i d s (Edwards e t a l . , 1773), w h i l e t h a t of t u r k e y t i s s u e a t t h e age s t u d i e d c o n t a i n s o n l y 2 t o 3% l i p i d ( H u r w i t z e t a l . , 1980). The s o u r c e of energy has a l s o been shown t o a f f e c t t h e v a l u e of M.E. i n t h e d i e t . S i b b a l d , S l i n g e r and Pepper (196 r e p o r t e d t h a t t a l l o w , soybean o i l and mixed v e g e t a b l e f a t s h s t i m u l a t i n g e f f e c t s on t h e weight g a i n of c h i c k s t h a t c o u l d not be e x p l a i n e d i n terms of v a r i a t i o n s i n d i e t a r y energy v a l u e s . The e f f e c t was a l s o demonstrated i n t h e f e e d e f f i c i e n c y d a t a . In 1966, Touchburn and Naber r e p o r t e d t h a t s u p p l e m e n t a l f a t e l i c i t e d improvements i n f e e d e f f i c i e n c y of growing t u r k e y s t h a t s u r p a s s e d t h o s e e x p e c t e d on t h e b a s i s of i n c r e a s e s i n m e t a b o l i z a b l e energy c o n c e n t r a t i o n of t h e d i e t s . They termed t h i s i n f l u e n c e of f a t t h e " e x t r a - c a l o r i c " e f f e c t . Vermeersch and Vanschoubroek (1968) made a comprehensive r e v i e w of t h e l i t e r a t u r e on t h e use of s u p p l e m e n t a l f a t s i n d i e t s of growing c h i c k s . They 1 c o n c l u d e d t h a t c e r t a i n -fats i n c r e a s e d e f f i c i e n c y of f e e d u t i l i s a t i o n and, i n some c a s e s , weight g a i n t o a h i g h e r degree than would be ex p e c t e d from t h e i r M.E. c o n t e n t . S u b s e q u e n t l y , s e v e r a l r e s e a r c h e r s found t h a t supplement fat< improved f e e d e f f i c i e n c y of growing t u r k e y s c o n s i d e r a b l y more than would be ex p e c t e d from changes i n d i e t a r y M.E. (Jensen e t a l . 1970, P o t t e r , 1976, and Waibel e t a l . 1977.) Jensen e t a l . (1970) e s t i m a t e d t h a t , i f a l l t h e improvement i n f e e d e f f i c i e n c y observed i n t h e i r e x p e r i m e n t s was due t o t h e energy c o n t r i b u t e d t o t h e d i e t by s u p p l e m e n t a l y e l l o w g r e a s e , t h e "adjustment M.E." of t h e f a t would be 10,165 K c a l / k g . T h i s v a l u e was much h i g h e r than t h e 7,709 K c a l of M.E./kg of y e l l o w g r e a s e used i n t h e d i e t f o r m u l a t i o n and exceeded t h e g r o s s energy of t h i s f a t . S e l l e t a l . (1976), Horani and S e l l (1977) and S e l l e t a l . (1979) a l s o d e s c r i b e d u n u s u a l l y l a r g e improvements i n e f f i c i e n c y of f e e d u t i l i z a t i o n of l a y i n g hens when d i e t s based on c o r n , o a t s or b a r l e y were supplemented w i t h 2, 4, or 67. t a l l o w . In t h i s r e s e a r c h , M.E.'s of f a t supplemented d i e t s were measured e x p e r i m e n t a l l y . The "de t e r m i n e d " M.E.' of f a t supplemented d i e t s were observed t o c o n s i s t e n t l y exceed t h e M.E.'s c a l c u l a t e d on t h e b a s i s of r e f e r e n c e n i t r o g e n - c o r r e c t e d , m e t a b o l i z a b l e energy v a l u e s of t h e i n g r e d i e n t s . When t o t a l c r e d i t f o r t h e changes i n dete r m i n e d d i e t a r y M.E.'s was g i v e n t o t h e s u p p l e m e n t a l t a l l o w , e s t i m a t e s of t h e M.E. c o n t e n t of t h i s f a t s o u r c e ranged from 9,300 t o 10,300 K c a l / k g . These e s t i m a t e s . e q u a l l e d or exceeded t h e g r o s s energy f o r t a l l o w . Data p u b l i s h e d by C u l l en e t a l . (1962), Bomez and P o l i n (1974) and Whitehead and F i s h e r (1975) a l s o showed t h a t s u p p l e m e n t a l f a t s caused e x t r a c a l o r i c e f f e c t s i n p o u l t r y d i e t s e q u i v a l e n t t o 9,700 t o 10,500 k c a l M.E./kg of f a t . 17. EAQIQRS_AFFECTINGM Payne (1967) and Smith and O l i v e r (1972 a & b) found t h a t t h e -feed i n t a k e of ad l i b . f e d b i r d s was reduced a t h i g h e n v i r o n m e n t a l t e m p e r a t u r e . Payne (1967) and Mowbray and Sykes (1971) found t h a t up t o about 30*C t h i s r e d u c t i o n i n f e e d i n t a k e was not a s s o c i a t e d w i t h a d e p r e s s i o n of egg p r o d u c t i o n i f t h e i n t a k e of t h e o t h e r n u t r i e n t s o t h e r than t h o s e needed f o r energy was m a i n t a i n e d . P r i n c e e t a l . (1961) obse r v e d t h a t f e e d i n t a k e d e c r e a s e d w i t h i n c r e a s i n g t e m p e r a t u r e i n a l i n e a r f a s h i o n . Emmans and C h a r l e s (1976) found t h a t f e e d i n t a k e d e c r e a s e d w i t h i n c r e a s i n g t e m p e r a t u r e but not l i n e a r l y . The r a t e of d e c r e a s e was f a s t e r a t h i g h e r t e m p e r a t u r e s . A p r o g r e s s i v e d e c r e a s e i n egg weight w i t h i n c r e a s e i n t e m p e r a t u r e was a l s o r e p o r t e d and a t t r i b u t e d t o de c r e a s e d n u t r i e n t i n t a k e as r e f l e c t e d i n t h e reduced f e e d i n t a k e . H u r w i t z e t a l . (1980) o b s e r v e d a l i n e a r r e l a t i o n s h i p between f e e d i n t a k e i n c r e a s i n g t e m p e r a t u r e but demonstrated n o n - l i n e a r r e l a t i o n s h i p s between weight g a i n and t e m p e r a t u r e , f e e d e f f i c i e n c y and t e m p e r a t u r e and r e q u i r e m e n t f o r maintenance and t e m p e r a t u r e . As t h e r a t i o of f e e d i n t a k e i s o b v i o u s l y d e t e r m i n e d by weight g a i n and maintenance, H u r w i t z 18, s u g g e s t e d t h a t t h e l i n e a r appearance of t h e f e e d i n t a k e on t e m p e r a t u r e must, t h e r e f o r e , be a c o i n c i d e n c e r e s u l t i n g from t h e c o m b i n a t i o n of t h e two n o n - l i n e a r f u n c t i o n s . The l i n e a r change i n t h e M.E. r e q u i r e m e n t w i t h t e m p e r a t u r e a l s o assumes t h a t t h e energy r e q u i r e m e n t s f o r both maintenance and p r o d u c t i o n change w i t h t e m p e r a t u r e . B y e r l y e t a l . , (1978) and B a l n a v e e t a l . , (1978) suggest t h a t t h e maintenance term o n l y changes w i t h t e m p e r a t u r e and t h a t t h e energy r e q u i r e d f o r p r o d u c t i o n i s t e m p e r a t u r e independant. B y e r l y e t a l . ( 1 9 7 8 ) r e p o r t e d a d e c l i n e i n f e e d i n t a k e w i t h i n c r e a s i n g t e m p e r a t u r e and a t t r i b u t e d t h i s t o a r e d u c t i o n i n t h e amount of energy r e q u i r e d f o r maintenance. The observed d e c r e a s e i n oxygen consumption ( B a r r o t and P r i n g l e , 1946) and d e c r e a s e i n heat p r o d u c t i o n ( F a r r e l and Swain, 1977) w i t h i n c r e a s e d t e m p e r a t u r e s up t o a p p r o x i m a t e l y 27*C would s u p p o r t B y e r l y ' s h y p o t h e s i s . D a v i s e t a l . , (1973) found t h a t heat p r o d u c t i o n d e c r e a s e d l i n e a r l y as t h e ambient t e m p e r a t u r e i n c r e a s e d . B y e r l y e t a l . ( 1 9 7 8 ) c a l c u l a t e d an i n c r e a s e i n M.E. r e q u i r e m e n t of about 3 K c a l / b i r d / d a y f o r each °C d e c r e a s e 19. i n ambient t e m p e r a t u r e . Emmans (1974) noted a range i n e s t i m a t e s of change i n M.E. f o r maintenance from 0.6 K c a l t o 3.5 K c a l / k g day °C. Emmans e s t i m a t e d a g e n e r a l r e l a t i o n s h i p o f o r w h i t e h y b i r d egg l a y e r s of 2.2 K c a l / k g day C change i n ambient t e m p e r a t u r e . F u r t h e r m o r e , Emmans (1974) suggested t h a t v a r i a t i o n i n t h e comple t e n e s s of f e a t h e r i n g might account f o r much of t h e v a r i a t i o n s r e p o r t e d . Ivy and G l e a v e s (1976), u s i n g hormonal t h e r a p y ( p r o g e s t e r o n e ) t o a d j u s t egg p r o d u c t i o n l e v e l s , demonstrated a h i g h l y s i g n i f i c a n t e f f e c t of egg p r o d u c t i o n upon energy consumption. As egg p r o d u c t i o n l e v e l s were i n c r e a s e d energy consumption i n c r e a s e d i n a l i n e a r f a s h i o n . They c a l c u l a t e d t h a t t h e a d d i t i o n a l