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Energy and protein requirements of ewes, and the use of non-protein nitrogen [sic] by ewes and early… Naseem, Muhammad Zafarullah 1970

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ENERGY AND PROTEIN REQUIREMENTS OF EWES AND THE USE OF NON-PROTEIN NITROBEN BY EWES AND EARLY WEANED LAMBS  tar  MUHAMMAD ZAFARULLAH NASEEM M.Sc», West Pakistan Agricultural University, 1966  A THESIS SUBMITTED IN PARTIAL FULFIIMENT OF THE REQUIREMENTS FOR THE DEGREE OF M.SC.  i n the Department of Animal Science  We accept this thesis as conforming to the required standard  THE UNIVERSITY OF BRITISH COLUMBIA April, 1970  In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree tha  permission for extensive copying of this thesis  for scholarly purposes may be granted by the Head of my Department or by his representatives.  It is understood that copying or publication  of this thesis for financial gain shall not be allowed without my written permission.  Department The University of British Columbia Vancouver 8, Canada  ABSTRACT  In order to i n v e s t i g a t e the n u t r i t i o n a l requirements l a t e pregnancy and  early  lactation,  two groups of ewes were g i v e n 90  D i g e s t i b l e Crude P r o t e i n (D.C.P.) d u r i n g pregnancy and head/day d u r i n g e a r l y  lactation.  During  the l a s t  ewes i n Group I I , p r o v i d e d w i t h maintenance +  225  D.C.P./  100%, requirement  f e d maintenance + 50%, D.E.  ewes i n Group I, p r o v i d e d w i t h maintenance +  gms.  gms.  - s i x . weeks of pregnancy  Energy (D.E.) made s i g n i f i c a n t l y g r e a t e r l i v e w e i g h t g a i n s those i n Group I and  of ewes d u r i n g  (P<0.01) than  During e a r l y  150%, D.E.  of Digestible  lost  lactation  significantly  l e s s weight (P<0.05) than those i n Group I I which were g i v e n maintenance +  100%, D.E.  There were no  c o m p o s i t i o n between the two Group I was  s i g n i f i c a n t d i f f e r e n c e s i n m i l k y i e l d and groups,  however pre-weaning lamb growth i n  s i g n i f i c a n t l y g r e a t e r (P<0.05) than t h a t i n Group I I .  d a i l y g a i n of weaned lambs (weaned a t 8 to 10 weeks of age) r a t i o n s c o n t a i n i n g 20%, p r o t e i n was  Average  given p e l l e t e d  s i g n i f i c a n t l y g r e a t e r (P<0.05) than  those g i v e n 16%, p r o t e i n but t h e r e were no  s i g n i f i c a n t d i f f e r e n c e s between  lambs f e d 20% or 13% and between 167<, or 13%, crude p r o t e i n .  A higher  p r o p o r t i o n o f s i n g l e lambs i n the group g i v e n 137.. p r o t e i n may i n p a r t f o r the b e t t e r g a i n of t h i s group.  have  accounted  R e s u l t s of the d i g e s t i o n  w i t h these lambs i n d i c a t e d t h a t t h e r e were no (P<0.05) i n the dry matter  milk  d i g e s t i b i l i t y and  significant  trial  differences  the p r o t e i n d i g e s t i o n  of the t h r e e types of p e l l e t s but the n i t r o g e n r e t e n t i o n was  coefficient  g r e a t e s t i n the  lambs f e d the 20%, p r o t e i n . The  r e s u l t s of the second  experiment  conducted,  to study the e f f e c t of  n o n - p r o t e i n n i t r o g e n i n the form of urea on m i l k y i e l d and m i l k o f ewes i n d i c a t e d  t h a t there were no  composition  s i g n i f i c a n t differences i n milk y i e l d ,  m i l k c o m p o s i t i o n and m i l k urea N l e v e l of the t h r e e groups of ewes f e d equal  amounts o f supplemental n i t r o g e n , d u r i n g e a r l y soybean + u r e a and u r e a a l o n e . significantly supplemented  l a c t a t i o n , as soybean,  Ewes f e d soybean  or soybean + urea had  lower plasma urea n i t r o g e n l e v e l s (P<0.05) than those with urea alone.  There was no s i g n i f i c a n t d i f f e r e n c e between  the plasma urea n i t r o g e n l e v e l o f the former  two groups o f ewes.  were no s i g n i f i c a n t d i f f e r e n c e s i n the pre-weaning  There  growth o f lambs n u r s i n g  ewes f e d on p e l l e t s c o n t a i n i n g soybean + urea and u r e a a l o n e b u t the lambs from ewes f e d soybean made s i g n i f i c a n t l y from the o t h e r two groups. difficult  .The r e a s o n f o r t h i s slower r a t e o f g a i n i s  to e x p l a i n .  R e s u l t s o f the t r i a l in  slower (P<0.05) g a i n than those  conducted  to i n v e s t i g a t e the use o f urea n i t r o g e n  e a r l y weaned lambs i n d i c a t e d t h a t the lambs f e d on p e l l e t s c o n t a i n i n g  soybean made s i g n i f i c a n t l y g r e a t e r g a i n s (P<0.05) than those on p e l l e t s c o n t a i n i n g u r e a as the s o l e source o f supplemental n i t r o g e n . however, no s i g n i f i c a n t d i f f e r e n c e s i n weight containing alone.  There were  g a i n o f lambs f e d on p e l l e t s  soybean or soybean + u r e a and between soybean + u r e a or u r e a  There were no s i g n i f i c a n t d i f f e r e n c e s between plasma u r e a n i t r o g e n  l e v e l o f lambs f e d on soybean  or soybean + urea c o n t a i n i n g p e l l e t s and  these lambs had s i g n i f i c a n t l y h i g h e r (P<0.05) l e v e l s o f plasma u r e a n i t r o g e n than those f e d on p e l l e t s c o n t a i n i n g urea a l o n e . u r e a l e v e l o f the lambs was thought  The v a r i a t i o n i n the b l o o d  t o be due to v a r i a t i o n i n p r o t e i n  intake.  R e s u l t s o f the d i g e s t i o n t r i a l w i t h lambs showed t h a t t h e r e were no s i g n i f i c a n t d i f f e r e n c e s i n the p r o t e i n d i g e s t i o n c o e f f i c i e n t s and d r y matter d i g e s t i b i l i t i e s o f these types o f r a t i o n s . soybean  P e l l e t s p r o v i d i n g n i t r o g e n from  resulted i n greatest nitrogen retention.  R e s u l t s show t h a t u r e a d i d n o t i n f l u e n c e the m i l k y i e l d or m i l k c o m p o s i t i o n o f the.ewes but i t was a poor weaned lambs.  source o f n i t r o g e n f o r e a r l y  TABLE OF CONTENTS PAGE I  Introduction Review of the Literature  II III IV  V ¥1  Ewe Nutrition i n Pregnancy and Early Lactation Early Weaning and Feeding of Lambs Urea - Nutritional Importance as a Non-Protein Nitrogen Source  1 3 3 17  23  Effect of Feed Urea on Milk Yield and Milk Composition  37  Experimental  46  Experiment No. I Animals. Used  46  Feeding  4.6  Energy Levels and Feed Supply  47  Milking of Ewes and Analysis of Milk Samples  A8  Weaning of Iambs  49  Digestibility study  49  Experiment No. II Management  51  Milk Yield  51  Blood Analysis  52  Growth of Lambs  53  Digestion T r i a l  53  TABLE OF CONTENTS (Continued) Page VTI  VIII IX  Results and Discussion  54  Experiment I  54  Experiment II  69  Literature Cited Appendices  87 ^  2  LIST OF TABLES Experiment I Table  Page Average Weight of Ewes  57  Ewes Average Daily Milk Yield  58  Single Lamb Growth (Pre-weaning)  59  IV  Twin Lamb Growth (Pre-weaning)  59  V  Average f a t Percentage of Milk  60  VI  Average Protein Percentage of Milk  60  VII  Average Lactose Percentage of Milk  60-A  Post-weaning Lamb Growth  63  Feed Efficiency Ratio  66  Digestion T r i a l of Lambs Dry Matter. Digestibility  67  Digestion T r i a l of Lambs Nitrogen Digested and Retained  68  XII  Ewes Average Daily Milk Yield  71  XIII  Average Fat Percentage of Milk  72  XIV  Average Protein Percentage of Milk  73  XV  Average Lactose Percentage of Milk  73-A  Average Total Solids Percentage of Milk  74.  Ewes Average Milk Urea N  75  Ewes Average Plasma Urea N  77  Lamb Growth (Pre-weaning)  78  Lamb Growth Rate (Post-weaning)  81  Lambs Average Plasma Urea N  82  Digestion T r i a l of Lambs - Dry Matter Digestibility  83  Digestion T r i a l of Lambs - Nitrogen Digested and Retained  84.  I II III  VIII IX X XI Experiment II Table  XVI XVII XVIII XIX XX XXI XXII XXIII  ACKNOWLEDGMENTS  The w r i t e r wishes t o thank Dr. M. T a i t  f o r h i s encouragement and  guidance throughout the course o f t h i s s t u d y . S i n c e r e thanks a r e a l s o extended t o Mr. T. Choa o f t h e P r o v i n c i a l Government D a i r y Branch L a b o r a t o r y f o r a n a l y z i n g m i l k samples. F u r t h e r thanks a r e extended t o Dr. W. D. K i t t s , Chairman Department t h i s study.  of the  o f Animal S c i e n c e , f o r t h e use o f n e c e s s a r y f a c i l i t i e s f o r  1. I.  The  INTRODUCTION  s h o r t i n t e r v a l . f r o m weaning to mating i n sheep p r o d u c t i o n  involving  twice y e a r l y lambing or three  lamb crops  i n twenty f o u r months  necessitates the r e a p p r a i s a l of the n u t r i e n t requirements of ewes. it  i s considered  high-energy feeds lambs p r o d u c t i o n body weight by for p r i o r  t h a t moderate f e e d i n g d u r i n g  and  economy.  l a t e pregnancy f o l l o w e d  the ewe  during  lactation.  T h i s being  accepted  l e v e l than normal d u r i n g  a c c e p t i n g body weight l o s s i n e a r l y l a c t a t i o n .  The  late  to m a i n t a i n  body c o n d i t i o n .  gestation  a l t e r n a t i v e Is to meet  This thesis presents  so d e s i g n e d t h a t one  as p o s s i b l e f o r l a c t a t i o n . of energy d u r i n g  The  feeding  the f i n d i n g s of  group of ewes r e c e i v e d energy  second group r e c e i v e d the  l a t e pregnancy and  be  pregnancy) and  p r o t e i n to meet the requirements of l a t e pregnancy and  the two  compensated  p r o t e i n requirements i n e a r l y l a c t a t i o n by h i g h g r a i n  an experiment which was and  and  I t i s proposed t h a t good body c o n d i t i o n may  ( i n excess of the ewes r e q u i r e m e n t s f o r maintenance and  i n order  by  Such a system u s u a l l y i n v o l v e s a l o s s of  feeding at a higher  the energy and  Normally  i n e a r l y l a c t a t i o n g i v e s the b e s t r e s u l t s i n terms of  to r e b r e e d i n g .  a t t a i n e d by  systems  e a r l y l a c t a t i o n but  then as c l o s e l y same t o t a l amount  evenly  d i v i d e d over  periods.  Since  the  lambs may  have to be weaned e a r l y i n i n t e n s i v e  production  systems, the p r o t e i n requirements of e a r l y weaned lambs were a l s o  investi-  gated. There i s evidence t h a t u r e a n i t r o g e n can be u t i l i z e d by d a i r y cow  without detrimental  Comparable work w i t h  sheep has  e f f e c t s on m i l k y i e l d and not been c a r r i e d o u t .  f u r t h e r experiment a r e p r e s e n t e d  which was  The  the  lactating  composition. r e s u l t s of a  conducted to study the  effect  of urea n i t r o g e n on m i l k y i e l d and m i l k c o m p o s i t i o n o f ewes.  Three  groups  o f ewes were p r o v i d e d e q u a l amounts o f supplemental n i t r o g e n , d u r i n g e a r l y lactation,  from  and u r e a a l o n e .  t h r e e d i f f e r e n t r a t i o n s c o n t a i n i n g soybean, soybean + u r e a The use o f urea n i t r o g e n i n e a r l y weaned lambs was a l s o  i n v e s t i g a t e d by f e e d i n g the above-mentioned r a t i o n s f o r 16 weeks to weaning a t e i g h t weeks o f age.  subsequent  3. REVIEW OF LITERATURE II'.  EWE NUTRITION I N PREGNANCY AND EARLY LACTATION  Considerable  i m p o r t a n c e h a s b e e n a t t a c h e d t o t h e f l u s h i n g o f ewes  b e f o r e m a t i n g a n d t h i s h a s become common p r a c t i c e i n many c o u n t r i e s . Flushing has a s i g n i f i c a n t e f f e c t a n d h e n c e t h e number  o n i n c r e a s i n g t h e number  o f lambs p r o d u c e d ( C o o p ,  o f eggs  1966) b u t t h e r e a r e o t h e r  p e r i o d s when t h e n u t r i t i o n a l s t a t u s o f t h e ewe i s i m p o r t a n t . p e r i o d o f t h e ewe i s n e a r l y foetal weight foetus for  increase i s small.  for nutriment  the ewe.  21 w e e k s ,  As there  at this time,  De C l e e n e  (1968)  during  the f i r s t  is little  stated that  t h e n u t r i t i o n o f t h e ewe i s i m p o r t a n t  a heavier  10 w e e k s o f  extra  This  pregnancy  demand f r o m t h e  i n t h e l a s t f o u r weeks It  i s during  c o u l d r e s u l t i n an a l r e a d y  before  t h i s month  because i t can a f f e c t  R a i s i n g the ewe's plane of n u t r i t i o n to a h i g h lamb a t b i r t h .  The g e s t a t i o n  only a maintenance r a t i o n i s r e q u i r e d  lambing the foetus n e a r l y doubles i t s w e i g h t .  lamb b o r n .  shed  that  the s i z e of the l e v e l w o u l d mean  large  unborn  single  lamb i n i n c r e a s i n g i t s b i r t h w e i g h t b y a n e x t r a p o u n d .  weight  c o u l d make t h e d i f f e r e n c e b e t w e e n a n e a s y a n d a d i f f i c u l t b i r t h a n d  therefore  affect  total  ewe t o a l o w f e e d i n g  lamb l o s s e s .  l e v e l during  He f u r t h e r  l a t e pregnancy,  s h o u l d be a v o i d e d ,  a s t h i s w o u l d mean t h a t  lighter  A small  at birth.  subsequently d i e .  This  feeding the is  die i n their  l e v e l s a l s o have an e f f e c t  lamb.  Excess  subjecting the  on the other  hand,  also  to fend f o r i t s e l f and  i s particularly relevant  of these w i l l  that  t h e lamb p r o d u c e d w o u l d b e  lamb may b e t o o weak  that although a large proportion of l i g h t g r e a t number  stated  The i n c r e a s e d  to twin lambs.  He s t a t e d  lambs s u r v i v e p a r t u r i t i o n ,  f i r s t week.  a  He p o i n t e d o u t t h a t  o n t h e ewe i n a d d i t i o n t o t h e e f f e c t o n  feeding during early pregnancy,  when v e r y  little  demand  b e i n g made b y t h e f o e t u s o n t h e e w e , r e s u l t s i n a b u i l d u p o f e x c e s s  body  fat.  This  i n turn  lowers  the a n i m a l ' s general f i t n e s s .  He s a i d  that  difficulty higher further  a t p a r t u r i t i o n i s p a r t l y a h e r i t a b l e t r a i t b u t the i n c i d e n c e i s  i n animals c a r r y i n g too much c o n d i t i o n when approaching lambing. s t a t e d t h a t pregnancy toxaemia i s a c o n s t a n t  g e s t a t i o n when demands on the ewe a r e r e a c h i n g c a r b o h y d r a t e the ewe r e q u i r e s intake,  i s greater  (acetone, a c e t o a c e t i c rumen e p i t h e l i u m toxaemia.  As a r e s u l t t o x i n s  and mammary gland which may cause ewe's death from pregnancy to keep the ewes on maintenance  e a r l y and mid-pregnancy w i t h a g r a d u a l l y  During e a r l y pregnancy ewes should  r i s i n g p l a n e of  lambing. be f e d to m a i n t a i n a c o n s t a n t  Coop (1962) s t a t e d t h a t under c o n f i n e d  enclosures)  feed  a c i d and B - h y d r o x y b u t y r i c a c i d ) a r e produced i n l i v e r ,  n u t r i t i o n over the l a s t few:.weeks b e f o r e  weight.  I f the amount o f  than t h a t a v a i l a b l e through  He concluded t h a t i t i s important  r a t i o n s during  t h r e a t near the end of  a peak.  then body f a t r e s e r v e s w i l l be c a t a b o l i z e d .  He  a 45 kg. (100 l b . ) sheep r e q u i r e s  conditions  body  (4ft. x 6ft.  0.96 l b . T.D.N. ( 1 9 2 0 & c a l o r i e s  D.E.) or 0.92 l b . d i g e s t i b l e o r g a n i c matter to m a i n t a i n a c o n s t a n t  body  weight. Langlands, C o r b e t t ,  McDonald and P u l l a r (1963) e s t i m a t e d t h a t the  maintenance requirement o f a 100 l b . housed sheep was 0.82 l b . d i g e s t i b l e o r g a n i c matter. Investigations  i n t o the e f f e c t o f p r o t e i n i n t a k e d u r i n g  the second h a l f  of pregnancy on lamb b i r t h weights and ewe m i l k y i e l d d u r i n g  early lactation  have g i v e n v a r i a b l e r e s u l t s . during  S l e n and W h i t i n g  (1952) f e d ewes i n d i v i d u a l l y  l a t e g e s t a t i o n and e a r l y l a c t a t i o n , r a t i o n s c o n t a i n i n g  t o t a l p r o t e i n (3.3, 6.3 and 8.1% d i g e s t i b l e crude p r o t e i n )  7,  10 and 137,,  to study the  i n f l u e n c e o f p r o t e i n i n t a k e on body weight o f ewes and b i r t h weight and growth of the lambs.  Average d a i l y  intakes  t o t a l d i g e s t i b l e n u t r i e n t s f o r the three  of d i g e s t i b l e crude p r o t e i n and  l e v e l s of p r o t e i n during  late  5 .  g gestation and  and  l a c t a t i o n were 0 . 1 3  early  l b . D.C.P. ( d i g e s t i b l e crude p r o t e i n )  1 . 7 l b . T.D.N, ( t o t a l d i g e s t i b l e n u t r i e n t s ) ; 0 . 2 3 0.29  T.D.N.; and receiving  low  1 . 9 l b . T.D.N.  l b . D.C.P. and (77»)  protein  r a t i o n d i d not  R e s u l t s showed that  g a i n as r a p i d l y as  r e c e i v i n g h i g h e r l e v e l s but  t h e r e was  1 0 7 o and  Average body weights of the  137o total protein.  lamb i n g were 1 5 4 , 171  l b . ; and  160  ewes r e c e i v i n g  low  Many of  the  of d i g e s t i b l e crude p r o t e i n produce a v i g o r o u s lamb or  of no  lambs and  protein  the  I t was  the  fed  the  the  signifi-  two  to ewes r e c e i v i n g  low  higher the  these  p r o t e i n r a t i o n were  lamb and  d a i l y d u r i n g pregnancy was  no m i l k  none had  and  sufficient  not  singles  and  lamb and  lamb b i r t h weights between i n t a k e s However ewe  the  two  higher  higher  and  mortality  l e v e l s of  s u f f i c i e n t for  Dinusson  found no  of 0 . 1 0  two  lambs. protein  a t weaning time than lambs r a i s e d  many had  ewes of about 1 2 0 l b . l i v e weight and  i n the  lb.  s u f f i c i e n t to  s u f f i c i e n t to produce m i l k f o r n u r s i n g  Klosterman, B o l i n , Buchanan, B o l i n and  daily.  There were no  than  e v i d e n t from t h i s experiment t h a t 0 . 1 3  A l l ewes r e c e i v i n g  s u f f i c i e n t m i l k f o r one  ewe  1 6 8 and  twin lambs from  2 4 lambing i n t h i s group had  twin lambs r a i s e d as  p r o t e i n groups.  per  160,  a d d i t i o n a l value i n increasing  groups were h e a v i e r a t s i x weeks of age  protein  receiving  1 5 2 l b . f o r 7 , 1 0 and  and  ration.  i n s u f f i c i e n t m i l k to nurse one  m i l k to r a i s e twin lambs.  had  groups  ewes 6 weeks b e f o r e  lambs from ewes r e c e i v i n g  lambs from the ewes on  weak a t b i r t h , t h r e e ewes of  i n low  two  between groups  s i n g l e and  protein  i n d i c a t i n g that e x t r a  h i g h e s t l e v e l of p r o t e i n was  single  the  i n b i r t h weights of  l e v e l s of p r o t e i n  The  Both the  150  the  the ewes  the h i g h e r l e v e l s of p r o t e i n were s i g n i f i c a n t l y h e a v i e r  cant d i f f e r e n c e s  another s i x had  lambing, 1 3 5 ,  respectively.  lambs from ewes r e c e i v i n g  weights.  difference  1 6 0 l b . ; 2 weeks b e f o r e lambing,  immediately a f t e r  137o t o t a l protein,  the  and  no  1 . 9 lb.  l b . D.C.P. and  ( 1 9 5 3 )  protein  twins. experimented w i t h  significant differences 0.28 was  in  l b . d i g e s t i b l e crude  h i g h e r on  the  lower  protein  i n t a k e and m i l k y i e l d as a s s e s s e d adversely  should  lambs was a l s o  affected.  