M.E. r e q u i r e d , above maintenance, t o produce one egg ( s i z e not s p e c i f i e d ) by hens p r o d u c i n g a t 70.57. was a p p r o x i m a t e l y 160 K c a l . They a l s o c a l c u l a t e d t h e maintenance r e q u i r e m e n t of a l a y i n g hen ( s i z e not s p e c i f i e d ) t o be 156 K c a l M.E. per hen per day. No s i g n i f i c a n t e f f e c t of d i e t a r y p r o t e i n l e v e l upon f e e d consumption was obse r v e d . MQD£iLS_FOR„ES Over t h e y e a r s numerous models have been d e v e l o p e d t o e s t i m a t e t h e needs of v a r i o u s s p e c i e s of p o u l t r y f o r energy. Brody e t a l . , (1938) were among t h e c a l c u l a t e f e e d consumption as a f u n c t i o n growth and egg p r o d u c t i o n . f i r s t t o attempt t o of body w e i g h t , B y e r l y (1941), w o r k i n g w i t h a f l o c k of 102 l a y i n g hens, proposed an e q u a t i o n based upon m e t a b o l i c body s i z e , egg mass and d a i l y l i v e weight g a i n : 0.653 F = 0.523 W + 1.126 AW + 1.135 E where F = g of foo d consumed per day W = body w e i g h t , g. AW = growth, g/day E = g of egg/day M o r r i s (1968) remarked t h a t t h e B y e r l y e q u a t i o n has "proven r e m a r k a b l y s u c c e s s f u l over t h e y e a r s i n p r e d i c t i n g d a i l y f o o d i n t a k e of a f l o c k of b i r d s " . However, M o r r i s (1968) a l s o i n d i c a t e d t h a t when t h e B y e r l y e q u a t i o n was f i t t e d t o some p u b l i s h e d d a t a an o v e r - e s t i m a t e of food i n t a k e of 157. was ob s e r v e d . Combs (1962), m o d i f i e d t h e B y e r l y (1941) e q u a t i o n and proposed t h a t t h e d a i l y M.E. i n t a k e of l a y i n g c h i c k e n s c o u l d be p r e d i c t e d by t h e e q u a t i o n : 0. 653 C = 1.52 W + 3.26 G + 3.29 E >: R where C = d a i l y M.E. i n t a k e of t h e hen, R e a l . W = average body w e i g h t , g. G = d a i l y weight g a i n , g. E = average egg w e i g h t , g. R = r a t e of l a y , '/. Brown e t a l . , (1967), on t h e o t h e r hand, showed t h a t t h e e q u a t i o n as m o d i f i e d by Combs (1962) o v e r - e s t i m a t e d c a l o r i c i n t a k e on average by 16.5"/ As H i l l (1956) had demonstrated a c y c l i c a l s e a s o n a l v a r i a t i o n i n t h e a c c u r a c y of B y e r l y ' s e q u a t i o n , t h e hen under f a v o u r a b l e c o n d i t i o n s consuming o n l y 94% of t h e f e e d p r e d i c t e d by Combs, Thomas (1966) f u r t h e r m o d i f i e d Combs'" e q u a t i o n , m u l t i p l y i n g a l l r e g r e s s i o n c o e f f i c i e n t s by 0.94. 2 2 0.653 C = 1.45 W + 3 . 1 3 6 + 3 . 1 5 E x R M o r r i s (1968), m a i n t a i n i n g t h a t t h e hen a d j u s t e d -feed i n t a k e t o m a i n t a i n c o n s t a n t M.E. i n t a k e o n l y i f t h e d i e t s c o n t a i n e d c l o s e t o 2.7 K c a l / g , proposed t h e e q u a t i o n : Y = Y + (0.5466 Y - 146.6) (X - 2.7) 2.7 2.7 where Y = v o l u n t a r y c a l o r i c i n t a k e ( K c a l M.E./bird/day) Y = v o l u n t a r y c a l o r i c i n t a k e when d i e t 2. 7 c o n t a i n e d 2.7 K c a l / g X = d i e t a r y M.E. l e v e l ( K c a l / g ) . Combs (1968) r e p o r t e d t h a t energy r e q u i r e m e n t s f o r hens exposed t o d i f f e r e n t e n v i r o n m e n t a l t e m p e r a t u r e s c o u l d be p r e d i c t e d as f o l l o w s : 0. 653 M.E. = (1.78 + 0.012 T) (1.45 W ) + 3.13 A W + 3.15 E where M.E. = m e t a b o l i z a b l e energy, K c a l / d a y T = e n v i r o n m e n t a l t e m p e r a t u r e , °C W = body w e i g h t , g. AW = body weight change, g. E = d a i l y egg mass, g. Emmans (1974) p r o v i d e d y e t another p r e d i c t i o n e q u a t i o n •for M.E. i n t a k e which a l s o i n c l u d e d a term -for t h e e f f e c t of te m p e r a t u r e . M.E. = W (a + b T) + 2E + 5 AW where M.E. = M.E. i n t a k e K c a l / b i r d / d a y W = mean p e r i o d body w e i g h t , Kg. T = mean e n v i r o n m e n t a l t e m p e r a t u r e , °C E = egg o u t p u t , g / b i r d / d a y AW = body weight g a i n , g / b i r d / d a y a and b have v a l u e s of 170, 155, and 140 and -2.2, -2.1 and -2.0 r e s p e c t i v e l y f o r w h i t e , t i n t e d and brown egg l a y i n g s t o c k s r e s p e c t i v e l y . Emmans and C h a r l e s (1977), e x p e c t i n g t h a t maintenance r e q u i r e m e n t per Kg/day might depend on f e a t h e r i n g , r e - s t a t e d t h e Emmans (1974) d a t a i n t r o d u c i n g a f a c t o r t o account f o r f e a t h e r l o s s . T h e i r e s t i m a t e i n d i c a t e d about a 97. i n c r e a s e i n M.E. r e q u i r e m e n t f o r each u n i t i n c r e a s e of a s c o r e d e n o t i n g l o s s of f e a t h e r s ; a s c o r e r a n g i n g from one t o s i x (Emmans and C h a r l e s , 1977). McDonald (1978) r e v i e w e d t h i r t e e n M.E. p r e d i c t i o n e q u a t i o n s , a l o n g w i t h t h e c a p a b i l i t y of each t o p r e d i c t t h e a c t u a l M.E. i n t a k e s e n c o u n t e r e d from numerous p u b l i s h e d r e p o r t s . Of n o t a b l e i m p o r t a n c e was t h a t t h e e q u a t i o n s d i f f e r e d a p p r e c i a b l y i n t h e power f u n c t i o n of body w e i g h t , r a n g i n g from 0.653 t o 1.0. S c o t t e t a l . , (1976), however, would suggest t h a t t h e maintenance r e q u i r e m e n t of t h e hen, l i k e most o t h e r a n i m a l s , i s p r o p o r t i o n a l t o body weight t o t h e 0.75 power. McDonald and Bruce (1976), however, p u b l i s h e d an a n a l y s i s i n d i c a t i n g t h a t , f o r t h e range of body w e i g h t s from which t h e i r d a t a were drawn, t h e power was of l i t t l e s i g n i f i c a n c e . McDonald (1978) proposed t h e f o l l o w i n g e q u a t i o n f o r p r e d i c t i n g M.E. i n t a k e i n l a y e r s : 0.75 M.E. = 0.532 W + 14.5 G + 0.20 E x R + 147 where M.E. = d a i l y M.E. i n t a k e , K c a l W = average body w e i g h t , g. G = d a i l y weight g a i n , g. E = average egg w e i g h t , g. R = r a t e of l a y , 7. The v a l u e s o b t a i n e d u s i n g t h i s e q u a t i o n , when compared t o t h e p u b l i s h e d d a t a , produced a c o r r e l a t i o n c o e f f i c i e n t of 0.90 (McDonald 1978). The McDonald (1978) e q u a t i o n does not, however, i n c l u d e a f a c t o r f o r t e m p e r a t u r e , and t h e assumption must be made t h a t t h e a n a l y s i s was r e l a t i v e a t about 22 °C. NRC (1981), u s i n g t h e d a t a accumulated by McDonald (1978) from t h e l i t e r a t u r e , noted t h a t t h e Emmans (1974) e q u a t i o n o v e r - e s t i m a t e d d a i l y M.E. by 18.5 p e r c e n t . The aut h o r o b s e r v e d , however, t h a t by cha n g i n g t h e Emmans (1974) 0. 75 e q u a t i o n t o e s t i m a t e maintenance energy based on W 1.0 o r a t h e r than W , a t 21 C, t h e o v e r - e s t i m a t i o n was reduced t o o n l y 3 p e r c e n t . NRC (1981) d e v e l o p e d t h e f o l l o w i n g e q u a t i o n as a d e r i v a t i o n of t h e Combs (1968) e q u a t i o n : 0.75 A t M.E. = 130 W (1.015) + 5.50 AW + 2.07 EE body w e i g h t , g. d i f e r e n c e between 25 °C and ambient t e m p e r a t u r e , °C growth r a t e of r a t e of l o s s / d a y , g. egg mass, g. T h i s e q u a t i o n was then compared by NRC (1981) t o t h e McDonald (1978) e q u a t i o n and t o t h e m o d i f i e d Emmans (1974) e q u a t i o n f o r a c c u r a c y w i t h r e s p e c t t o McDonald's (1978) d a t a . A l t h o u g h much of t h e d a t a was i n c o m p l e t e and assu m p t i o n s were made w i t h r e s p e c t t o t e m p e r a t u r e s (NRC, 1981), observed and • p r e d i c t e d M.E. i n t a k e s v a r i e d by o n l y 3.0, 1.6 and 3.2 p e r c e n t f o r t h e Emmans (1974, m o d i f i e d ) , McDonald (1978) and NRC (1981) e q u a t i o n s r e s p e c t i v e l y . where W = A t = AW = EE = The d a t a a n a l y s e d by McDonald (1978) and s u b s e q u e n t l y by NRC (1981) was c o l l e c t e d from 16 l o c a t i o n s w o r l d wide, u s i n g d i f f e r e n t b r e e d s , h o u s i n g systems, d i e t s and y e a r s . Breeds ranged -from Bantams t o J e r s e y B l a c k G i a n t s . Housing systems ranged -from open -floor pens t o cages i n c o n t r o l l e d environment houses. (McDonald. 