Phillipson day  by the growth o f twin  (1959) concluded  t h a t 0.25 l b . d i g e s t i b l e crude p r o t e i n per  be adequate f o r the 140 l b . ewe d u r i n g  the l a s t  s i x weeks o f  gestation. (1968) recommended 0.20 l b . d i g e s t i b l e crude  N a t i o n a l Research C o u n c i l p r o t e i n per day d u r i n g  s i x weeks o f g e s t a t i o n f o r a ewe o f 140 l b .  the l a s t  l i v e weight or more. Gardner and Hogue (1963) experimented w i t h  ewes to determine the T.D.N,  ( t o t a l d i g e s t i b l e n u t r i e n t s ) r e q u i r e m e n t s o f pregnant and l a c t a t i n g ewes. The  l e v e l " of T.D.N, used was t h a t recommended by N a t i o n a l Research  (1957) f o r 130 l b . ewes d u r i n g per  100 lb.bd)%iwe^h'tr3)& i n<  f°  rt  the l a s t 6 weeks o f g e s t a t i o n (1.77 l b . T.D.N, n  8 t o 10 weeks o f l a c t a t i o n (2.3 l b .  e first  T.D.N, per 100 l b . body w e i g h t ) .  The l e v e l of T.D.N, t e s t e d was as above  or 75, 100 or 1257o o f those v a l u e s The  Council  before  or a f t e r lambing o r throughout.  l e v e l o f p r o t e i n used was the same as t h a t o f N.R.C. (0.23 l b . d i g e s t i b l e  crude p r o t e i n d u r i n g  last  s i x weeks of g e s t a t i o n and 0.3 l b . d u r i n g  lactation)  T h e i r r e s u l t s showed t h a t v a r y i n g  T.D.N, l e v e l s f o r ewes d u r i n g  weeks o f g e s t a t i o n d i d n o t a f f e c t  s i n g l e lamb b i r t h w e i g h t s but f e e d i n g  higher  levels significantly  T.D.N, l e v e l s d u r i n g weight o f twin  increased  twin b i r t h w e i g h t s .  gestation significantly  lambs and f e e d i n g h i g h e r  lambs.  higher  the average 90 day increased  The r e s u l t s a l s o showed  s i n g l e lambs, a p p r o x i m a t e l y m a i n t a i n e d t h e i r body weight from  s i x weeks pre-parturn f e d the p r e s e n t  Feeding  l a c t a t i o n l e v e l s to ewes  the 90 day weights of both s i n g l e and twin t h a t ewes w i t h  increased  the l a s t s i x  to one day post-partum and to 90 day post-partum when  N.R.C. standard  mately the 125% l e v e l .  whereas ewes w i t h  These data  twins r e q u i r e d  approxi-  i n d i c a t e d t h a t the p r e s e n t N.R.C. - T.D.N.  standard was increased  apparently s a t i s f a c t o r y  f o r ewes pregnant w i t h s i n g l e lambs but  l e v e l s f o r ewes pregnant w i t h twin lambs  Wright, Pope, and P h i l l i p s  (1964) s t a t e d  seemed a d v i s a b l e .  that oat straw, maize cobs  and l o w - q u a l i t y hay as roughages each supplemented w i t h m i n e r a l s and g i v e n as p e l l e t s were s a t i s f a c t o r y  f o r pregnant and lactating ewes.  V a r i o u s l e v e l s of feed energy have been i n v e s t i g a t e d d u r i n g pregnancy.  J o r d a n (1966) r e p o r t e d  protein  late  t h a t hay r a t i o n s p r o v i d i n g about 3000 K.  c a l o r i e s and h i g h c o n c e n t r a t e r a t i o n s p r o v i d i n g  1800 K. c a l o r i e s of d i g e s -  t i b l e energy per ewe d a i l y d u r i n g summer, nonpregnant dry p e r i o d of f o u r months r e s u l t e d i n weight l o s s e s o f about 1 and 5 Kg. r e s p e c t i v e l y . changes were s i g n i f i c a n t l y d i f f e r e n t .  During g e s t a t i o n about  3*®i0  Weight and 3930 K.  c a l o r i e s (D.E.) per ewe d a i l y were p r o v i d e d by hay and h i g h c o n c e n t r a t e rations, respectively.  Results indicated  t h a t weight g a i n s were not  s i g n i f i c a n t l y d i f f e r e n t and averaged 18.8 and 16.5 Kg. per ewe, He f u r t h e r  respectively.  s t a t e d t h a t lamb weights taken a t b i r t h and a t 30 days of age  were not a f f e c t e d by the summer and g e s t a t i o n treatments o f t h e i r dams, s u g g e s t i n g t h a t a l l r a t i o n s were s u f f i c i e n t l y adequate to p r o v i d e ample n u t r i e n t s f o r the d e v e l o p i n g f o e t u s and f o r m i l k p r o d u c t i o n . I t has been shown t h a t body weight of ewes markedly, a f f e c t s the weaning weight and to a l e s s e r degree the b i r t h weight of  lambs.  Ray and Smith (1966) a n a l y z e d b i r t h and weaning weight r e c o r d s They d e c l a r e d t h a t age o f dam  (from 2 to 7 y e a r s ) d i d not  a f f e c t weight of lambs a t b i r t h .  Twin ram lambs were 0.59  b i r t h and 1.8 Kg. h e a v i e r a t weaning There was  ofllambs.  significantly Kg. h e a v i e r a t  (120 days o f age) than twin ewe  lambs.  a 5«.63 Kg. i n c r e a s e i n weaning weight, when weaned a t 120 days  of age, w i t h each k i l o g r a m i n c r e a s e i n b i r t h weight.  The g r e a t e s t response  of weaning weight to i n c r e a s e i n b i r t h weight o c c u r r e d i n s i n g l e lambs. body weight o f the ewes markedly a f f e c t e d  the weaning weight and to a  The  lesser  degree the b i r t h weight of lambs. replacement  ewe  They s t a t e d t h a t s e l e c t i o n o f heavy  lambs f o r the b r e e d i n g  f l o c k would be d e s i r a b l e  upon the e x t r a c o s t of f e e d i n g heavy ewes). i n c r e a s e d t h e r e was  59.5  4 1 , ; 4 to 4 5 . 5  Nedkv£<tnena s i l a g e or both last  to 6 3 . 6  Kg.  The and  than ewes i n the l i g h t e s t group  Kg.  ( 1 9 6 7 )  conducted  t r i a l s w i t h ewes f e d i n d o o r s on hay  from b e f o r e mating to 2 to 3 weeks a f t e r  2 or 8 weeks of pregnancy ewes got 0 . 2  to 1 2 7 o d i g e s t i b l e crude p r o t e i n . g i v e n s i l a g e a l o n e or hay w i t h the b i r t h weight of lambs was others.  L  produced lambs t h a t weighed 9 7 o  more a t b i r t h and weaning r e s p e c t i v e l y ,  weighing  the body weight of ewes j. .  a s i g n i f i c a n t i n c r e a s e i n weaning w e i g h t s of lambs.  h e a v i e s t ewes weighing 207o  As  (depending  Kg.  lambing  and  i n the  concentrate d a i l y with 1 1  R e s u l t s of the t r i a l  showed t h a t the ewes  s i l a g e produced most o f f s p r i n g . lower  or  among ewes g i v e n hay  alone  On  the whole  than f o r  Most deaths were among lambs w i t h v e r y low or h i g h b i r t h weight.  Weight g a i n from b i r t h to weaning was  u s u a l l y l e a s t w i t h hay  alone  and  c o n c e n t r a t e s g i v e n f o r 8 i n s t e a d of 2 weeks improved b i r t h weight of o n l y i n the group f e d on hay  alone.  twins  The a d d i t i o n of c o n c e n t r a t e to hay  s i l a g e r e s u l t e d i n f u l f i l m e n t of the p r o t e i n requirements  during  or  late  pregnancy. Pregnant ewes being  fed on p a s t u r e a l o n e should be g i v e n a supplement  d u r i n g l a t e g e s t a t i o n to meet the requirements better milk Pogodin  ( 1 9 6 7 )  Kg.  s t u d i e d the e f f e c t of l e v e l of n u t r i t i o n of pregnant  days of pregnancy f e d on p a s t u r e alone or w i t h a  supple-  b a r l e y meal, on weight changes and m i l k p r o d u c t i o n .  showed t h a t the average l o s s o f weight d u r i n g pregnancy was i n ewes on p a s t u r e a l o n e and out.  for  production.  ewes, d u r i n g 1 5 0 ment of 0 . 5  of l a t e pregnancy and  least,  1 0 . 0 7 o  greatest,  i n those g i v e n b a r l e y meal  Those g i v e n the supplement f o r the l a s t  15.  3 5 , 7 0 or 1 0 0  days  Results 1 7 . 8 7 o  through lost  9.  l e s s weight than those g i v e n i t f o r the c o r r e s p o n d i n g  p e r i o d s at the  Average m i l k y i e l d s d u r i n g 20 days a t the s t a r t of l a c t a t i o n , from t h i r d day  start.  the  a f t e r lambing when the lambs were removed, were s i g n i f i c a n t l y  g r e a t e r i n ewes g i v e n the supplement f o r the l a s t 15 to 100 g i v e n i t o n l y f o r the f i r s t gestation.  50 days and  days  than.those  than those g i v e n no supplement d u r i n g  I t has been shown t h a t lamb b i r t h weights; a r e not a f f e c t e d by  the source of p r o t e i n i n the f e e d of t h e i r dams i f the dams a r e s u p p l i e d w i t h adequate p r o t e i n l e v e l d u r i n g g e s t a t i o n . Forbes and Robinson (1967) s t u d i e d the e f f e c t of source and  level  of d i e t a r y p r o t e i n on the performance of ewes a f t e r 10 weeks of g e s t a t i o n . Grass meal was  used as a s u b s t i t u t e f o r f r e s h grass and. soybean meal r e p r e -  s e n t i n g a more c o n v e n t i o n a l source of p r o t e i n was sources or 0.2  of p r o t e i n were i n c l u d e d a t two lb./day)  crude p r o t e i n .  and a low The  (45 g. or 0.1  26.7  lb./day)  T h i s was  (90  the same.  The  not  dry m a t t e r d i g e s t i b i l i t y was i n g soybean meal and  and  level  e q u i v a l e n t to 100 k. c a l o r i e s of  a f f e c t e d by stage of g e s t a t i o n . 67.7%  g.  kilogram  energy/kg.(wP*^3) /day where W=live weight i n Kg.  matter d i g e s t i b i l i t y was  Both  i n t a k e of d i g e s t i b l e  g. of d i g e s t i b l e o r g a n i c m a t t e r per  m e t a b o l i c weight (W^*73)/day.  ficant.  l e v e l s , providing a high  i n t a k e of d i g e s t i b l e energy was  of f e e d i n g adopted was  metabolizable  compared w i t h i t .  58.2%  The  The  dry  percent  of i n t a k e f o r the d i e t s c o n t a i n -  grass meal, r e s p e c t i v e l y .  The  d i f f e r e n c e s were s i g n i -  Lower dry m a t t e r d i g e s t i b i l i t y i n d i e t s c o n t a i n i n g grass meal  was  ! i  thought to be due  to f i n e m i l l i n g .  a f f e c t e d by source or l e v e l  'Lamb b i r t h weights were not  of d i e t a r y p r o t e i n .  Ewes  significantly  weight gaiiis d u r i n g  10.  the l a s t  8 weeks o f g e s t a t i o n were s i g n i f i c a n t l y a f f e c t e d by  dietary protein.  L i v e weight gains  on h i g h e r p r o t e i n i n t a k e s .  weight l o s s .  Source of p r o t e i n d i d not have a s i g n i f i c a n t The  low n i t r o g e n r e t e n t i o n r a t e  mean l i v e weight g a i n and  growth d u r i n g l a t e g e s t a t i o n .  to m a i n t a i n  G e s t a t i o n treatments had no  performance o f ewes or lambs d u r i n g the f i r s t  was  the h i g h e s t mean net body  T h i s emphasized the c a p a c i t y of the ewe  Robinson and Forbes  of  of the ewes were s i g n i f i c a n t l y b e t t e r  e f f e c t on l i v e weight g a i n of ewes. a s s o c i a t e d w i t h lowest  the l e v e l  foetal  e f f e c t on  t h r e e weeks of  the  lactation.  (1967) c a r r i e d out an experiment i n which p r o t e i n u t i -  l i z a t i o n i n the pregnant ewe  was  s t u d i e d u s i n g the n i t r o g e n b a l a n c e  E i g h t d i e t s s u p p l y i n g f o u r d i f f e r e n t i n t a k e s o f crude p r o t e i n and  technique.  two  differ-  ent i n t a k e s o f energy were each o f f e r e d t o i n d i v i d u a l l y penned ewes. mean crude p r o t e i n i n t a k e s per day were 7.2,5.5, 4.1 (W=body weight i n Kg.)  and  the m e t a b o l i z a b l e  and  3.0  The  g./Kg.W  energy i n t a k e s 134  and  0  73  113  0.73 K.  calories/Kg.W *  to 16 and  18  unit metabolic  and was The  not  N i t r o g e n b a l a n c e was  to 20 weeks of g e s t a t i o n .  advanced t h e r e was  i n t a k e was  .  c a r r i e d out a t 10  T h i s was  14  R e s u l t s showed t h a t as pregnancy  a decrease i n the i n t a k e o f m e t a b o l i z a b l e  body weight.  to 12,  due  energy  mainly to the f a c t t h a t  per  the  based.on the l i v e weights o f ewes a t s i x weeks o f g e s t a t i o n adjusted  decreased  f o r i n c r e a s e i n body weight as pregnancy advanced.  i n t a k e was  more pronounced on the l o w - p r o t e i n  weight o f food l e f t uneaten expressed  diets.  as a percentage of t o t a l  The  food  o f f e r e d i n c r e a s e d from under 1% on a l l d i e t s a t 10 to 12 weeks of g e s t a t i o n to 6.4%  on the h i g h e s t p r o t e i n d i e t and  just before p a r t u r i t i o n .  The  to 1-3.0% on the lowest  intakes of metabolizable  p r o t e i n d i e t s were lower but were adequate.  There was  protein diet  energy w i t h  the low •  a significant  reduction  11.  i n dry matter d i g e s t i b i l i t y with decreasing p r o t e i n i n t a k e . due  to an a s s o c i a t e d d e c r e a s e i n t h e numbers o f rumen b a c t e r i a ! w i t h low  protein diets.  There was a s i g n i f i c a n t l y h i g h e r d r y matter  on t h e h i g h energy d i e t s . t a b l e carbohydrate  creased  i n these d i e t s .  a t a l l stages  fermen-  With t h e h i g h e r energy i n t a k e and h i g h e r  of gestation.  t h e number o f f o e t u s e s  digestibility  T h i s was due t o h i g h e r p r o p o r t i o n o f r e a d i l y  p r o t e i n i n t a k e s the r e t e n t i o n o f n i t r o g e n  by  The d e c r e a s e was  carried.  ( d i g e s t e d ) was s i g n i f i c a n t l y i n -  Retention  o f n i t r o g e n was n o t a f f e c t e d  The mean l e v e l s o f n i t r o g e n r e t a i n e d on  0.73 the h i g h and low energy d i e t s were 0.142 and 0.100 g./Kg.'W " respectively. The mean i n c r e a s e i n r e t e n t i o n o f d i g e s t e d n i t r o g e n p e r K. c a l o r i e i n metabolizable  increase  energy i n t a k e was 2 mg. and v a r i e d from 1.3 mg. a t 10 to  12 weeks o f g e s t a t i o n t o 2.5 mg. j u s t b e f o r e p a r t u r i t i o n . the importance o f energy i n t a k e on n i t r o g e n u t i l i z a t i o n . energy i n t a k e s h i g h e r  than -the g e n e r a l l y accepted  This  emphasized  They suggested t h a t  requirement o f maintenance  p l u s 25% f o r l a t e pregnancy may have a b e n e f i c i a l e f f e c t on n i t r o g e n r e t e n t i o n . The  l e v e l s o f n i t r o g e n r e t a i n e d a t mid pregnancy on i n t a k e s o f 0.50 and 0.15  g. d i g e s t e d nitrogen/Kg.W^*73 p  e r  day were s i m i l a r t o those o b t a i n e d  pregnant ewes on comparable i n t a k e s .  f o r non  T h i s i n d i c a t e d t h a t up t o mid pregnancy  the demand f o r n i t r o g e n i s s i m i l a r to t h a t o f non pregnant a n i m a l s .  Nitrogen  r e t e n t i o n i n c r e a s e d w i t h advancing pregnancy and the r e t e n t i o n s a t 10 t o 12, 14. t o 16 and 18 t o 20 weeks o f g e s t a t i o n were 0.086, 0.114 and 0.163 g./Kg. 0.73 W "  ' p e r day, r e s p e c t i v e l y .  panied by a c o r r e s p o n d i n g  The i n c r e a s e i n n i t r o g e n r e t e n t i o n was accom-  d e c r e a s e i n u r i n a r y n i t r o g e n output.  I t i s clear  t h e r e f o r e t h a t i n c r e a s e d demand i s met by i n c r e a s e d e f f i c i e n c y i n u t i l i z i n g absorbed n i t r o g e n r a t h e r than by i n c r e a s e d a b s o r p t i o n .  They suggested  t h i s e f f i c i e n c y with, w h i c h t h e pregnant animal u t i l i z e s d i g e s t e d improves a s pregnancy advances.  that  nitrogen  The l e v e l s o f n i t r o g e n r e t a i n e d a t maximum  efficiency  ( e f f i c i e n c y o f u t i l i z a t i o n o f d i g e s t e d n i t r o g e n ) were 0.235 and 0 73  0.202 g./Kg.W  p e r day f o r t h e h i g h and low energy i n t a k e s r e s p e c t i v e l y .  Robinson and Forbes and  early lactation.  (1968) s t u d i e d ewe n u t r i t i o n d u r i n g l a t e pregnancy  D u r i n g pregnancy t h e h i g h and low l e v e l s o f energy 0 73  used were 150 and 125 K. c a l o r i e s m e t a b o l i z a b l e energy p e r Kg.W * p e r day where W=body weight i n Kg. and r e p r e s e n t e d 150.and 125% r e s p e c t i v e l y o f the maintenance requirement  o f non pregnant sheep.  These l e v e l s were e q u i -  v a l e n t t o d a i l y i n t a k e s o f 3270 and 2725 K. c a l o r i e s / 1 5 0 l b . ewe. The p r o t e i n l e v e l s used were 110, 82, 55, 27 g. o r (0.24, 0.18, 0.12, 0.05 l b . ) d i g e s t i b l e crude p r o t e i n d a i l y / 1 5 0 l b . ewe.  The two h i g h e r l e v e l s o f  p r o t e i n i n t a k e (0.24 and 0.18 l b . ) were used i n one experiment and two lower  levels  (0.12 and 0.05 l b . ) were used i n another  During  the f i r s t  d i e t intended day  experiment.  t h r e e weeks o f l a c t a t i o n ewes were g i v e n a h i g h energy 0 73  t o supply 250 K. c a l o r i e s o f m e t a b o l i z a b l e energy/Kg. W  (5450 K. c a l o r i e s / 1 5 0 l b . ewe) o r a low energy d i e t t o supply 175 K. f\  c a l o r i e s m e t a b o l i z a b l e energy/Kg.W  ~7 O  (3815 K. c a l o r i e s / 1 5 0 l b . ewe).  Both these d i e t s a l s o s u p p l i e d a s t a n d a r d d i g e s t i b l e crude p r o t e i n (D.C.P.) i n t a k e o f 8.8 g./Kg.W " ' o r 192 g. (0.42 l b . ) / 1 5 0 l b . ewe d a i l y . 0  73  D u r i n g g e s t a t i o n , r e s u l t s showed t h a t w i t h each energy l e v e l was a s m a l l decrease The  decrease  energy d i e t s .  there  i n dry matter i n t a k e with decreasing p r o t e i n i n t a k e .  i n m e t a b o l i z a b l e energy i n t a k e was pronounced on t h e lower I t was 2825 and 2237 K. c a l o r i e s f o r t h e h i g h and low  energy d i e t s , r e s p e c t i v e l y .  On each energy i n t a k e , crude p r o t e i n i n t a k e  was 156.5 and 64.5 g/150 l b . ewe p e r day on t h e h i g h e s t and lowest p r o t e i n diets,  respectively. The  d i f f e r e n c e between t h e r a t e s o f l i v e weight g a i n on t h e two energy  l e v e l s was about 0.06 Kg./day i n f a v o r o f t h e h i g h e r l e v e l .  The d i f f e r e n c e  13.  was  significant.  There was  a s i g n i f i c a n t i n t e r a c t i o n between p r o t e i n  and  energy i n d i c a t i n g a d i f f e r e n c e i n response t o p r o t e i n i n t a k e on each energy intake.  On the h i g h  energy i n t a k e  t h e r e was  between p r o t e i n l e v e l s (0.24 and 0.18 during  pregnancy but t h e r e was  levels  (0.12 and 0.5  a highly  no s i g n i f i c a n t d i f f e r e n c e  l b . D.C.P.) i n the f i r s t  experiment  a s i g n i f i c a n t d i f f e r e n c e between p r o t e i n  l b . D.C.P.) i n the second experiment.  There was  also  s i g n i f i c a n t d i f f e r e n c e between p r o t e i n l e v e l s between experiments.  There was  a highly  s i g n i f i c a n t c o r r e l a t i o n between the ewe weight l o s s  at p a r t u r i t i o n and the number o f lambs b o r n .  Ewes g i v i n g b i r t h  to twins  l o s t an average o f 3.2 Kg. more body weight at p a r t u r i t i o n than t h o s e g i v i n g b i r t h to s i n g l e s . during  A l t h o u g h the mean weight l o s s on the l o w e s t p r o t e i n  pregnancy was  0.5  Kg. g r e a t e r  than on the h i g h e s t  the d i f f e r e n c e due t o energy i n t a k e was significant. the  1 Kg.,  l o s s at p a r t u r i t i o n corrected  the l a s t  and  c a l c u l a t e d from  ten weeks o f pregnancy minus the weight  t o t w i n b i r t h s by c o v a r i a n c e .  body weight l o s s on a l l treatments except the two h i g h e s t w i t h t h e h i g h e r energy i n t a k e .  protein intake,  t h e s e d i f f e r e n c e s were n o t  The n e t body weight change o f the ewes was  g a i n i n body weight d u r i n g  intake  There was  i n net body weight l o s s between the h i g h  There was  protein  a net  intakes  a highly significant difference and low energy i n t a k e s .  