1978) The - f o l l o w i n g i n v e s t i g a t i o n was u n d e r t a k e n t o e v a l u a t e t h e degree of a c c u r a c y w i t h which t h e Emmans (1974, m o d i f i e d ) , McDonald (1978), and NRC (1981) e q u a t i o n s / m o d e l s c o u l d p r e d i c t M.E. i n t a k e f o r modern commercial l a y i n g s t r a i n s , as w e l l as t o s t u d y t h e f a c t o r s i n each e q u a t i o n and c o n d i t i o n s r e l a t e d t o t h e cause of p r e d i c t i o n e r r o r . IXP§RIMENT_#_1 The p r i m a r y i n v e s t i g a t i o n was unde r t a k e n t o s t u d y t h e accuracy w i t h which s e v e r a l of t h e more r e c e n t l y p u b l i s h e d p r e d i c t i o n e q u a t i o n s c o u l d a p p r o x i m a t e t h e M.E. i n t a k e l e v e l s o-f modern commercial l a y e r s t r a i n s . The e q u a t i o n s which were e v a l u a t e d a r e l i s t e d i n T a b l e ( I ) . The e q u a t i o n s a r e s i m i l a r , i n t h a t t h e M.E. r e q u i r e m e n t i s broken i n t o i n c r e m e n t s of Maintenance, Browth and P r o d u c t i o n , but d i f f e r a p p r e c i a b l y i n t h e i r r e l a t i v e w e i g h t i n g of t h e v a r i o u s f r a c t i o n s . The Emmans and NRC e q u a t i o n s c o n t a i n a c o r r e c t i o n f a c t o r f o r ambient t e m p e r a t u r e whereas t h e McDonald e q u a t i o n does n o t . The Emmans e q u a t i o n was used as m o d i f i e d by NRC (1981), changing 0. 75 t h e e q u a t i o n t o e s i m a t e maintenance energy based on W 1.0 r a t h e r than W Data were o b t a i n e d from t h e Layer Management Guides of th e Dekalb XL (Dekalb, 1982) and H y - l i n e W77 ( H y - l i n e , 1982) l a y e r s . In both c a s e s t h e s e f u l l d a t a s e t s a r e com p o s i t e t a b l e s r e p r e s e n t i n g v e r y l a r g e p o p u l a t i o n s of commercial l a y e r s r a i s e d under a v a r i e t y of e n v i r o n m e n t a l c o n d i t i o n s , and s u b s e q u e n t l y o a d j u s t e d t o 22 C. Feed consumption f i g u r e s i n both d a t a s e t s were c o m p i l e d u s i n g a c t u a l f i e l d d a t a . C a l o r i c i n t a k e f i g u r e s i n t h e c a s e of t h e Dekalb XL d a t a were c a l c u l a t e d assuming f e e d used was a medium energy c o r n - s o y d i e t of a p p r o x i m a t e l y 2800 K c a l / k g of M.E. The Dekalb XL management g u i d e i n d i c a t e s v a l i d i t y w i t h i n t h e range of 2750 - 2850 K c a l / k g of M.E. In t h e case of t h e H y - l i n e W77, t h e management g u i d e s p e c i f i e s t h a t t h e f e e d used was 2822 K c a l /kg of M.E. The i n d i v i d u a l d a t a s e t s a r e l i s t e d i n Appendix T a b l e s I and I I . TABLE I: E q u a t i o n s t o p r e d i c t t h e m e t a b o l i z a b l e energy i n t a k e of l a y i n g c h i c k e n s . 1. EMMANS (1974-MODIFIED) 0. 75 M.E. = W (170 - 2.2 T) + 2.0 E*R + 5.0 G 2. McDONALD (1978) 0. 75 M.E. = 0.532 W + 14.5 G + 0.20 E*R + 147 3. NRC (1981) 0.75 (25-T) M.E. = 130 W (1.015) + 5.5 G + 2.07 E*R WHERE M.E. = METABOLIZABLE ENERGY, KCAL/DAY W = BODY WEIGHT, KG G = DAILY BODY WEIGHT GAIN/LOSS, GM E = EGG WEIGHT, GM R = 7. RATE OF LAY / 100 T = AMBIENT TEMPERATURE, °C For t h e purpose of t h i s e xperiment t h e H y - l i n e W77 and Dekalb XL d a t a were combined and averaged t o y i e l d t h e e x p e r i m e n t a l d a t a base (see Appendix T a b l e I I I ) . R e s u l t B : Each of t h e t h r e e e x p e r i m e n t a l e q u a t i o n s was used t o p r e d i c t M.E. i n t a k e s on a weekly b a s i s over a - f u l l l a y i n g c y c l e . The r e s u l t s were a n a l y s e d and t h e e q u a t i o n s e v a l u a t e d by examining t h e d e v i a t i o n s between t h e p r e d i c t e d and a c t u a l i n t a k e s (Snedecor, 1956). A summary of t h e r e s u l t s i s l i s t e d i n T a b l e I I . The Emmans e q u a t i o n r e s u l t e d (see F i g u r e 1 ) i n a con-s i s t e n t u n d e r e s t i m a t i o n of M.E. r e q u i r e m e n t s , w i t h a mean d e v i a t i o n of 6.197. and a s t a n d a r d d e v i a t i o n of 3.237.. F i g u r e 1: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Emmans (1974) e q u a t i o n <t r> Kr V <I £ a cc u. z o > UJ a ' 2 0 "|| II | || | | i i i i i i i i | i II I I l l M II I I I I I I l l II l l I I l I II I II I 1 I I I II l f 20 25 30 35 40 45 50 55 60 65 70 75 A B E I N W E E K S I I : Comparison o-f p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Emmans (1974), McDonald (1978) and NRC (19B1) e q u a t i o n s . BREED EMMANS McDONALD NRC DATA 1974-M 1978 1981 AGE KCAL KCAL 7. KCAL X ~ KCAL V. WEEKS /DAY /DAY DEVIATION /DAY DEVIATION /DAY DEVIATION 20 211 21 232 22 250 23 264 24 274 25 280 26 281 27 287 28 291 29 295 30 297 31 298 32 298 33 299 34 299 35 301 36 301 37 301 36 301 39 301 40 301 41 301 42 301 43 301 44 302 45 302 46 302 47 302 4B 302 49 302 50 302 51 302 52 302 53 302 54 302 55 302 56 302 57 302 58 302 59 302 60 302 61 302 62 302 63 302 64 302 63 302 66 302 67 302 68 302 69 302 70 302 71 302 72 302 73 302 74 302 75 302 76 302 77 302 78 302 1B6 -11.85 251 8. 19 227 -9.20 255 -3.41 270 -1.46 283 1.07 288 . 2.49 290 1.05 293 0.69 290 -1.69 289 -2.69 293 -1.68 288 -3.36 294 -1. 67 290 -3. 01 294 -2.33 288 -4.32 292 -2.99 290 -3.65 292 -2.99 290 -3. 65 292 -2.99 291 -3. 32 2B6 -4.98 286 -5.30 286 -5.30 290 -3.97 290 -3.97 285 -5.63 2B4 -5.96 284 -5.96 284 -5.96 283 -6.29 287 -4.97 282 -6.62 282 -6. 62 281 -6.95 279 -7.62 285 -5.63 280 -7.28 279 -7.62 277 -B.2B 277 -B. 28 276 -B.61 279 -7.62 275 -B. 94 274 -9.27 273 -9.60 273 -9. 60 271 -10.26 273 -9.60 271 -10.26 270 -10.60 270 -10.60 269 -10.93 269 -10.93 267 -11.39 266 -11.92 266 -11.92 366 73.46 315 121.98 3B4 53.60 3B5 45. 83 369 34.67 358 27. B6 354 25. 9B 340 18. 47 337 15. 81 324 9.83 312 5.05 325 9.06 309 3.69 324 8.36 310 3.68 321 6.64 306 1 . 66 315 4.65 307 1.99 316 4.98 308 2. 33 312 3.63 312 3.65 302 0.33 302 0.00 302 0.00 312 3.31 313 3.64 302 0.00 302 0.00 302 0.00 306 1.32 302 0.00 313 3.64 302 0.00 302 0.00 302 0. 00 302 0.00 313 3. 64 302 0.00 302 0.00 302 o.oo 302 0.00 302 0.00 312 3. 31 302 0.00 302 0.00 302 0.00 302 0.00 302 0.00 302 0.00 302 0.00 302 0.00 302 0.00 301 -0. 33 301 -0.33 301 -0.33 301 -0.33 301 -0.33 207 -2.06 279 20.21 251 0. 46 280 6. 15 296 7.92 309 10.39 314 11.66 313 9.88 319 9. 47 316 7. 16 314 5.70 319 6.92 313 5. 18 320 7.02 316 5. 54 320 6. 44 314 4.30 318 5. 73 315 4.78 318 5.62 316 4. 82 318 5. 49 317 5. 22 312 3.50 312 3. 15 312 3. 29 316 4. 74 315 4. 46 310 2.73 309 2.31 309 2.31 309 2. 46 308 2.04 313 3.49 307 1 .75 307 1. 75 306 1 . 32 305 0.89 311 2.84 305 1.10 304 0. 66 303 0.22 303 0.22 301 -0. 22 304 0. 79 300 -0.51 299 -0. 95 29B -1 . 39 298 -1 . 39 296 -1 . 83 298 -1 . 38 296 -1.B3 295 -2.27 295 -2.27 294 -2.72 294 -2. 72 292 -3.16 291 -3.61 291 -3.61 MEAN DEVIATION: STANDARD DEVIATION! 6. 19 3.23 8. 61 20. 73 3.97 3. 45 The p r e d i c t i o n of energy r e q u i r e m e n t d u r i n g t h e f i r s t few weeks of l a y i s d i f f i c u l t due t o t h e r a p i d l y changing r e q u i r e m e n t as b i r d s come i n t o p r o d u c t i o n . T h e r e f o r e , t h e a r e a of p a r t i c u l a r i n t e r e s t b e g i n s a t about 30 weeks of age. The p r e d i c t e d energy r e q u i r e m e n t shows a p r o g r e s s i v e l y h i g h e r d e v i a t i o n from t h e o b s e r v e d r e q u i r e m e n t as t h e b i r d ages from 30 weeks th r o u g h t o t h e end of i t s p r o d u c t i o n c y c l e . The d e v i a t i o n i s a c o n s i s t e n t and i n c r e a s i n g under— e s t i m a t i o n of t h e observed energy i n t a k e . The McDonald e q u a t i o n g r e a t l y o v e r e s t i m a t e d (see F i g u r e t h e M.E. r e q u i r e m e n t d u r i n g t h e f i r s t 20 weeks of l a y but F i g u r e 2: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e McDonald (1978) e q u a t i o n . 