There  was  no s i g n i f i c a n t p r o t e i n x energy i n t e r a c t i o n s i n the mean b i r t h weights and no s i g n i f i c a n t d i f f e r e n c e due t o energy i n t a k e .  A l t h o u g h t h e r e were no  s i g n i f i c a n t d i f f e r e n c e s i n lamb b i r t h weights between p r o t e i n i n t a k e s  within  experiments, the b i r t h weight o f lambs b o r n from ewes on the lower p r o t e i n i n t a k e s were g e n e r a l l y and 3.51  v s . 4.61  lower than those from h i g h e r p r o t e i n i n t a k e s  and 4.59  Kg./lamb).  As a r e s u l t the combined  o f p r o t e i n l e v e l s between experiments was s i g n i f i c a n t .  (3.98  comparison  14.  There was the f i r s t  a s i g n i f i c a n t c o r r e l a t i o n between the ewe weight change d u r i n g  t h r e e weeks o f l a c t a t i o n and the number of lambs s u c k l e d .  s u c k l i n g twins l o s t an average 0 . 1 1 suckling singles.  There was  Ewes  Kg. more body weight per day than t h o s e  a l a r g e v a r i a t i o n between ewes w i t h i n t r e a t m e n t s .  There were no s i g n i f i c a n t i n t e r a c t i o n s between p r o t e i n and energy  intakes  d u r i n g pregnancy o r between treatments d u r i n g pregnancy and treatments d u r i n g lactation.  There was  no s i g n i f i c a n t d i f f e r e n c e i n weight l o s s between the  two energy i n t a k e s imposed d u r i n g pregnancy. 0.16  The mean l o s s e s were 0 . 1 5  Kg./day on h i g h and low l e v e l s , r e s p e c t i v e l y .  The d i f f e r e n c e i n l o s s  of body weight between h i g h and low energy treatments d u r i n g l a c t a t i o n not s i g n i f i c a n t .  and  Ewes on the lower l e v e l s o f p r o t e i n i n t a k e d u r i n g  was  pregnancy  i n each experiment tended t o l o s e l e s s weight d u r i n g l a c t a t i o n than those on the h i g h e r l e v e l s but the d i f f e r e n c e s were not s i g n i f i c a n t . between combined  p r o t e i n l e v e l s between experiments was  The  difference  significant.  Lambs b o r n from ewes on lower p r o t e i n i n t a k e s d u r i n g pregnancy had on average a slower growth r a t e  (0.26  and 0 . 2 3  versus 0 . 3 1  r a t e f o r lower and h i g h e r p r o t e i n l e v e l s , r e s p e c t i v e l y ) .  and 0 . 3 0  Kg./day  growth  The d i f f e r e n c e i n  growth r a t e between p r o t e i n i n t a k e s between the two experiments was  signi-  ficant. A summary o f the r e s u l t s i n d i c a t e s t h a t ewe l i v e weight l o s s  during  e a r l y l a c t a t i o n , lamb growth r a t e s from b i r t h to t h r e e weeks and ewe m i l k y i e l d a t 3 weeks tended to d e c r e a s e w i t h d r e c r e a s i n g p r o t e i n i n t a k e  (156,  119,  ms.:  90 and 65 g. D . C . P . / 1 5 0 l b . ewe  d a i l y ) d u r i n g pregnancy.  There  no s i g n i f i c a n t d i f f e r e n c e i n weight l o s s o f ewes between the two intakes, imposed  d u r i n g pregnancy.  amount o f m i l k ( 0 . 6 0  energy  Ewes s u c k l i n g twins produced a g r e a t e r  Kg./day more) than t h o s e s u c k l i n g s i n g l e s .  There were  15.  no s i g n i f i c a n t i n t e r a c t i o n s  between p r o t e i n  and energy i n t a k e s  during  pregnancy o r between pregnancy x l a c t a t i o n . F u r t h e r work c a r r i e d early  out on ewe n u t r i t i o n d u r i n g l a t e pregnancy and  l a c t a t i o n has i n d i c a t e d  t h a t l e a n ewes have a h i g h e r e f f i c i e n c y o f  food c o n v e r s i o n t o m i l k . Peart  (1968) s t u d i e d t h e e f f e c t s  o f B l a c k f a c e ewes. of d r i e d  o f l i v e weight on the m i l k p r o d u c t i o n  Ewes were i n d i v i d u a l l y  fed a pelleted  feed  consisting  grass meal 66%, maize meal 18%, soybean meal 10%, and molasses 5%,  w i t h v i t a m i n and m i n e r a l a d d i t i o n s .  The feed c o n t a i n e d 66 g. d i g e s t i b l e  o r g a n i c matter (D.O.M.) p e r 100 g. as determined i n v i v o and i n v i t r o . s i x weeks ,x pre-partum the f i r s t D.O.M./Kg. l i v e w e i g h t .  At  and second group o f ewes were g i v e n 14 g.  The t h i r d group r e c e i v e d 9.2 g. D.O.M./Kg.  During  the  l a s t 6 weeks o f pregnancy t h e mean t o t a l d a i l y f o o d i n t a k e o f ewes i n  the  first  and second group i n c r e a s e d from 912 t o 1182 g. D.O.M. and t h a t  o f t h i r d group i n c r e a s e d from 736 t o 980 g. D.O.M. and throughout l a c t a t i o n  Immediately  after  parturition  f e e d was r a t i o n e d t o t h e ewes a c c o r d i n g t o t h e i r i n d i -  v i d u a l _p^st^p^r_tum l i v e w e i g h t s .  D u r i n g l a c t a t i o n t h e ewes were f e d 9.2 g.  D.O.M./Kg. based on t h e i r immediate post-partum l i v e w e i g h t s , p l u s an a l l o w ance f o r a p r e d i c t e d l e v e l o f m i l k p r o d u c t i o n .  A l l groups o f ewes make s i m i l a r  l i v e weight g a i n s i n l a t e pregnancy and mean b i r t h weights o f t h e lambs were also  similar.  Ewes i n t h e f i r s t  and second group were f e d 0.5 and ewes i n  the  t h i r d group 0.25 g. D.O.M./g. o f p r e d i c t e d m i l k p r o d u c t i o n .  was  increased after  first  and second weeks o f l a c t a t i o n ,  The r a t i o n  then m a i n t a i n e d a t  a c o n s t a n t l e v e l f o r t h e remainder o f l a c t a t i o n .  The mean d a i l y m i l k produc-  tion- o f ewes i n f i r s t  and t h e y i e l d o f each o f  and t h i r d group was s i m i l a r  these groups was s i g n i f i c a n t l y g r e a t e r than t h a t o f ewes i n t h e second The mean t o t a l m i l k p r o d u c t i o n o f ewes, d u r i n g 10 weeks o f l a c t a t i o n ,  group. suckling  16.  twin lambs was 127, 108, and 142 Kg. f o r the f i r s t , group, r e s p e c t i v e l y . and  second  and t h i r d  The mean l i v e weight changes o f ewes i n t h e f i r s t  t h i r d group were s i m i l a r d u r i n g l a c t a t i o n .  g a i n o f twin lambs i n the f i r s t ,  second  The mean d a i l y  l i v e weight  and t h i r d group was 279, 275 and  284 g, and o f s i n g l e s , 318, 300 and 319 g., r e s p e c t i v e l y .  The evidence  i n d i c a t e d t h a t ewes i n l e a n body c o n d i t i o n have a h i g h e r e f f i c i e n c y o f food c o n v e r s i o n t o m i l k . There a r e breed d i f f e r e n c e s i r i m i l k p r o d u c t i o n .  S l e n , C l a r k and  Hironaka'(1963) made a comparison o f m i l k p r o d u c t i o n and i t s r e l a t i o n t o lamb growth i n f i v e breeds  o f sheep namely S u f f o l k , Hampshire, R a m b o u i l l e t , .  Canadian C o r r i e d a l e and Romnelet ewes.  T h e i r r e s u l t s i n d i c a t e d t h a t ewes  n u r s i n g twins y i e l d e d s i g n i f i c a n t l y more m i l k than those n u r s i n g s i n g l e s and S u f f o l k s y i e l d e d s i g n i f i c a n t l y more than o t h e r breeds. twins S u f f o l k s and C o r r i e d a l e s y i e l d e d most.  Of ewes n u r s i n g  S i n g l e lambs gained more  l i v e weight than twins and those g a i n s were h i g h l y c o r r e l a t e d w i t h m i l k consumption.  P r o t e i n and f a t c o n t e n t d i d n o t d i f f e r between b r e e d s .  III.  EARLY WEANING AND FEEDING OF LAMBS  C l a r k (1954) s t a t e d t h a t e a r l y weaning c o n f e r s great  f l e x i b i l i t y in  s t o c k management, e s p e c i a l l y i n r e s p e c t t o s h e a r i n g , p a s t u r e  u t i l i z a t i o n and  weed c o n t r o l . Wardrop  (1960) has shown t h a t , at about 8 weeks o f age, g r a z i n g  can d i g e s t forage w i t h  the e f f i c i e n c y of an a d u l t .  This  lambs  i n d i c a t e d the minimum  age at which lambs can be weaned on t o p a s t u r e . B a i r d , McCampbell, N e v i l l e , C o i r d i a , B i z z e l l a n d S e l l most o f the m i l k p r o d u c t i o n  (1960) found that  o f ewes had ceased by 15 weeks a f t e r  lambing and  C l a r k (1961) s t a t e d t h a t f o r ewes n u r s i n g twins the m i l k p r o d u c t i o n f i r s t week of l a c t a t i o n was approximately  double the p r o d u c t i o n  of the  of the e i g h t h  week. Dickson  (1959) suggested t h a t a f t e r two months of age, grass becomes the  dominant f a c t o r i n the lamb's f e e d .  T h i s a l s o i n d i c a t e s t h a t lambs can be  weaned e a s i l y at 8 weeks o f age but some workers have shown t h a t e a r l y weaned lambs do not g a i n as much, when weaned on t o p a s t u r e ,  as unweaned lambs.  D i f f e r e n t responses t o e a r l y weaning have been r e p o r t e d .  Stage o f m a t u r i t y  of the p a s t u r e  Many workers have  pointed  i s an important  f a c t o r f o r e a r l y weaning.  out t h a t lambs weaned at 8 t o 10 weeks o f age should have at l e a s t  12 t o 14% crude p r o t e i n i n t h e i r feed d u r i n g f i r s t 3-4 weeks a f t e r weaning. B a i r d e_t al_ (1960) weaned lambs at an average age o f 76 days and an average weight of 45 l b . , on t o w i n t e r grass.  temporary pastures  E a r l y weaning d i d not s t i m u l a t e forage  d a i l y g a i n f o r unweaned and weaned lambs was So e a r l y weaned lambs made slower gains experiment.  of wheat and rye  consumption of lambs.  0.57  and 0.51  Average  lb., respectively.  than the unweaned c o n t r o l s i n t h i s  They a l s o s t a t e d t h a t e a r l y weaned lambs had 46% l e s s worms  18. at s l a u g h t e r than the lambs weaned l a t e r  (764 v s . 1407).  B r o t h e r s and Whiteman (1961) s t u d i e d the i n f l u e n c e o f e a r l y weaning on c r e e p - f e d m i l k lambs when weaned on weight or age b a s i s .  A l l lambs and  t h e i r dams;: were on wheat p a s t u r e and the lambs were c r e e p - f e d . first  In the  year the average weight of lambs at weaning was 54 l b s . and average  weaning age was 76 days.  The weaned lambs made an average d a i l y g a i n from  weaning t o market weight  (90 l b . ) o f 0.52  0.54 l b . / d a y .  l b . and lambs not weaned gained  T h i s d i f f e r e n c e was not s i g n i f i c a n t .  In another experiment  d u r i n g the f o l l o w i n g year the average weight o f lambs at weaning was 46 l b . and average weaning age was the lambs not weaned, 0.52 showed  62 days. lb./day.  t h a t e a r l y weaned lambs  The weaned lambs gained 0.47 T h i s d i f f e r e n c e was  l b . and  significant.  This  (about 9 weeks o l d ) made slower gains than  l a t e weaned (about 11 weeks o l d ) lambs. lambs weaned at e i g h t weeks o f age may  Cannon  (1960) s t a t e d t h a t f a t  average a minimum of 2.5  l b . less  i n c a r c a s s weight than s u c k l i n g lambs when both types have been under extremely good n u t r i t i o n a l not a f f e c t e d by weaning.  conditions. Wardrop  Under such c o n d i t i o n s g r a d i n g was  (1960) r e p o r t e d t h a t lambs weaned at 7,  10, 13 or 18 weeks o f age and g r a z i n g h i g h p r o t e i n p a s t u r e s grew w e l l and t h e r e were no s i g n i f i c a n t d i f f e r e n c e s between t h e i r grades and d r e s s i n g p e r c e n t a g e s .  equally  carcass w e i g h t s ,  However, when g r a z i n g p a s t u r e s i n the pre-'  f l o w e r i n g and f l o w e r i n g stages of growth, lambs weaned at 8 weeks o f age d i d not grow as w e l l as unweaned c o n t r o l s . and i t was protein.  T h e i r c a r c a s s weights were a l s o lower  suggested t h a t the d i f f e r e n c e s were p r i m a r i l y due t o an inadequate They s t a t e d  that stage o f m a t u r i t y of the p a s t u r e i s v e r y  f a c t o r f o r e a r l y weaning.  important  They p o i n t e d out t h a t the m i l k i n t a k e of the 10-  week o l d g r a z i n g lamb i s about 1.6 lb./day which i s e q u i v a l e n t t o 2.3 l b . of S.E. ( s t a r c h e q u i v a l e n t ) and 0.6 l b . of d i g e s t i b l e  crude p r o t e i n  (D.C.P.)  19.  per week.  T h e r e f o r e i f a lamb i s weaned a t 10 weeks of age and i s to g a i n  as f a s t as unweaned lambs i t must o b t a i n these a d d i t i o n a l amounts o f S.E.' and D.C.P. from the p a s t u r e .  Only about 22 lb./week o f f r e s h young g r a s s  are r e q u i r e d but a t l e a s t twice as much w i l l be needed when the herbage i s i n the f l o w e r i n g s t a g e .  T h i s l a r g e i n c r e a s e i n the a d d i t i o n a l herbage r e q u i r e -  ment i s o c c a s i o n e d by the r a p i d d e c l i n e i n p a s t u r e p r o t e i n c o n t e n t .  As the  p a s t u r e i n t a k e of the lamb i s l i m i t e d , so when the lamb i s g r a z i n g a mature p a s t u r e i t i s i m p o s s i b l e f o r the lamb t o i n g e s t enough herbage to meet i t s p r o t e i n requirements  and adequate energy  Cameron and Hamilton  (1961) found  a lower d r e s s i n g percentage  to s u s t a i n s a t i s f a c t o r y growth.  t h a t lambs weaned a t 10 weeks of age had  than those weaned a t 15 or 20 weeks of age.  ever, age a t weaning had no s i g n i f i c a n t e f f e c t on c a r c a s s s c o r e s . found  the s i n g l e lambs h e a v i e r a t market and h a v i n g lower d r e s s i n g  than twins.  The lower d r e s s i n g percentage  w i t h a younger average  i s t i c s than those f o r twin lambs.  developed  percentage  carcass  scores f o r a l l other carcass characterThey p o i n t e d out t h a t lambs weaned a t 10  weeks o f age made more r a p i d average than d u r i n g the remainder  They a l s o  f o r s i n g l e lambs was a s s o c i a t e d  age a t s l a u g h t e r and s i g n i f i c a n t l y lower  s c o r e f o r f i n i s h , and lower average  How-  g a i n s i i i the f i r s t  two weeks f o l l o w i n g  o f t h e study, i n d i c a t i n g t h a t rumen f u n c t i o n was  s u f f i c i e n t l y f o r the d i g e s t i o n o f immature f o r a g e .  s t a t e d t h a t age a t weaning had no e f f e c t on d e a t h l o s s e s .  1  They f u r t h e r  S i n g l e lambs  made f a s t e r g a i n s than twins and wethers made more r a p i d g a i n s than ewes. Franklin  Q.965) weaned merino lambs a t d i f f e r e n t ages on to a m i x t u r e of  roughage and g r a i n . of age was and  R e s u l t s showed  t h a t l o s s o f lambs weaned a t f o u r weeks  s i g n i f i c a n t l y g r e a t e r than i n those weaned a t 6, 8, or 12 weeks  lambs w h i c h s u r v i v e d were s i g n i f i c a n t l y h e a v i e r a t b i r t h and a t weaning.  L i v e weight a t 22 weeks o f age was n o t s i g n i f i c a n t l y a f f e c t e d by age a t weaning.  F i e l d observations, showed  t h a t lambs between 8 and 16 weeks- of age c o u l d  20.  be weaned successfully under drought conditions on the roughage and concentrate provided they were closely confined until accustomed to their rations. Garrigus (1951) concluded that relatively simple creep rations were as effective i n promoting rapid gains i n early weaned lambs as more complicated grain mixes. Perry, Beeson, and Harper (1957) studied the value of f o r t i f i e d creep rations for single and twin suckling lambs.  The creep ration containing  crude protein was available from the third day of lamb's l i f e .  17$  Single lambs  receiving creep pellets containing corn, soybean meal, salt, bone meal and vitamin 1,D"and"E grew as rapidly as lambs fed similar pellets but fortified with 10% sugar, B vitamins, ascorbic acid and trace minerals (super pellets). Twins which had access to "super pellets" grew as rapidly as single lambs not on "super pellets". Growth of twins was not as rapid as that of single lambs when both received "super pellets." Hinds, Mansfield and Lewis (1963) indicated' that the most rapid gains were obtained with lambs weaned at 10 weeks of age and receiving 12 percent protein. Ranhotra and Jordan (1966) conducted experiments to determine the optimum level of protein for lambs weaned at 6 to 8 weeks of age and to determine the energy requirements of such lambs as measured by digestion t r i a l s and growth studies.  Their results revealed that apparent digesti-  b i l i t y of both protein and energy were increased significantly due to increased protein and energy content of the ration. Protein content of the ration was without significant effect upon rate of gain or efficiency of feed conversion, when measured on the basis of either 8 or 9-week feeding periods.  However, rations containing between 12 and 1L% protein resulted i n  21.  more r a p i d g a i n s d u r i n g the f i r s t w i t h lower p r o t e i n l e v e l s .  28 days f o l l o w i n g weaning than  Rations c o n t a i n i n g 16.5  not s u p p o r t more r a p i d o r more e f f i c i e n t  to 16.7%  rations  protein did  gains than r a t i o n s c o n t a i n i n g  to  14% p r o t e i n .  They f u r t h e r i n d i c a t e d t h a t r a t i o n s based  to  roughage r a t i o supported s i g n i f i c a n t l y g r e a t e r and more e f f i c i e n t  of  lambs weaned a t 7 weeks o f age d u r i n g the f i r s t  based on a 55:45 c o n c e n t r a t e to roughage r a t i o .  on 75:25 c o n c e n t r a t e  Light  gains  4 weeks than d i d r a t i o n s  Over the 8 week p e r i o d gains  were g r e a t e r w i t h the h i g h e r c o n c e n t r a t e r a t i o n than w i t h the lower trate ration.  13.5  However, these d i f f e r e n c e s were not  concen-  significant.  (1966) i n d i c a t e d i n a f r e e c h o i c e o f d i f f e r e n t  feeding stuffs  t h a t r o l l e d b a r l e y and oats were more r e a d i l y accepted than cracked maize by the lambs weaned a t 5 weeks of age. r a t i o n w i t h 21% Coetzee  He  a l s o s t a t e d t h a t lambs s e l e c t e d a  protein.  and Vermeulen (1966) f e d merino lambs, 10 weeks b e f o r e and 6  weeks a f t e r weaning, creep feeds w i t h 9, 15 o r 20%  crude p r o t e i n .  p o i n t e d out t h a t weight g a i n of c r e e p - f e d lambs was  significantly  than f o r the c o n t r o l group. p r o t e i n was suggested  significantly  Results greater  A f t e r weaning g a i n o f groups g i v e n 15 o r  g r e a t e r than those g i v e n 9% p r o t e i n b u t  20%  results  t h a t 9% p r o t e i n b e f o r e weaning and 15% p r o t e i n a f t e r w a r d s would  g i v e b e s t performance. Heated soybean meal has been used t o cause g r e a t e r n i t r o g e n r e t e n t i o n by many workers.  Glimp, K a r r , L i t t l e , W o o l f o l k , M i t c h e l l , J r . and Hudson  (1967) r e p o r t e d t h a t reduced p r o t e i n s o l u b i l i t y r e t e n t i o n and decreased (1969) a l s o experimented bility  resulted i n increased nitrogen  r u m i n a l d e g r a d a t i o n o f f e e d p r o t e i n i n lambs. t o determine  the e f f e c t s of r e d u c i n g p r o t e i n  Hudson e t a l . solu-  from 72 t o 35% by dry h e a t and the e f f e c t of f e e d i n g t h r e e l e v e l s  of  10,  12  and  14%,  crude p r o t e i n on r a t e and  u t i l i z a t i o n o f e a r l y weaned lambs. highest  a t the 14%  consistent  protein level.  