4 3 S z o > - I O •20 'i i i I I I I I I M I I I I I I I I I I 1 I I I I I I I 11 11 I I I I I I I I I I I I I I I I I r i I I I I I II' 20 25 30 35 40 45 50 55 60 65 70 75 A B E I N W E E K S 34. became p r o g r e s s i v e l y more a c c u r a t e as t h e b i r d aged. Once t h e b i r d a t t a i n e d an age of a p p r o x i m a t e l y 40 weeks,the McDonald (1978) e q u a t i o n p r e d i c t s v a l u e s which a r e v e r y c l o s e t o t h e d a t a r e p o r t e d by DeKalb and H y l i n e . Over t h e e n t i r e l a y i n g c y c l e , t h e mean d e v i a t i o n f o r t h e McDonald (1978) e q u a t i o n was 8.61V. but w i t h a s t a n d a r d d e v i a t i o n of 20.75%. The NRC e q u a t i o n tended t o o v e r e s t i m a t e M.E. r e q u i r e m e n t s (see F i g u r e 3) e a r l y i n l a y , and u n d e r e s t i m a t e d r e q u i r e m e n t s l a t e r i n l a y . F i g u r e 3: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e NRC (1981) equat i on. 2 0 o A 1 5 -10 -5 O - 5 -- 1 0 - 1 5 -l l l l l l l f f l lhmi l . . . . l . . •nin 2 0 t r M i i i i 11 IT 11 i i M i i II i i i i i i i i i i i i i i 11 i M 11 i i II i II i 11 M n i i1 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 7 5 A3E I N W E E K S The NRC e q u a t i o n r e s u l t e d i n M.E. p r e d i c t i o n s w i t h a mean d e v i a t i o n of 3.97% and a s t a n d a r d d e v i a t i o n of 3.45%. D i s c u s s i o n : The d e v i a t i o n of p r e d i c t e d M.E. r e q u i r e m e n t from a c t u a l M.E. r e q u i r e m e n t f o r l a y i n g hens i n p r o d u c t i o n as p r e s e n t e d i n F i g u r e s 1, 2 and 3, demonstrate t h e i n a c c u r a c y of t h e energy p r e d i c t i o n models c u r r e n t l y found i n t h e l i t e r a t u r e . When Emmans (1974), McDonald (197B) and NRC (19B1) a r e compared over t h e complete l a y i n g c y c l e , i t becomes o b v i o u s t h a t w h i l e each e q u a t i o n may be a c c u r a t e under c e r t a i n c o n d i t i o n s ( i . e . body w e i g h t , s t a g e of growth, egg weight and r a t e of l a y ) , none i s a c c u r a t e t h r o u g h o u t t h e e n t i r e l a y i n g c y c l e . Emmans' (1974) e q u a t i o n r e s u l t s i n a p r o g r e s s i v e l y g r e a t e r u n d e r e s t i m a t i o n of M.E. i n t a k e as t h e b i r d ages, t h e McDonald (1978) e q u a t i o n g r e a t l y o v e r e s t i m a t e s M.E. i n t a k e d u r i n g t h e e a r l y p a r t of l a y w h i l e t h e NRC (1981) e q u a t i o n o v e r e s t i m a t e s M.E. i n t a k e d u r i n g t h e e a r l y p a r t of l a and u n d e r e s t i m a t e s M.E. i n t a k e d u r i n g t h e l a t t e r s t a g e s of l a y As a l l t h r e e e q u a t i o n s a r e s i m i l a r i n c o n c e p t , t h a t i s , each c o n t a i n s a f a c t o r t o account f o r t h e energy r e q u i r e m e n t f o r maintenance, growth and egg p r o d u c t i o n , i t becomes o b v i o u s t h a t t h e d r a s t i c d i f f e r e n c e s i n t h e p r e d i c t e d r e s u l t s must be a s s o c i a t e d w i t h t h e d i f f e r e n c e s i n t h e e f f i c i e n c y c o n s t a n t s among t h e v a r i o u s e q u a t i o n s r e l a t i v e t o t h e p a r t i t i o n i n g of r e q u i r e m e n t . The McDonald (1978) e q u a t i o n appears t o u n d e r e s t i m a t e t h e e n e r g e t i c e f f i c i e n c y of growth, whereas both t h e Emmans (1974) and NRC (1981) e q u a t i o n s appear i n i t i a l l y t o u n d e r e s t i m a t e t h e e n e r g e t i c e f f i c i e n c y of egg p r o d u c t i o n , but then t o s u b s e q u e n t l y o v e r e s t i m a t e i t . The i m p o r t a n t f e a t u r e of a r e l i a b l e e s t i m a t e of t h e energy r e q u i r e m e n t i s t o p r o v i d e a method t o improve t h e e f f i c i e n c y of egg p r o d u c t i o n . U n r easonable u n d e r e s t i m a t i o n of t h i s r e q u i r e m e n t , as demonstrated by t h e Emmans e q u a t i o n , when used t o f o r m u l a t e d i e t s f o r t h e l a y e r program w i l l l i k e l y s u p p o r t normal development of peak p r o d u c t i o n . However, t h e l i m i t a t i o n of energy a f t e r 30 weeks of age w i l l r e s u l t i n a r a p i d d e c r e a s i n g s l o p e i n t h e egg p r o -u c t i o n c u r v e . A l s o , b i r d s may have d i f f i c u l t y m a i n t a i n i n g both egg s i z e and body weight. O v e r e s t i m a t i o n i n t h e e a r l y p r o d u c t i o n p e r i o d , as demonstrated by c a l c u l a t i o n s u s i n g t h e McDonald e q u a t i o n may cause a r a p i d a c c u m u l a t i o n of a d i p o s e f a t t i s s u e , low peak p r o d u c t i o n f o l l o w e d by low p r o d u c t i v i t y t h r o u g h o u t t h e l a y i n g y e a r . Under most c o n d i t i o n s both p r o d u c t i v i t y and e f f i c i e n c y of f e e d u t i l i z a t i o n w i l l be a d v e r s e l y a f f e c t e d . The NRC (1981) equation, based upon comparison of the c a l c u l a t e d d e v i a t i o n , i s the most s u i t a b l e of the t h r e e e q u a t i o n s t o c a l c u l a t e M.E. requirements f o r normal p r o d u c t i v i t y by the l a y i n g c h i c k e n . In view of the r e s u l t s o b t ained i n Experiment #1, an attempt t o develop a new equation t o p r e d i c t M.E. i n t a k e l a y i n g c h i c k e n s was made i n Experiment #2. 8. E>\E§?r i ment._#2 disttdi.al _§!Qd_Methods In e x p e r i m e n t #2 a new e q u a t i o n was d e r i v e d and l a b e l l e d t h e Dornan e q u a t i o n . T h i s e q u a t i o n was e v a l u a t e d a g a i n s t t h e same d a t a base used t o e v a l u a t e t h e Emmans, McDonald and NRC e q u a t i o n s i n Experiment #1. The Dornan e q u a t i o n (Table I I I ) was d e r i v e d -from a m o d i f i c a t i o n of t h e NRC (1981) e q u a t i o n . The NRC (1981) e q u a t i o n was used as t h e base model not o n l y because i t s u p p l i e d t h e b e s t " f i t " t o t h e d a t a i n Experiment #1, but because i t was t h e most d i r e c t approach t o s e p a r a t i n g out t h e i n c r e m e n t a l r e q u i r e m e n t s . T h i s a l l o w s g r e a t e r ease i n i d e n t i f y i n g how and where t h e v a r i o u s e n v i r o n m e n t a l and p h y s i o l o g i c a l f a c t o r s a f f e c t t h e t o t a l r e q u i r e m e n t s of t h e b i r d . The maintenance energy r e q u i r e m e n t f o r t h e s e breeds i n t h e 0.75 ' e q u a t i o n was e s t i m a t e d t o be 128 k c a l per W a t 25 C. As w i t h t h e NRC (1981) e q u a t i o n , t h e Dornan e q u a t i o n u t i l i s e s a c o r r e c t i o n of 1.5 p e r c e n t per °C, compounded f o r maintenance, an e f f i c i e n c y of 80 p e r c e n t f o r energy t o be c o n v e r t e d i n t o weight g a i n or eggs, and c a l o r i g e n i c v a l u e s of 4.4 K c a l per gram of t i s s u e and 1.66 K c a l per gram of egg. TABLE I I I : The Dornan e q u a t i o n f o r t h e p r e d i c t i o n of m e t a b o l i z a b l e energy r e q u i r e m e n t of l a y i n g c h i c k e n s . DORNAN 0.75 (25-T) (E-62) ME = 128 W * 1.015 + 5.50 6 +(2.07 # 1 . 0 3 ) * (E*R) WHERE.:. ME = METABOL IZABLE ENERGY, KCAL/DAY W = BODY WEIGHT, KG G = DAILY BODY WEIGHT GAIN/LOSS. GM E = EGG WEIGHT, GM R = V. RATE OF LAY / 100 T = AMBIENT TEMPERATURE, °C The e q u a t i o n d i f f e r s from t h e NRC (1981) e q u a t i o n by t h e a d d i t i o n of a f a c t o r t o account f o r d i f f e r e n c e s i n egg component y i e l d r e l a t e d t o egg weight ( F l e t c h e r e t a l . , 1983). F l e t c h e r r e p o r t e d t h a t y o l k s o l i d s i n c r e a s e d as a r e s u l t of i n c r e a s e d y o l k p e r c e n t a g e y e i l d w i t h i n c r e a s e d egg s i z e . He a l s o r e p o r t e d an i n c r e a s e i n albumin weight and a n u m e r i c a l but n o n - s i g n i f i c a n t i n c r e a s e i n albumin 40. s o l i d s c o n t e n t . From t h e work of Shenstone (1968), d e s c r i b i n g t h e c o m p o s i t i o n of t h e r e l a t i v e components of egg s o l i d s , and u s i n g t h e c a l o r i g e n i c v a l u e s of t h e p r i m a r y egg component c o n s t i t u e n t s , p r o t e i n and l i p i d , a f a c t o r t o account f o r t h i s d i f f e r e n c e i n component y e i l d r e l a t i v e t o egg s i z e . The r e s u l t s of experiment #1 had i n d i c a t e d t h a t t h e NRC (1981) e q u a t i o n a c c u r a t e l y p r e d i c t e d M.E. i n t a k e when t h e egg s i z e was a p p r o x i m a t e l y 62 grams. The c a l c u l a t e d c o r r e c t i o n f a c t o r t o t h e c a l o r i g e n i c c o n s t a n t f o r egg p r o d u c t i o n was, t h e r e f o r e , a p p l i e d per gram d e v i a t i o n from 62 grams. The r e s u l t i n g e q u a t i o n e f f e c t i v e l y a c c e p t s t h e NRC (1981) c a l o r i g e n i c v a l u e of 1.66 k c a l per gram of egg mass when t h e egg weighs 62 grams, but a d j u s t s t h e v a l u e r e l a t i v e t o t h e component y e i l d of eggs of v a r i o u s o t h e r w e i g h t s . 