e f f e c t and  e f f i c i e n c y of g a i n and  Results  showed t h a t growth r a t e  H e a t i n g the soybean meal had  f e e d e f f i c i e n c y was  improved s i g n i f i c a n t l y . increased  and  the soybean meal.  ficial  due  to h e a t i n g  growth i m p a i r i n g  Results  with protein  e f f e c t of p r o p e r treatment i s the r e s u l t of g r e a t e r  several thermo-labile  bene-  destruction  f a c t o r s than of soya p r o t e i n  Johnson (1958) a t t r i b u t e d the poor growth of animals on  containing  raw  of  itself. diets  soybean meal to an i n h i b i t i o n of i n t e s t i n a l p r o t e o l y s i s ,  h a e m a g g l u t i n i n a c t i v i t y of some component of the beans and of d i e t a r y amino a c i d s .  From the r e f e r e n c e s  lambs s h o u l d have a t l e a s t 12  feeding  level  The  F i s h e r and  the f i r s t  was  an i n -  a l s o showed t h a t rumen ammonia c o n c e n t r a t i o n s showed a s l i g h t d e p r e s s i o n  nutrient  to 14%  r e s u l t s i n greater  nitrogen  inbalance  g i v e n above i t i s c l e a r t h a t  crude p r o t e i n i n t h e i r r a t i o n  few weeks, when weaned a t 8 to 10 weeks of age  the heated soybean meal by  an  reducing  retention.  and  its solubility  during  further  from 72 to  that 35%  23. IV.  The  UREA-NUTRITIONAL IMPORTANCE AS A NON-PROTEIN NITROGEN SOURCE  first  purpose o f adding n o n - p r o t e i n n i t r o g e n  compounds to  r a t i o n o f ruminants i s to s u p p l y n i t r o g e n which can be p r o t e i n by nitrogen The  the m i c r o b i a l p o p u l a t i o n  used by  (1940) was  nitrogen  one  c o u l d be  o f the  used by  first  He  on a l o w - p r o t e i n ,  semipurified  among the  first  the c o n v e r s i o n  reported  urea.  t o p i c and it  nitrogen  to t e s t the  theory t h a t n o n - p r o t e i n  d i e t made up o f s t a r c h , a l k a l i washed straw,  Wegner, Booth, Bohstedt and  Hart  to f i n d t h a t the l e v e l of p r o t e i n i n the of non-protein n i t r o g e n  to p r o t e i n and  increased,  o f u r e a to p r o t e i n decreased. the u s e f u l n e s s  To  o f u r e a as a NPN  i s n e c e s s a r y to d i s c u s s b r i e f l y  the  (1940) were  ration influenced  to f i n d t h a t as  the amount and discuss  the  (non-protein  r a t e of deamination i s o n l y s l i g h t l y t h a t the l e v e l of f r e e amino a c i d s ml  r a t i o n , when i t may  urea. hydrolysis The  l e s s than t h a t of t h e i r p r o d u c t i o n ,  i n rumen i s low  (of the o r d e r of 1  so  mg.  a protein-rich  f i v e f o l d Co t e n f o l d f o r a s h o r t  B l a c k b u r n (1965) i n d i c a t e d t h a t the end  period.  p r o d u c t s of i n d i v i d u a l amino  a c i d s i n most cases are ammonia, carbon d i o x i d e Abou Akkada and  the  the r u m i n a l b a c t e r i a .  r u m i n a l f l u i d ) , except a f t e r f e e d i n g increase  of  n i t r o g e n ) source  f a t e of p r o t e i n and  o f d i e t a r y p r o t e i n are r a p i d l y deaminated by  rate  the  above mentioned  Annison (1956) s t a t e d t h a t the amino a c i d s produced by  amino N per 100  to  t h a t lambs gained weight when they were kept  l e v e l of p r o t e i n i n the r a t i o n was conversion  the rumen m i c r o f l o r a .  rumen microorganisms to form p r o t e i n u s e f u l  the h o s t animal.  i n o r g a n i c s a l t s and  into  reaction:-  N o n - p r o t e i n nitrogen-»microbial p r o t e i n Harris  incorporated  of the rumen or to p r o v i d e o t h e r  c o n t a i n i n g molecules which can be  b a s i s o f t h i s mechanism i s the  the  and  volatile  fatty acids.  B l a c k b u r n (1963) have shown t h a t l e s s e r amounts o f ammonia  24. are a l s o produced  i n the rumen by the a c t i o n o f ami dases on glutamine  asparagine and the ami de groups o f p r o t e i n s .  and  The p r o d u c t i o n o f ammonia  from the above sources can r e s u l t i n v e r y h i g h l e v e l s i n the rumen, f o r example, Johns (1955) has r e p o r t e d upto 130 mg.  ammonia n i t r o g e n per 100  ml.  o f r u m i n a l f l u i d i n sheep on h i g h p r o t e i n p a s t u r e s but t h i s i s much h i g h e r than the ammonia l e v e l normally found i n the rumen when u r e a o r o t h e r forms of supplementary  N.P.N, are f e d under p r a c t i c a l  conditions.  Endogenous urea e n t e r s the rumen w i t h the s a l i v a and through ruminal w a l l .  In sheep, McDonald (1948) e s t i m a t e d t h a t 0.5  day i s i n t r o d u c e d i n t o the rumen w i t h the s a l i v a .  the  g. u r e a N per  Houpt (1959) r e p o r t e d  t h a t 16 times as much u r e a passed d i r e c t l y from b l o o d to rumen as moved w i t h the s a l i v a but i n t h i s case the animal was c o n c e n t r a t i o n of urea was  the  g r e a t e r i n the b l o o d than i n the rumen so more  u r e a passed from the b l o o d to the rumen then was Urea i s broken  n o t f e d u r e a and  r e c y c l e d w i t h the §aliva  down v e r y r a p i d l y t o ammonia and carbon d i o x i d e by the ureases  o f ruminal b a c t e r i a so t h a t the u r e a l e v e l i n the rumen i s n e g l i g i b l e . r e s u l t o f the s e c r e t i o n and h y d r o l y s i s o f endogenous u r e a i s t h a t the i s a b l e to m a i n t a i n a low but s i g n i f i c a n t rumen, even when i t i s s t a r v e d .  The animal  c o n c e n t r a t i o n o f ammonia i n the  When u r e a i s g i v e n as a  supplementary  source o f n i t r o g e n , i t shares the f a t e of endogenous u r e a i n the rumen. The urease a c t i v i t y o f the r u m i n a l b a c t e r i a o f animals on unsupplemented r a t i o n s i s s u f f i c i e n t l y h i g h to b r i n g about  the breakdown o f l a r g e amounts  o f added u r e a w i t h i n a s h o r t time, and l i t t l e  o r no i n c r e a s e i n a c t i v i t y  occurs when the animals are c o n d i t i o n e d to b e i n g f e d u r e a f o r l o n g p e r i o d s . Repp, H a l e , Cheng and Burroughs (1955) s t a t e d t h a t the e n t r a n c e o f l a r g e q u a n t i t i e s o f u r e a i n t o the rumen i n s t a r v e d o r f a s t e d animals  or  by r a p i d consumption o f feeds c o n t a i n i n g u r e a by animals not p r e v i o u s l y f e d such r a t i o n s , r e s u l t s i n the r e l e a s e o f ammonia a t a r a t e which does not  25.  permit e f f i c i e n t u t i l i z a t i o n of nitrogen by the rumen micro-organisms f o r the synthesis of c e l l u l a r protein.  The hydrolysis of urea i n the rumen i s unrelated  to the a b i l i t y of micro-organisms to u t i l i z e ammonia produced.  Ammonia not  u t i l i z e d by the rumen microflora i s rapidly absorbed into the bloodstream where i t may  reach toxic l e v e l s . These workers f u r t h e r indicated that toxic symptoms  appear i n sheep when bloodaamonia nitrogen l e v e l r i s e s above 1 mg.  %,  Warren (1962) pointed out that the rate of ammonia transfer across  the  rumen wall not only depends on the concentration gradient but also on pH of the rumen l i q u o r .  He stated that ammonia i s most toxic i n conditions where the  pH of the rumen l i q u o r i s higher than 7.5,  when unionized NH^  i s formed and  most membranes are more permeable to the NH^ moiety than the ammonium i o n (NH^  +  Kammlade, M i t c h e l l and Sleeter (1940) as c i t e d by Briggs  ).  (1967) stated  that up to one-third of the nitrogen i n a sheep r a t i o n could be s a f e l y replaced by urea.  They also stated that the rate of conversion of urea into b a c t e r i a l  p r o t e i n decreased as the t o t a l protein, excluding non-protein nitrogen, of the r a t i o n increased above 12% of dry matter.  .They also showed that the urea above 12% p r o t e i n l e v e l was  not retained as  e f f i c i e n t l y as casein and other p r o t e i n sources, and that urea i n the ruminant r a t i o n exerted no adverse e f f e c t on f l a v o r and non-protein nitrogen content of meat and milk.  Although the use of urea as a p r o t e i n substitute i n ruminant  n u t r i t i o n has become f a i r l y common i n North America, i t s use as the major or sole source of nitrogen i s l i m i t e d due to danger of ammonia t o x i c i t y .  26. The adverse effects of urea may be eliminated partially through the use of more slowly hydrolyzed, less toxic non-protein nitrogen compounds. Biuret i s a compound of interest. less toxic than urea.  It was shown by Repp e_t a l (1955) to be  However Anderson, McLaren, Welch, Campbell and Smith  (1959) stated that when pure biuret supplied 100% of the supplemental nitrogen instead of urea, nitrogen utilization was significantly  depressed.  They also stated that nitrogen digestibility was greater when purified soybean protein or a nitrogen equivalent mixture of urea and creatine replaced urea as the source of supplemental nitrogen. - In order to compare urea with other non-protein nitrogen sources Schaadt, Johnson and McClure (1966) investigated adaptation to urea, biuret and diammonium phosphate as non-protein nitrogen sources for sheep.  The crude  protein content of control and supplemented rations was 6.5 and 10.2% respectively on a dry matter basis.  The results showed that percent diges-  t i b i l i t y of nitrogen i n the control animals, fed on chopped wheat straw, chopped timothy hay, ground shelled corn and corn starch, and given no supplementary non-protein nitrogen, was significantly lower than in any other group and in the group given urea i t was significantly higher than i n a l l groups except that given urea with diammonium phosphate.  