41. R e s u l t s ! The comparison of p r e d i c t e d M.E. i n t a k e u s i n g t h e Dornan (1984) e q u a t i o n t o t h e r e f e r e n c e s o u r c e d a t a i s l i s t e d i n T a b l e ( I V ) . The Dornan e q u a t i o n (see F i g u r e 4) r e s u l t e d i n a mean d e v i a t i o n from t h e " a c t u a l " of 1.717. and a s t a n d a r d d e v i a t i o n of 2.267., i n d i c a t i n g a much b e t t e r " f i t " of t h e p r e d i c t e d energy r e q u i r e m e n t d a t a t o t h e a c t u a l d a t a r e p o r t e d by Dekalb and H y - l i n e . F i g u r e 4: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Dornan e q u a t i o n . « 3 (-« r o c c u . z c > O 2 0 15 -1 0 -5 -- 5 -- 10 -f l -••MJlll—ill*-— -Il|--B||||| - 1 5 - 2 0 Ji i i I I I I l I i I I I i I I ) i i I ) I i I i I I I ) l l I I l I I I I I I I I l l l I l l l l I l I l I I I I I1 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0 6 5 7 0 7 5 A G E I N WEEKS TABLE IV: Comparison o-f p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e u s i n g t h e Dornan e q u a t i o n . BREEDER DATA DORNAN AGE "/. H/D BODY EGG AMBIENT FEED WEEKS PROD WT QMS WT GMS TEMP /DAY 19 1230 22 70 20 2 1300 45 22 75 21 10 1418 46 22 83 22 29 1470 48 22 89 23 53 1520 50 22 94 24 72 1560 50 22 98 25 B4 1593 52 22 100 26 88 1623 52 22 100 27 90 1645 54 22 102 26 91 1665 55 22 104 29 91 1678 56 22 105 30 91 16B5 57 22 106 31 90 1698 57 22 106 32 89 1703 SB 22 106 33 89 1715 38 22 107 34 8B 1720 59 22 107 35 B8 1730 59 22 107 36 87 1733 59 22 107 37 66 1740 60 22 107 38 B6 1743 60 22 107 39 85 1750 60 22 107 40 84 1753 61 22 107 41 B4 1758 61 22 107 42 83 1763 61 22 107 43 82 1763 61 22 107 44 B2 1763 61 22 108 43 81 1763 62 22 108 46 81 176B 62 22 10B 47 BO 1773 62 22 108 48 79 1773 62 22 10B 49 . 78 1773 62 22 108 50 7B 1773 62 22 10B 31 77 1775 62 22 108 52 76 1775 63 22 108 53 76 1780 63 22 108 54 75 17B0 63 22 108 55 75 17B0 63 22 108 56 74 1780 63 22 108 57 73 1780 63 22 108 SB 73 17B5 64 22 10B 39 72 1785 64 22 108 60 71 1785 64 22 108 61 70 1785 64 22 108 62 70 1785 64 22 108 63 69 1785 64 22 108 64 68 1790 64 22 108 65 68 1790 64 22 108 66 67 1790 64 22 10B 67 66 1790 64 22 108 68 66 1790 64 22 108 69 65 1790 64 22 108 70 65 1790 65 22 10B 71 64 1790 63 22 10B 72 63 1790 65 22 108 73 63 1790 65 22 108 74 62 1790 65 22 108 73 62 1790 65 22 108 76 61 1790 65 22 108 77 60 1790 63 22 10B 78 60 1790 65 22 10B KCAL /DAY KCAL •/. /DAY DEVIATION 195 211 232 250 264 274 280 281 287 291 295 297 298 29B 299 299 301 301 301 301 301 301 301 301 301 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 302 202 271 237 260 269 282 283 290 295 294 295 299 297 303 302 307 300 307 304 307 308 310 309 304 304 307 312 311 305 304 304 303 306 311 305 305 304 303 312 306 305 303 303 302 305 301 300 298 298 297 301 300 298 298 297 297 295 294 294 -4.22 16.90 -3. 12 .68 .60 -1 -1 0 1 -0 0.54 1 . 43 91 24 22 -0. 83 0. 45 -O. 39 1 . 47 0. 92 I .84 -0. 27 12 16 02 2.21 88 61 90 57 70 15 B6 14 71 71 O . 87 1.43 87 12 12 68 23 18 42 95 49 -1 -1 -1 0.49 0.02 1.00 O . 30 0. 77 23 23 70 - O . 30 -0.79 -1 -1 -1 -1 - 2 .28 .28 76 . 76 25 74 -2. 74 MEAN DEVIATION! 1.71 STANDARD DEVIATION! 2.2b D i s c y s s i . on|_ The Dornan e q u a t i o n , when compared over t h e e n t i r e l a y i n g c y c l e t o t h e d a t a r e p o r t e d by Dekalb and H y - l i n e , p r e d i c t e d energy r e q u i r e m e n t much b e t t e r than d i d any of t h e Emmans (1774), McDonald (1778) or NRC (1781) e q u a t i o n s . By a d j u s t i n g t h e c a l o r i g e n i c e f f i c i e n c y c o n s t a n t a s s o c i a t e d w i t h t h e p r o d u c t i o n of egg mass t o r e f l e c t t h e d i f f e r e n c e s i n component y i e l d r e l a t i v e t o t h a t of egg mass, t h e Dornan e q u a t i o n s u b s t a n t i a l l y reduced t h e i n i t i a l o v e r e s t i m a t i o n of energy r e q u i r e m e n t e a r l y i n l a y and a l s o t h e subsequent u n d e r e s t i m a t i o n of energy r e q u i r e m e n t l a t e r i n l a y so e v i d e n t w i t h Emmans (1774) and NRC (1781) e q u a t i o n s . In Experiment #3, i n o r d e r t o f u r t h e r s u b s t a n t i a t e t h e v a l i d i t y of t h e Dornan e q u a t i o n , a l l f o u r p r e d i c t i o n e q u a t i o n s (Emmans (1774), McDonald (1778), NRC (1781) and Dornan were t e s t e d a g a i n s t t h r e e i n d i v i d u a l s e t s of a c t u a l f l o c k d a t a . 44. M a t e r i a l I_and_Methgds Three s e t s of d a t a were o b t a i n e d on - f l o c k s s t u d i e d at t h e Southern S t a t e s Research Farm i n P r o v i d e n c e Forge, V i r g i n i a (Dr. Danny Hooge, p e r s o n a l communication). The d a t a s e t s L82 PF6 were -from 5728 Dekalb DK White Leghorn c h i c k e n s i n a s t u d y i n v o l v i n g 16 t r e a t m e n t s , w i t h 2 r e p l i c a t i o n s and 30 eggs per sample. Each p e r i o d o b s e r v a t i o n r e p r e s e n t s a t o t a l sample s i z e o-f 960 eggs, (see Appendix T a b l e V ) . The d a t a s e t s L82 PF17 were c o l l e c t e d from 5728 Hi sex White Leghorns s t u d i e d a t t h e same f a c i l i t y and a l s o i n v o l v e d 16 t r e a t m e n t s w i t h 2 r e p l i c a t i o n s and 30 eggs per sample. (see Appendix T a b l e V I ) . The s e t s L76 G41 were c o l l e c t e d from 1920 H&N N i c k C h i c k White Leghorns. The e x p e r i m e n t a l d e s i g n i n t h i s s t u d y c o n s i s t e d of 16 t r e a t m e n t s , w i t h 2 r e p l i c a t i o n s and 60 b i r d s / p e n . (see Appendix T a b l e V I I ) . The p a r a m e t e r s measured i n t h e s e t h r e e f l o c k s were egg 45. p r o d u c t i o n , body w e i g h t , egg w e i g h t , ambient t e m p e r a t u r e and M.E. i n t a k e . The d a t a were s t u d i e d by i n c o r p o r a t i n g t h e r e l e v a n t p h y s i o l o g i c a l , e n v i r o n m e n t a l and p r o d u c t i v e p a r a m e t e r s i n t o t h e Emmans, McDonald and NRC e q u a t i o n s e v a l u a t e d i n Experiment #1 and i n t o t h e Dornan e q u a t i o n as d e v e l o p e d i n Experiment #2. The p r e d i c t e d M.E. i n t a k e w i t h each e q u a t i o n was compared t o t h e a c t u a l M.E. i n t a k e observed and t h e d e v i a t i o n c a l c u l a t e d f o r each of t h e 12 - 28 day p e r i o d s measured on each f l o c k . Buy i t s ! The c o m p a r i s o n s of p r e d i c t e d M.E. i n t a k e t o a c t u a l M.E. i n t a k e f o r each e q u a t i o n and each f l o c k a r e l i s t e d i n T a b l e s V, VI and V I I . A s t a t i s t i c a l summary of t h e r e s u l t s i s pr e s e n t e d i n T a b l e V I I I . TABLE V: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF6 u s i n g t h e Emmans (1974), McDonald (1978), NRC (1981) and Dornan e q u a t i o n s . ACTUAL EMMANS 2 0 DAY KCAL KCAL X PERIOD /DAY /DAY DEVIATION M C D O N A L D K C A L X / D A Y D E V I A T I O N KCAL X /DAY DEVIATION DORNAN KCAL X /DAY DEVIATION 1 2 3 2 . 2 2 2 3 4 . S 2 4 9 . 3 - 2 . 0 4 3 0 6 . 6 3 2 3 3 . 4 2 3 2 . 0 - 1 . 3 3 2 9 1 . 7 4 2 ( . 7 . 8 2 3 8 . 0 - 3 . 6 6 2 9 9 . 2 S 2 8 7 . 3 2 8 3 . 4 - 0 . 6 6 3 1 7 . 3 6 3 0 9 . 9 2 8 7 . 2 - 7 . 3 2 3 0 3 . 4 7 3 1 4 . 4 2 9 1 . B - 7 . 1 9 3 1 3 . 6 a 3 0 2 . 3 2 7 3 . 4 - 9 . 3 6 2 8 8 . 7 9 2 8 7 . 8 2 7 3 . 3 - 4 . 9 7 2 9 4 . 3 1 0 2 7 2 . 3 2 6 2 . 7 - 3 . 6 0 2 9 3 . 3 11 2 7 8 . 7 2 3 3 . 0 - 8 . 3 0 2 9 8 . 9 1 2 2 8 1 . 2 2 3 4 . 2 - 9 . 6 0 3 0 4 . 7 2 0 . 4 7 2 7 3 . 0 8 . 0 6 2 4 9 . 9 - 1 . 8 1 1 4 . 2 1 2 7 6 . 3 8 . 2 6 2 3 3 . 3 0 . 0 4 1 1 . 7 3 2 8 2 . 4 3 . 4 3 2 6 3 . 1 - 1 . 7 6 1 0 . 3 1 3 0 9 . 6 7 . 7 6 2 9 3 . 6 2 . 1 9 - 2 . 1 0 3 1 0 . 7 0 . 2 6 2 9 9 . 1 - 3 . 4 8 0 . 3 8 3 1 6 . 2 0 . 3 7 3 0 6 . 1 - 2 . 6 4 - 4 . 3 0 2 9 7 . 0 - 1 . 7 3 2 8 9 . 4 - 4 . 2 7 2 . 2 6 2 9 7 . 2 3 . 2 7 2 8 7 . 4 0 . 3 6 7 . 6 3 2 8 6 . 1 4 . 9 9 2 7 6 . 9 1 . 6 1 7 . 2 3 2 7 8 . 3 - 0 . 0 7 2 7 0 . 2 - 3 . 0 3 8 . 3 6 2 7 8 . 4 - t . O O 2 7 1 . 9 - 3 . 3 1 MEAN DEVIATIONi 3.31 B. 13 STANDARD DEVIATIONi 3.29 3.94 3.77 2.25 3.27 1.27 47. TABLE V I : Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k LB2-PF17 u s i n g t h e Emmans (1974), McDonald (1978), NRC (1981) and Dornan e q u a t i o n s . ACTUAL EMMANS MCDONALD NRC DORNAN 2 8 DAY KCAL K C A L X K C A L . X K C A L X K C A L X PERIOD /DAY /DAY D E V I A T I O N /DAY D E V I A T I O N /DAY DEVIATION /DAY D E V I A T I O N 1 2 6 3 . 3 2 2 7 4 . 4 2 7 7 . 4 1 . 0 9 3 2 2 . 2 1 7 . 4 2 3 0 2 . 7 1 0 . 3 1 2 8 2 . 2 2 . 8 4 3 2 9 2 . 4 2 8 2 . 4 - 3 . 4 2 3 0 7 . 4 3 . 13 3 0 7 . 2 3 . 0 6 2 9 7 . 1 1 .61 4 3 0 4 . 4 2 9 0 . 9 - 4 . 4 3 3 1 4 . 3 3 . 3 2 3 1 3 . 9 3 . 7 8 3 0 6 . 6 0 . 7 2 9 3 0 2 . 6 2 9 1 . 7 - 3 . 6 0 3 1 2 . 2 3 . 1 7 - 3 1 6 . 7 4 . 6 6 3 0 9 . 4 2 . 2 3 6 3 1 4 . 2 2 8 8 . 8 -e.oe 3 0 2 . 6 - 3 . 6 9 3 1 3 . 7 - 0 . 16 3 1 0 . 1 - 1 . 3 0 7 3 2 2 . 9 2 8 6 . 7 - 1 1 . 2 1 3 1 6 . 0 - 2 . 14 3 1 2 . 9 - 3 . 10 3 0 9 . 8 - 4 . 0 6 8 3 0 6 . 6 2 8 4 . 6 - 7 . I B 3 1 3 . 9 2 . 3 8 3 1 1 . 1 1 .47 3 1 2 . 9 2 . 0 5 9 3 1 9 . 3 2 7 7 . 3 - 1 3 . 0 9 2 9 6 . 3 - 7 . 2 0 3 0 3 . 4 - 4 . 9 8 3 0 5 . 1 - 4 . 43 10 3 2 2 . 6 2 8 3 . 7 - 1 2 . 0 6 3 2 1 . 1 - 0 . 4 6 3 1 0 . 8 - 3 . 6 6 3 1 2 . 9 - 3 . 0 1 11 3 1 9 . 7 2 7 4 . 4 - 1 4 . 1 7 3 0 9 . 9 - 3 . 0 7 3 0 1 . 8 - 3 . 6 0 3 0 4 . 3 - 4 . 8 2 12 2 9 3 . 3 2 3 9 . 6 - 1 2 . 0 9 3 0 3 . 3 3 . 4 3 2 8 7 . 9 - 2 . 5 1 2 8 8 . S - 2 . 3 0 MEAN D E V I A T I O N ] 8 . 2 2 4 . 6 8 «. 12 2 . 6 7 STANDARD D E V I A T I O N i 4 . 3 6 4 . 3 6 2 . 6 3 1 .32 TABLE V I I : Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e Emmans (1974), McDonald (197B), NRC (1981) and Dornan e q u a t i o n s . ACTUAL EMMANS MCDONALD NRC DORNAN 28 DAY KCAL K C A L X KCAL X KCAL X K C A L X PERIOD /DAY /DAY D E V I A T I O N /DAY D E V I A T I O N /DAY D E V I A T I O N /DAY D E V I A T I O N 1 2 3 2 . 2 2 2 8 4 . 0 2 7 4 . 6 - 3 . 3 1 3 0 2 . 1 6 . 3 7 2 9 6 . 9 4 . 3 4 2 6 9 . 8 - 3 . 0 0 3 3 0 4 . 3 2 9 8 . 4 - 2 . 0 0 3 2 9 . 3 8 . 14 3 2 2 . 3 3 . 8 3 3 0 O . 4 - 1 . 3 3 4 2 9 7 . 3 3 1 6 . 9 6 . 3 9 3 2 6 . 3 9 . 7 3 3 4 2 . 1 1 3 . 0 7 3 2 4 . 1 9 . 0 1 3 3 2 9 . 7 3 2 4 . 6 - 1 . 3 3 3 2 2 . 8 - 2 . 0 9 3 3 0 . 8 6 . 4 0 3 3 3 . 0 1.61 6 3 3 2 . 3 3 3 1 . 2 - 0 . 3 9 3 2 S . 3 - 1 . 2 6 3 3 8 . 3 7 . 7 6 3 4 3 . 4 3 . 8 8 7 2 9 9 . 2 2 8 8 . 3 - 3 . 3 8 2 8 1 . 4 - 3 . 9 3 3 1 1 . 7 4 . IB 3 0 2 . 0 0 . 94 e 3 0 7 . 3 2 8 9 . 8 - 3 . 7 6 3 0 9 . 0 0 . 4 9 3 1 3 . 9 2 . 0 8 3 0 6 . 0 - 0 . 49 9 2 8 9 . 3 2 7 3 . 6 - 4 . 8 0 3 0 3 . 1 3 . 3 9 3 0 0 . 0 3 . 6 3 2 9 4 . 3 1 .73 10 2 9 1 . 3 2 6 4 . 3 - 9 . 3 3 3 0 2 . 9 3 . 9 1 2 8 9 . 3 - 0 . 6 9 2 8 4 . 9 - 2 . 26 11 2 8 2 . 3 2 4 6 . 6 - 1 2 . 6 3 2 8 9 . 8 2 . 6 6 2 7 2 . 2 - 3 . 3 8 2 6 8 . 4 - 4 . 9 2 12 2 6 8 . 0 2 4 8 . 0 - 7 . 4 6 2 8 9 . 0 7 . 8 4 2 7 2 . 4 1 . 6 4 2 6 7 . 7 - 0 . 11 MEAN D E V l A T I O N i 3 . 2 2 4 . 9 0 3 . 0 4 2 . 8 3 STANDARD D E V l A T I O N i 3 . 6 5 3 . 0 3 3 . 9 4 2 . 6 5 48. TABLE V I I I : S t a t i s t i c a l summary. Comparison of mean d e v i a t i ons and s t a n d a r d d e v i a t i o n s . L8 2 PF6 L82 PF17 L76 641 X 5 X s X S Emmans 1974 5.31 3.29 8.22 4.56 5. 22 65 McDonald 1978 8. 71 5. 49 4.68 4.56 4. 90 05 N R C 1981 3.77 3. 27 4. 12 2. 63 5. 04 T m 94 Dornan 2. 25 1.27 2.67 1.32 2. 85 *"> 65 The Emmans (1974) e q u a t i o n (as m o d i f i e d by N R C 1981) c o n s i s t e n t l y u n d e r e s t i m a t e d t h e a c t u a l M.E. i n t a k e f o r a l l t h r e e e x p e r i m e n t a l f l o c k s (see F i g u r e s 5, 6 and 7 ) . As i n Experiment #1, t h e magnitude of t h e d e v i a t i o n tended t o become p r o g r e s s i v e l y g r e a t e r t h r o u g h t h e e x p e r i m e n t a l p e r i od. 49. F i g u r e 5: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF6 u s i n g t h e Emmans <1974-M) e q u a t i o n . 20 <x 3 t-u <r E O CC u. z o t -<I > UJ a 1 5 -10 -- 5 -- 10 - 1 5 --20 T I B 6 7 8 9 2B-DAY L A Y I N G P E R I O D 10 11 12 50. F i g u r e 7: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e Emmans (1974-M) e q u a t i o n . <L D K u E O C£ U. z o -5 - 1 5 -- 2 0 r 5 6 7 8 2 8 - D A Y L A Y I N G P E R I O D 10 T 1 1 12 The McDonald (1976) e q u a t i o n o v e r e s t i m a t e d M.E. i n t a k e i n t h e e a r l y p e r i o d s of l a y , became r e l a t i v e l y a c c u r a t e d u r i n g t h e m i d d l e t h i r d of t h e l a y i n g c y c l e , and tended t o o v e r e s t i m a t e M.E. r e q u i r e m e n t s d u r i n g t h e l a t t e r p e r i o d s of l a y . Comparison of t h e p r e d i c t e d M.E. i n t a k e t o a c t u a l y i e l d e d a mean d e v i a t i o n of 8.137. on f l o c k L82 F'F6, 4.687. on L82 PF17 and 4.907. on L76 G41. (See F i g u r e s 8, 9 and 10). F i g u r e 8: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e -for e x p e r i m e n t a l -flock L82-PF6 u s i n g t h e McDonald (1978) e q u a t i o n . c 3 f-u c E a cc u. z • m a - 1 0 - 1 5 --20 —T-3 e —r-9 10 - I — 11 12 2 8 — D A Y L A Y I N G P E R I O D F i g u r e 9: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e McDonald (1978) e q u a t i o n , -i <x 3 K U <I E O CC u. z o 111 a - 5 --10 8 9 2 8 - D A Y L A Y I N G P E R I O D 10 11 1" 12 52. F i g u r e 10: Comparison o-f p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e McDonald (1978) e q u a t i o n . (-U a r o or u. z o :> UJ o X - 10 --20 r 5 6 7 8 9 2 8 - D A Y L A Y I N G P E R I O D T 10 11 -r 12 The NRC (1981) e q u a t i o n a l s o tended t o o v e r e s t i m a t e t h e M.E. i n t a k e d u r i n g t h e e a r l y p e r i o d s of l a y . S t a t i s t i c a l c o m parisons of t h e d a t a r e s u l t e d i n mean d e v i a t i o n of 3.77% f o r L82 PF6, 4.12% f o r L82 PF17 and 5.04% f o r L76 G41. (See F i g u r e s 11, 12 and 13). F i g u r e 11: Comparison of p r e d i c t e d M.E.' i n t a k e and a c t u a l M.E. i n t a k e -for e x p e r i m e n t a l f l o c k LB2-PF6 u s i n g t h e NRC (1981) e q u a t i o n . <x u <x £ • CC u. z o UJ o - 1 5 -2 8 - D A Y L A Y I N G P E R I O D F i g u r e 12: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L82-PF17 u s i n g t h e NRC (1981) e q u a t i o n . c f-U c E cc LL z o > a 20 15 10 B B H M - 5 -- 1 0 -- 1 5 --20 -T-3 ~r~ 9 10 "1— -11 I— 12 2 8 — D A Y L A Y I N G P E R I O D 5 4 . F i g u r e 1 3 : C o m p a r i s o n of p r e d i c t e d M.E . i n t a k e and a c t u a l M .E . i n t a k e of e x p e r i m e n t a l f l o c k L 7 6 - G 4 1 u s i n g t h e NRC (1981) e q u a t i o n . <x D I-O <£ r o cc u. z • <x •> Ul o -20 5 6 7 8 2 9 — D A Y L A Y I N G P E R I O D The Dornan e q u a t i o n p r e d i c t e d M.E . i n t a k e s w h i c h r e s u l t e d i n a r e l a t i v e l y c l o s e " f i t " t o t h e a c t u a l M .E . i n t a k e t h r o u g h o u t t h e e n t i r e l a y i n g c y c l e f o r a l l t h r e e t e s t f l o c k s . The s t a t i s t i c a l c o m p a r i s o n s of t h e d a t a r e s u l t e d i n mean d e v i a t i o n s f r o m t h e a c t u a l by 2 ,257. f o r L82 F'F6, 2.677. f o r L82 PF17 and 2.857. f o r L76 6 4 1 . (See F i g u r e s 14, 15 and 16) F i g u r e 14: Comparison o-f p r e d i c t e d M.E- i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k LB2-PF6 u s i n g t h e Dornan e q u a t i o n . 2 0 1 5 -<X Q N - - 1 0 -- 1 6 -— 2 0 - 1 — i 1 1 i i 1 1 1 1 1 r ~ 2 3 4 5 6 7 8 9 1 0 1 1 1 2 2 8 - D A Y L A Y I N G P E R I O D 2 8 - D A Y L A Y I N G P E R I O D F i g u r e 16: Comparison of p r e d i c t e d M.E. i n t a k e and a c t u a l M.E. i n t a k e f o r e x p e r i m e n t a l f l o c k L76-G41 u s i n g t h e Dornan e q u a t i o n . <x u u £ • CC z o HH > Ul a - 1 0 --15 -- 2 0 2 8 - D A Y L A Y I N G P E R I O D 57. Discyssi gn:_ The r e s u l t s o b t a i n e d i n Experiment #3, u s i n g a c t u a l e x p e r i m e n t a l f l o c k d a t a , a r e i n v e r y c l o s e agreement t o t h e r e s u l t s o b t a i n e d i n Experiment #1 and #2 u s i n g t h e combined b r e e d e r d a t a . In a l l c a s e s t h e same t r e n d s were ap p a r e n t . As i n Experiment #1, t h e Emmans (1974) e q u a t i o n g e n e r a l l y u n d e r e s t i m a t e d t h e M.E. r e q u i r e m e n t s f o r a l l t h r e e e x p e r i m e n t a l f l o c k s . F u r t h e r m o r e , t h e u n d e r e s t i m a t i o n , a l s o as i n Experiment #1, became p r o g r e s s i v e l y g r e a t e r t h r o u g h t h e l a y i n g c y c l e s . The McDonald (1978) e q u a t i o n , as i n Experiment #1, o v e r e s t i m a t e d t h e M.E. r e q u i r e m e n t s e a r l y i n l a y f o r a l l t h r e e e x p e r i m e n t a l f l o c k s . The NRC (1981) e q u a t i o n , a g a i n , as i n Experiment #1, tended t o o v e r e s t i m a t e M.E. r e q u i r e m e n t s e a r l y i n l a y , become more a c c u r a t e d u r i n g t h e m i d d l e p e r i o d s of l a y , and, near t h e end of l a y , tended t o u n d e r e s t i m a t e M.E. r e q u i r e m e n t s . The Dornan e q u a t i o n more c l o s e l y a pproximated t h e a c t u a l M.E. i n t a k e s t h r o u g h o u t t h e complete l a y i n g c y c l e s 58. •for a l l t h r e e e x p e r i m e n t a l f l o c k s . The Dornan e q u a t i o n , as summarised i n T a b l e V I I I , p r e d i c t e d t h e M.E. r e q u i r e m e n t s w i t h t h e l o w e s t mean d e v i a t i o n s and t h e l o w e s t s t a n d a r d d e v i a t i o n s f o r each of t h e t h r e e t e s t f l o c k s . These d a t a would i n d i c a t e t h a t w h i l e Emmans (1974), McDonald (1978), and NRC (1981) have v a l i d i t y a t c e r t a i n s t a g e s of t h e l a y i n g c y c l e , t h e Dornan e q u a t i o n 0.75 (25-T) E-62 ME = 128 W * 1.015 + 5.5 G + (2.07 * 1.03 )*(E*R> appears t o be b e t t e r a b l e t o p r e d i c t M.E. i n t a k e f o r t h e l a y i n g hens over t h e f u l l l a y i n g c y c l e . 59. Summary Three? p r e d i c t i o n e q u a t i o n s t o de t e r m i n e Metabol i z a b l e Energy (M.E.) i n t a k e i n l a y i n g c h i c k e n s (Emmans 1974, McDonald 1978 and NRC 1981) were t e s t e d a g a i n s t p u b l i s h e d commercial l a y e r p r o d u c t i o n d a t a (Dekalb XL and H y - l i n e W-77). The e q u a t i o n s were t e s t e d by comparing t h e p r e d i c t e d M.E. i n t a k e s t o t h e i n t a k e s as p u b l i s h e d by t h e br e e d e r i n t h e management g u i d e s . A new e q u a t i o n (Dornan) was d e r i v e d and t e s t e d a g a i n s t t h e same s e t o-f d a t a . T h i s new e q u a t i o n was found t o p r e d i c t t h e a c t u a l M.E. i n t a k e more a c c u r a t e l y than t h e Emmans (1974), McDonald (1978) and NRC (1981) e q u a t i o n s . The f o u r e q u a t i o n s were then t e s t e d a g a i n s t t h r e e s e t s of e x p e r i m e n t a l l a y i n g f l o c k d a t a . 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R e l a t i o n s h i p between c h e m i c a l c o m p o s i t i o n and t h e m e t a b o l i z a b l e energy c o n t e n t of p o u l t r y f e e d s t u f f s . P o u l t r y S c i . 41: 1682. S i b b a l d , I.R., and S.J. S l i n g e r . (1962). The m e t a b o l i z a b 1 e energy of m a t e r i a l s f e d t o growing c h i c k s . P o u l t r y S c i . 41: 1612-1613. S i b b a l d , I.R., S.J. S l i n g e r , and W.F. Pepper. (1962). The r e s p o n s e of c h i c k s t o t h e d i e t a r y i n c l u s i o n of m a t e r i a l s which might be assumed t o p o s s e s s b e n e f i c i a l e x t r a c a l o r i c p r o p e r t i e s . P o u l t r y S c i . 41: 1254-1260. S i b b a l d , I.R. (1975). The e f f e c t of f e e d i n t a k e on metabo-l i z a b l e energy v a l u e s measured w i t h a d u l t r o o s t e r s . P o u l t r y S c i . 54: 1990-1997. S l i n g e r , S . J . , I.R. S i b b a l d , and W.F. Pepper. (1964). The r e l a t i v e a b i l i t i e s of two bre e d s of c h i c k e n s and two v a r i e t i e s of t u r k e y s t o m e t a b o l i z e d i e t a r y energy and d i e t a r y n i t r o g e n . P o u l t r y S c i . 43: 329-333. Sm i t h , A . J . , and J . O l i v e r . (1972a). Some n u t r i t i o n a l prob-lems a s s o c i a t e d w i t h egg p r o d u c t i o n a t h i g h e n v i r o n -mental t e m p e r a t u r e s . 1. The e f f e c t of e n v i r o n m e n t a l t e m p e r a t u r e and r a t i o n i n g t r e a t m e n t s on t h e p r o d u c t -i v i t y of p u l l e t s f e d on d i e t s of d i f f e r e n t energy c o n t e n t . Rhod. J . A g r i c . Res. 10, 3. Smit h , A . J . , and J . O l i v e r . (1972b). Some n u t r i t i o n a l prob-lems a s s o c i a t e d w i t h egg p r o d u c t i o n a t h i g h e n v i r o n -mental t e m p e r a t u r e s . 4. The e f f e c t of p r o l o n g e d exposure t o h i g h e n v i r o n m e n t a l t e m p e r a t u r e s on t h e p r o d u c t i v i t y of p u l l e t s f e d on h i g h energy d i e t s . Rhod. J . A g r i c . Res. 10, 43. Snedecor, G.W. (1956). S t a t i s t i c a l „.Methgds... F i f t h E d i t i o n . Iowa S t a t e U n i v e r s i t y P r e s s , Ames, Iowa. Summers, J.D., and S. Leeson. (1978). Energy and p r o t e i n r e q u i r e m e n t s of l a y i n g hens. N u t r i t i o n R e p o r t s I n t e r -n a t i o n a l . 17:1. 87-91. T i t u s , H.W., A.L. M e h r i n g , J r . , D. Johnson, J r . , L.L. N e s b i t t , and T. Tamas. (1959). An e v a l u a t i o n of M.C.F. ( M i c r o - C e l - F a t ) , a new t y p e of f a t p r o d u c t . P o u l t r y S c i . 38: 1114-1119. Thomas, O.P. (1966). S t u d i e s on l y s i n e f o r c h i c k e n s . P r o c . 1966 Md. N u t r i t i o n Conf. p. 80. Touchburn, S.P., and E.C. Naber. (1966). The energy v a l u e of f a t s f o r growing t u r k e y s . P r o c . X l l l t h World's P o u l t r y Congr., K i e v , R u s s i a . 190-195. Vermeersch, B., and F. Vanschoubroek. (1968). The quant-i f i c a t i o n of t h e e f f e c t of i n c r e a s i n g l e v e l s of v a r i o u s f a t s on body weight g a i n , e f f i c i e n c y of f e e d c o n v e r s i o n and f o o d i n t a k e of growing c h i c k e n s . B r i t i s h P o u l t r y S c i . 9: 13-30. Vohra, P. (1966). Energy c o n c e p t s f o r p o u l t r y n u t r i t i o n . World's P o u l t r y S c i . J . 22: 6-24. Vohra, P., W.O. W i l s o n , and T.D. S i o p e s . (1979). Egg p r o -d u c t i o n , -feed consumption and maintenance energy r e q u i r e m e n t s of l e g h o r n hens as i n f l u e n c e d by d i e t a r y energy a t t e m p e r a t u r e s of 15.6 and 26.7 ° C P o u l t r y S c i . 58: 674-680. W a i b e l , P.E., G. Devegowda, and J , P a l a r s k i . (1977). E s t -i m a t i o n of t h e v a l u e of animal f a t i n d i e t s f o r t u r k e y s . P r o c . Minn. N u t r . Conf. pp. 33-46. Whitehead, G.C, and C. F i s h e r . (1975). The u t i l i z a t i o n of v a r i o u s f a t s by t u r k e y s of d i f f e r e n t ages. B r i t i s h P o u l t r y S c i . 16: 481-485. Z e l e n k a , J . (1968). I n f l u e n c e of age of c h i c k e n on t h e m e t a b o l i z a b l e energy v a l u e s of p o u l t r y d i e t s . B r i t i s h P o u l t r y S c i . 9: 135-142. 68. APPENDIX TABLE I F l o c k p r o d u c t i o n f o r t h e Dekalb XL-L i n k commercial l a y i n g c h i c k e n . AGE WEEKS '/. H/D PROD BODY WT GMS EGG WT GRAMS TEMP AVE FEED /DAY KCAL /DAY 2 0 2 . 0 1 3 0 0 4 5 . 0 2 2 6 7 1 8 8 21 1 0 . 0 1 3 7 5 4 6 . 0 2 2 7 6 2 1 3 2 2 3 0 . 0 1 4 4 0 4 7 . 3 2 2 8 5 2 3 8 2 3 5 0 . 0 1 5 0 0 4 8 . 7 2 2 9 3 2 6 0 2 4 7 0 . 0 1 5 4 0 5 0 . 0 2 2 1 0 0 2 8 0 2 5 8 4 . 0 1 5 6 5 5 1 . 5 2 2 101 2 B 3 2 6 8 8 . 0 1 5 8 5 5 2 . 5 2 2 1 0 2 2 8 6 2 7 9 0 . 0 1 6 1 0 5 3 . 7 2 2 1 0 4 2 9 1 2 6 9 1 . 0 1 6 3 0 5 5 . 0 2 2 1 0 6 2 9 7 2 9 9 2 . 0 1 6 4 5 5 5 . B 2 2 1 0 7 3 0 0 3 0 9 2 . 0 1 6 6 0 5 6 . 6 2 2 1 0 8 3 0 2 3 1 9 1 . 5 1 6 7 5 5 7 . 2 2 2 1 0 8 3 0 2 3 2 9 0 . 9 1 6 8 5 5 7 . 7 2 2 1 0 8 3 0 2 3 3 9 0 . 3 1 7 0 0 5 8 . 2 2 2 1 0 B 3 0 2 3 4 8 9 . 7 1 7 1 0 S B . 6 2 2 1 0 8 3 0 2 3 5 8 9 . 1 1 7 2 0 5 9 . 1 2 2 1 0 B 3 0 2 3 6 8 8 . 5 1 7 2 5 5 9 . 5 2 2 1 0 8 3 0 2 3 7 8 7 . 9 1 7 3 0 6 0 . 0 2 2 1 0 8 3 0 2 3 8 8 7 . 3 1 7 3 5 6 0 . 2 2 2 1 0 B 3 0 2 3 9 B 6 . 7 1 7 4 0 6 0 . 5 2 2 1 0 6 3 0 2 4 0 8 6 . 1 1 7 4 5 6 0 . B 2 2 1 0 8 3 0 2 41 8 5 . 5 1 7 5 5 6 1 . 1 2 2 1 0 8 3 0 2 4 2 8 4 . 9 1 7 5 5 6 1 . 4 2 2 1 0 8 3 0 2 4 3 8 4 . 3 1 7 5 5 6 1 . 6 2 2 1 0 8 3 0 2 4 4 8 3 . 7 1 7 5 5 6 1 . 8 2 2 1 0 9 3 0 5 4 5 B 3 . 1 1 7 5 5 6 2 . 0 2 2 1 0 9 3 0 5 4 6 8 2 . 5 1 7 6 5 6 2 . 2 2 2 1 0 9 3 0 5 4 7 8 1 . 9 1 7 6 5 6 2 . 4 2 2 1 0 9 3 0 5 4 8 8 1 . 3 1 7 6 5 6 2 . 6 2 2 1 0 9 3 0 5 4 9 8 0 . 7 1 7 6 5 6 2 . 7 2 2 1 0 9 3 0 5 5 0 8 0 . 1 1 7 6 5 6 2 . 8 2 2 1 0 9 3 0 5 5 1 7 9 . 5 1 7 7 0 6 3 . 0 2 2 1 0 9 3 0 5 5 2 7 8 . 9 1 7 7 0 6 3 . 1 2 2 1 0 9 3 0 5 5 3 7 8 . 3 1 7 7 0 6 3 . 2 2 2 1 0 9 3 0 5 5 4 7 7 . 7 1 7 7 0 6 3 . 3 2 2 1 0 9 3 0 5 5 5 7 7 . 1 1 7 7 0 6 3 . 4 2 2 1 0 9 3 0 5 5 6 7 6 . 5 1 7 7 0 6 3 . 5 2 2 1 0 9 3 0 5 5 7 7 5 . 9 177C) 6 3 . 6 2 2 1 0 9 3 0 5 5 8 7 5 . 3 1 7 7 0 6 3 . 7 2 2 1 0 9 3 0 5 5 9 7 4 . 7 1 7 7 0 6 3 . 8 2 2 1 0 9 3 0 5 6 0 7 4 . 1 1 7 7 0 6 3 . 9 2 2 1 0 9 3 0 5 61 7 3 . 5 1 7 7 0 6 4 . 0 2 2 1 0 9 3 0 5 6 2 7 3 . 9 1 7 7 0 6 4 . 0 2 2 1 0 9 3 0 5 6 3 7 2 . 3 1 7 7 0 6 4 . 1 2 2 1 0 9 3 0 5 6 4 7 1 . 7 1 7 7 0 6 4 . 1 2 2 1 0 9 3 0 5 6 5 7 1 . 1 1 7 7 0 6 4 . 2 2 2 1 0 9 3 0 5 6 6 7 0 . 5 1 7 7 0 6 4 . 2 2 2 1 0 9 3 0 5 6 7 6 9 . 9 1 7 7 0 6 4 . 3 2 2 1 0 9 3 0 5 6 8 6 9 . 3 1 7 7 0 6 4 . 3 2 2 1 0 9 3 0 5 6 9 6 8 . 7 1 7 7 0 6 4 . 4 2 2 1 0 9 3 0 5 7 0 6 8 . 1 1 7 7 0 6 4 . 4 2 2 1 0 9 3 0 5 71 6 7 . 5 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 2 6 6 . 9 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 3 6 6 . 3 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 4 6 5 . 7 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 5 6 5 . 1 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 6 . 6 4 . 5 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 7 6 3 . 9 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 7 8 6 3 . 3 1 7 7 0 6 4 . 5 2 2 1 0 9 3 0 5 69. APPENDIX TABLE I I : F l o c k p r o d u c t i o n d a t a -for t h e H y - l i n e W-77 commercial l a y i n g c h i c k e n . AGE WEEKS 7. H/D PROD BODY WT GMS EGG WT GRAMS TEMP AVE FEED /DAY KCAL /DAY 21 10 14 6 0 2 2 89 25 1 2 2 2 7 15 0 0 4 9 . 6 2 2 9 3 2 6 2 2 3 5 5 1 5 4 0 5 0 . 3 2 2 9 5 2 6 8 2 4 74 15 8 0 5 0 . 8 2 2 9 5 2 6 8 2 5 8 3 1 6 2 0 5 1 . 7 2 2 9 8 2 7 7 2 6 8 7 1 6 6 0 5 2 . 4 2 2 9 8 2 7 7 2 7 8 9 1 6 8 0 5 3 . 4 2 2 100 2 B 2 2 8 9 0 1 7 0 0 5 4 . 6 2 2 101 2 8 5 2 9 9 0 17 1 0 5 5 . 8 2 2 103 291 3 0 9 0 1710 5 6 . 7 2 2 103 2 9 1 31 8 9 1 7 2 0 5 7 . 4 22 104 2 9 3 3 2 8 8 17 2 0 5 8 . 1 2 2 104 2 9 3 3 3 8 8 1 7 3 0 5 8 . 4 2 2 105 2 9 6 3 4 8 7 17 3 0 5 8 . 6 22 105 2 9 6 3 5 8 7 17 4 0 5 9 . 1 2 2 106 2 9 9 3 6 8 6 1 7 4 0 5 9 . 3 2 2 106 2 9 9 3 7 8 5 1 7 5 0 5 9 . 5 2 2 106 2 9 9 3 8 84 17 5 0 6 0 . 0 2 2 106 2 9 9 3 9 8 3 1 7 6 0 6 0 . 2 2 2 106 2 9 9 4 0 8 2 17 6 0 6 0 . 2 2 2 106 2 9 9 41 8 2 1 7 6 0 6 0 . 5 2 2 106 2 9 9 4 2 81 1770 6 0 . 5 2 2 106 2 9 9 4 3 8 0 17 7 0 6 0 . 7 2 2 106 2 9 9 4 4 BO 17 7 0 6 1 . 0 2 2 106 2 9 9 4 5 79 1770 6 1 . 2 2 2 106 2 9 9 4 6 7 9 1 7 7 0 6 1 . 4 2 2 106 2 9 9 4 7 7 8 17 8 0 6 1 . 4 2 2 106 2 9 9 4 8 7 7 1 7 8 0 6 1 . 7 22 106 2 9 9 4 9 7 6 1 7 8 0 6 1 . 7 22 106 299 5 0 7 6 1 7 8 0 6 1 . 9 2 2 106 2 9 9 51 7 5 1 7 8 0 6 1 . 9 2 2 106 2 9 9 5 2 74 17 8 0 6 2 . 1 22 106 2 9 9 5 3 7 3 1 7 9 0 6 2 . 4 2 2 106 2 9 9 5 4 7 3 1 7 9 0 6 2 . 6 2 2 106 2 9 9 5 5 7 2 17 9 0 6 2 . 6 2 2 106 2 9 9 5 6 7 2 17 9 0 6 2 . 8 2 2 106 2 9 9 5 7 71 1 7 9 0 6 3 . 1 2 2 106 2 9 9 5 8 7 0 1800 6 3 . 3 2 2 106 2 9 9 5 9 6 9 1 8 0 0 6 3 . 3 2 2 106 2 9 9 6 0 6 8 18 0 0 6 3 . 6 2 2 106 2 9 9 61 6 7 1 8 0 0 6 3 . 6 2 2 106 2 9 9 6 2 6 7 1 B 0 0 6 3 . 8 22 106 2 9 9 6 3 6 6 1 8 0 0 6 3 . 8 2 2 106 2 9 9 6 4 6 5 1 8 1 0 6 4 . 0 2 2 106 2 9 9 6 5 6 5 1 B 1 0 6 4 . 0 2 2 106 2 9 9 6 6 6 4 18 1 0 6 4 . 3 2 2 106 2 9 9 6 7 6 3 1 8 1 0 6 4 . 3 2 2 106 2 9 9 6 8 6 3 1 8 1 0 6 4 . 5 2 2 106 299 6 9 6 2 1 8 1 0 6 4 . 5 2 2 106 2 9 9 70 61 1 B10 6 4 . 7 22 106 2 9 9 71 6 0 1810 6 5 . 0 2 2 106 2 9 9 7 2 6 0 18 1 0 6 5 . 0 2 2 106 2 9 9 7 3 5 9 1 8 1 0 6 5 . 0 2 2 106 2 9 9 7 4 5 9 1 8 1 0 6 5 . 0 2 2 106 2 9 9 7 5 5 8 1 8 1 0 6 5 . 2 2 2 106 2 9 9 7 6 5 8 l B l O 6 5 . 2 2 2 106 2 9 9 7 7 5 7 1 8 1 0 6 5 . 4 2 2 106 2 9 9 7 8 5 7 1 8 1 0 6 5 . 4 2 2 106 2 9 9 7 9 5 6 1 8 1 0 6 5 . 7 2 2 106 2 9 9 8 0 5 5 1 8 1 0 6 5 . 7 2 2 106 2 9 9 APPENDIX TABLE I I I : Combined -flock p r o d u c t i o n d a t a -for t h e Dekalb X L - L i n k and H y - l i n e W-77 commercial l a y i n g c h i c k e n s . AGE V. H/D BODY EGG AMBIENT F E E D KCAL WEEKS PROD WT GMS WT GMS TEMP /DAY /DAY 2 0 2 1 3 0 0 4 5 2 2 7 5 211 21 10 141B 4 6 2 2 8 3 2 3 2 2 2 2 9 1 4 7 0 4 8 2 2 8 9 2 5 0 2 3 5 3 1 5 2 0 5 0 2 2 9 4 2 6 4 2 4 7 2 1 5 6 0 5 0 2 2 9 8 2 7 4 2 3 84 1 5 9 3 5 2 2 2 1 0 0 2 8 0 2 6 8 8 1 6 2 3 5 2 2 2 100 281 2 7 9 0 1 6 4 5 5 4 2 2 102 2 8 7 2 8 91 1 6 6 5 5 5 2 2 104 291 2 9 91 1 6 7 8 5 6 2 2 105 2 9 5 3 0 91 1 6 8 5 5 7 2 2 106 2 9 7 31 9 0 169B 5 7 2 2 106 2 9 8 3 2 8 9 1 7 0 3 5 8 2 2 106 2 9 8 3 3 8 9 1 7 1 5 5 8 2 2 107 2 9 9 3 4 B8 1 7 2 0 5 9 2 2 107 2 9 9 3 5 8 8 17 3 0 5 9 2 2 107 301 3 6 8 7 1 7 3 3 5 9 2 2 107 3 0 1 3 7 8 6 1 7 4 0 6 0 2 2 107 301 3 8 8 6 1 7 4 3 6 0 2 2 107 301 3 9 8 5 1 7 5 0 6 0 2 2 107 3 0 1 4 0 84 1 7 5 3 61 2 2 107 3 0 1 41 84 1 7 5 8 61 2 2 107 301 4 2 8 3 1 7 6 3 6 1 2 2 107 3 0 1 4 3 8 2 1 7 6 3 61 2 2 107 301 4 4 8 2 1 7 6 3 61 2 2 108 3 0 2 4 5 81 1 7 6 3 6 2 2 2 108 3 0 2 4 6 81 1 7 6 8 6 2 2 2 108 3 0 2 4 7 BO 17 7 3 6 2 2 2 108 3 0 2 48 7 9 1 7 7 3 6 2 2 2 108 3 0 2 4 9 7 8 1 7 7 3 6 2 2 2 10B 3 0 2 5 0 7B 1 7 7 3 6 2 2 2 10B 3 0 2 51 7 7 1 7 7 5 6 2 2 2 10B 3 0 2 5 2 7 6 1 7 7 5 6 3 22 108 3 0 2 5 3 7 6 17 8 0 6 3 2 2 108 3 0 2 5 4 7 5 1 7 B 0 6 3 2 2 108 3 0 2 5 5 7 5 17 8 0 6 3 2 2 108 3 0 2 5 6 74 17 8 0 6 3 2 2 108 3 0 2 57 7 3 1 7 8 0 6 3 2 2 10B 3 0 2 5 8 7 3 1 7 8 5 6 4 2 2 10B 3 0 2 5 9 7 2 1 7 8 5 64 2 2 108 3 0 2 6 0 71 1 7 8 5 6 4 2 2 108 3 0 2 61 7 0 1 7 8 5 64 2 2 l O B 3 0 2 6 2 7 0 1 7 8 5 64 2 2 108 3 0 2 6 3 6 9 1 7 8 5 64 2 2 108 3 0 2 64 6 B 1 7 9 0 6 4 2 2 l O B 3 0 2 6 5 6 8 1 7 9 0 64 2 2 108 3 0 2 6 6 6 7 1 7 9 0 6 4 2 2 108 3 0 2 6 7 6 6 1 7 9 0 6 4 2 2 108 3 0 2 6 8 6 6 1 7 9 0 6 4 2 2 108 3 0 2 6 9 6 5 1 7 9 0 6 4 2 2 108 3 0 2 7 0 6 5 1 7 9 0 6 5 2 2 108 3 0 2 71 6 4 1 7 9 0 6 5 2 2 108 3 0 2 7 2 6 3 1 7 9 0 6 5 2 2 108 3 0 2 7 3 6 3 1 7 9 0 6 5 2 2 1 0 8 3 0 2 7 4 6 2 1 7 9 0 6 5 2 2 l O B 3 0 2 7 5 6 2 1 7 9 0 6 5 2 2 108 3 0 2 7 6 61 1 7 9 0 6 5 2 2 108 3 0 2 7 7 6 0 1 7 9 0 6 5 2 2 108 3 0 2 7 8 6 0 1 7 9 0 6 5 2 2 108 3 0 2 APPENDIX TABLE IV: P r o d u c t i o n d a t a f o r e x p e r i m e n t a l f l o c k L82-PF6. 28 DAY 7. H/D BODY PERIOD PROD WT GMS 1 84.83 1491 2 86.18 1530 .3 B4.30 1539 4 82.09 1560 5 81.49 1610 6 75.71 1631 7 78.07 1670 8 75.04 1659 9 73.71 1659 10 66.43 1659 11 59.53 1670 12 58.12 1690 EGG WT TEMP ME INTAKE GRAMS AVE C OBSERVED 50.29 27.1 252.2 53.54 27.7 254.5 55.54 25.7 255.4 56.18 24.5 267.8 57.81 19.3 287.3 59.52 16.4 309.9 60.14 18.2 314.4 60.97 20.1 302.3 60.79 20.1 287.8 60.10 20.4 272.5 60.29 21.2 278.7 61.15 22.2 281.2 APPENDIX TABLE V: P r o d u c t i o n d a t a f o r e x p e r i m e n t a l f l o c k L82-PF17. 28 DAY 7. H/D BODY EGG WT TEMP ME INTAKE PERIOD PROD WT GMS GRAMS AVE C OBSERVED 1 88.86 2 90.58 3 87.91 4 87.21 5 85.77 6 84.84 7 83.80 8 81.23 9 80.58 10 78.57 11 76.98 12 73.15 1502 52.08 1565 56.37 1595 60.22 1634 60.54 1665 61.15 1676 62.33 1709 62.47 1735 63.94 1728 63.96 1765 64.12 1779 64.26 1785 63.70 25.6 265.3 24.0 274.4 22.4 292.4 21.2 304.4 21.1 302.6 21.4 314.2 23.7 322.9 24.3 306.6 24.3 319.3 24.9 322.6 26.2 319.7 28.6 295.3 APPENDIX TABLE V I : P r o d u c t i o n d a t a f o r e x p e r i m e n t a l f l o c k L76-G41. 28 DAY % H/D BODY EGG WT TEMP ME INTAKE PERIOD PROD WT GMS GRAMS AVE C OBSERVED 1 73.53 1411 50.71 21.1 252.2 2 87.70 1451 52.89 17.2 284.0 3 85.60 1533 55.52 15.0 304.5 4 82.20 1601 57.27 10.0 297.3 5 78.80 1656 58.16 7.8 329.7 6 75.50 1715 59.33 7.2 332.5 7 73.57 1687 60.30 14.4 299.2 8 70.90 1710 60.92 16.7 307.5 9 69.23 1724 61.73 20.6 289.5 10 67.23 1733 62.02 23.3 291.5 11 64.33 1719 62.28 26.1 282.3 12 60.60 1706 61.94 23.9 268.0 

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