Nitrogen  balance was greatest with no supplement or with urea and diammonium phosphate. They also reported that as the t r i a l progressed there was an increase i n nitrogen balance i n the group given urea but not i n other groups. It showed that rumen microorganisms became better adapted to feeding of urea for the synthesis of microbial protein as the t r i a l progressed but the biuret supplemented lambs failed to show the evidence of adaptation i n nitrogen balance but they did show adaptation in the urinary biuret excreted because biuret excreted by the group given i t decreased during  27.  the  trial. Schaadt  e_t a l (1966) a l s o s t u d i e d the p a l a t a b i l i t y o f f o u r r a t i o n s  supplemented  e q u a l l y on a n i t r o g e n b a s i s w i t h soybean meal (SBM), u r e a ,  diammonian phosphate  (DAP)  and diammonium phosphate  were p r e v i o u s l y adapted  to the b a s a l , u r e a o r ADP  d e s i g n o f the t r i a l was  such t h a t each lamb was  + urea.  Lambs used  + urea r a t i o n s .  exposed  The  f o r a one week  p e r i o d to each p o s s i b l e combination o f two supplemental feeds but to o n l y two  i n any one p e r i o d .  r a t i o n was period.  Animals  a t e a d - l i b i t u m and p a l a t a b i l i t y o f the  c a l c u l a t e d by the amount o f each r a t i o n eaten over a s i x week  R e s u l t s showed t h a t the d a i l y i n t a k e f o r SBET o r u r e a was  2.77  kg; f o r SBM  o r DAP,  0.52  k g ; f o r u r e a o r DAP,  0.35  kg and f o r DAP  1.14  and 0.40  1.19  and 0.26  + u r e a o r DAP,  1.18  kg; f o r SBM  o r DAP  and 0.21  (DAP)  o r DAP  phosphate  very unpalatable.  Some workers have compared u r e a w i t h melamine.  + u r e a , 1.16  and  Results  Diammonium  phosphate  In a l l p e r i o d s , diammonium  C r o n j e and Coetzee  (1966)  the r e t e n t i o n o f n i t r o g e n i n sheep g i v e n a c o n t r o l f e e d based  p e l l e t e d d r i e d T. t r i a n d r a g r a s s . when r e c e i v i n g t h i s g r a s s . tube.  and  r a t i o n s were e q u a l l y  + Urea.  p r e f e r r e d over diammonium phosphate.  determined  + u r e a , 1.06  kg r e s p e c t i v e l y .  p l u s u r e a was was  and  kg, f o r u r e a o r DAP  r e v e a l e d t h a t both u r e a and soybean meal supplemented p r e f e r r e d over diammonium phosphate  0.75  T h i s n i t r o g e n was  on  The sheep were i n n e g a t i v e n i t r o g e n b a l a n c e  They were g i v e n 4.7  g. n i t r o g e n d a i l y by stomach  p r o v i d e d by 10 gi . u r e a o r 7 gii.  melamine d a i l y .  The  animals r e v e r t e d to a p o s i t i v e b a l a n c e when dosed w i t h n o n - p r o t e i n n i t r o g e n . A s i g n i f i c a n t l y l a r g e r amount o f n i t r o g e n was and u r e a than i n the c o n t r o l a n i m a l s .  e x c r e t e d : i n the case o f melamine  This i n d i c a t e d that a considerable  amount o f n i t r o g e n from these substances wasnot p r o p e r l y u t i l i z e d by sheep e x c r e t e d through the u r i n e .  and  The s i g n i f i c a n t l y h i g h e r n i t r o g e n content of the  28.  faeces o f sheep r e c e i v i n g melamine i n d i c a t e d t h a t p a r t o f melamine n i t r o g e n was  excreted  excreted  through the f a e c e s .  i n the f a e c e s .  urea group c o n t a i n e d  Urea n i t r o g e n , on  T h i s i s i l l u s t r a t e d by  no more n i t r o g e n  gen  not  statistically  f o r urea, melamine and  higher  significant.  c o n t r o l s was  increased  significantly  Adaptation toxicity^;, e f f e c t on  i n the  D a i l y r e t e n t i o n of  f o r e i g h t hours a f t e r u r e a had  -0.87g.  nitroNon  been g i v e n .  f e e d i n g urea to a v o i d  l e v e l of r e a d i l y fermentable c a r b o h y d r a t e a l s o has  the l e v e l of absorbed  Al-  not a f f e c t e d by melamine but  o f the animal i s important w h i l e  The  an  nitrogen.  Szabo (1965) s t a t e d t h a t f o r wethers the amount o f urea per head day  c o u l d be g r a d u a l l y i n c r e a s e d  poisoning  but  not  than f o r melamine,  +.50g., +0.94g. and  p r o t e i n n i t r o g e n i n b l o o d as urea n i t r o g e n was it  the f a c t t h a t faeces  than t h a t of the c o n t r o l group.  though average n i t r o g e n r e t e n t i o n f o r urea was the d i f f e r e n c e was  the other hand, was  from 15  to 40g.  the i n c r e a s e must be g r a d u a l  per  w i t h o u t the r i s k of  t a k i n g a t l e a s t 30 days to  reach  the maximum. McLaren, Anderson, T s a i and  Barth  l e n g t h o f time of urea f e e d i n g and d r a t e s on  significantly  of urea f e e d i n g up constant.  l e v e l of r e a d i l y fermentable carbohy-  the r e t e n t i o n of absorbed n i t r o g e n .  r e t e n t i o n o f absorbed n i t r o g e n by was  (1965) examined the i n f l u e n c e of  The  lambs, w i t h  Results initial  improved by 3 percentage u n i t s w i t h to 45 days.  During  the  last  fermentable c a r b o h y d r a t e s ranged from 564 725g.  r e t e n t i o n o f 367„, each 10 day  period  significantly  was  improved  c a l o r i e s i n c r e a s e of r e a d i l y ferment-  a b l e c a r b o h y d r a t e s i n the r a t i o n of the lambs.  d a i l y dry matter i n t a k e was  the  10 days the r e t e n t i o n  r e t e n t i o n of absorbed n i t r o g e n was  by 2 percentage u n i t s f o r each 100 K.  showed that  The  to 1178  K.  i n t a k e of r e a d i l y calories/day.  Average  Improvement i n the r e t e n t i o n of absorbed  n i t r o g e n due to the l e v e l o f r e a d i l y observed  fermentable c a r b o h y d r a t e s was  i n lambs r e g a r d l e s s o f the degree  o f t h e i r adaptation to urea  feeding. Addition of r e a d i l y fiber d i g e s t i b i l i t y .  fermentable c a r b o h y d r a t e decreased  When 5 6 4  K . c a l o r i e s / d a y of r e a d i l y  c a r b o h y d r a t e s were f e d to 5 lambs the average was  4 5 . 6 7 o .  When the l e v e l o f r e a d i l y  i n c r e a s e d to 1 1 7 3 crude f i b e r was  crude f i b e r  the crude  fermentable digestibility  fermentable c a r b o h y d r a t e was  K . c a l o r i e s f o r 5 lambs the average  d i g e s t i b i l i t y of  4 3 . 2 7 » .  McLaren e_t a_l  ( 1 9 6 5 )  s t a t e d t h a t sugars d i s a p p e a r too q u i c k l y  from  the rumen w h i l e c e l l u l o s e becomes a v a i l a b l e too s l o w l y to s a t i s f y the energy needs o f microorganisms.  A m i x t u r e o f r e a d i l y a v a i l a b l e and the  more complex s l o w l y a v a i l a b l e c a r b o h y d r a t e s seems s a t i s f a c t o r y . g l u c o s e or s t a r c h i s added, the uptake  o f ammonia by the microorganisms  i s much more r a p i d than when roughage a l o n e i s p r e s e n t . makes the a d d i t i o n o f r e a d i l y  When  I t i s t h i s which  fermentable c a r b o h y d r a t e d e s i r a b l e when  n o n - p r o t e i n n i t r o g e n supplements a r e f e d i n a form i n which l a r g e amounts of ammonia a r e r a p i d l y produced  i n the rumen.  By i n c r e a s i n g  the r a t e o f  u t i l i z a t i o n o f ammonia so t h a t i t more n e a r l y matches the r a t e o f formation,  the c a r b o h y d r a t e reduces  the c o n c e n t r a t i o n o f ammonia i n the  r u m i n a l f l u i d and so d e c r e a s e s the amount l o s t the danger o f t o x i c i t y / ,  from the rumen and l e s s e n s  to the a n i m a l .  Some workers have f e d urea as s a l t / u r e a b l o c k s . ( 1 9 6 5 )  Beames and M o r r i s  s t u d i e d the e f f e c t o f s a l t / u r e a b l o c k s on body-weight, body compos  t i o n and wool p r o d u c t i o n o f merino wethers f e d to a p p e t i t e on l o w - p r o t e i n p a s t u r e g r a s s hay w i t h a crude p r o t e i n content o f  3 . 5 7 o .  The r e s u l t s  i n d i c a t e d t h a t the c o n t r o l group which d i d not have a c c e s s to urea b l o c k s  30. lost s  20%  o f t h e i r i n i t i a l body weight, d u r i n g the t r i a l .  Groups g i v e n  a l t b l o c k s c o n t a i n i n g 20% urea p l u s molasses l o s t 10% of t h e i r i n i t i a l body  weight. of  Those g i v e n b l o c k s c o n t a i n i n g 20% urea and no molasses l o s t  t h e i r i n i t i a l body weight showing t h a t r e a d i l y s o l u b l e sugars  the u t i l i z a t i o n of urea.  syrupiness.  improve  I t shows t h a t molasses serves as a source  energy f o r the microorganisms and  12%  of  causes slow i n t a k e because of i t s s t i c k y  R e s u l t s a l s o i n d i c a t e d t h a t v o l u n t a r y i n t a k e of hay  and  out-  put o f dry m a t t e r i n f a e c e s were i n c r e a s e d by u r e a and weight o f c l e a n soured wool was  g r e a t e r but not s i g n i f i c a n t l y i n groups g i v e n  From comparative g i v e n hay  urea.  s l a u g h t e r , energy r e s e r v e s o f the b o d i e s o f sheep  o n l y were d e p l e t e d to a g r e a t e r e x t e n t than was  i n d i c a t e d by  body weight changes. Urea i n c r e a s e s the net energy v a l u e o f h i g h f i b e r mixtures rations.  C o l o v o s , Keener, D a v i s , Reddy and Reddy (1963) confirmed  statement.  They f e d cows on two  c o n c e n t r a t e mixtures  f i b e r along w i t h e a r l y cut hay. c o n c e n t r a t e mixture  were 1.739  g.  c o n t a i n i n g 10%  These mixtures were f e d alone o r w i t h  c o n t a i n i n g 40 pounds/ton of urea.and s u p p l y i n g 35%  the p r o t e i n o f the c o n c e n t r a t e m i x t u r e . v a l u e s f o r low  the above  e i t h e r w i t h a low  l e v e l of f i b e r c o n t a i n i n g 5% f i b e r or a h i g h f i b e r mixture  to  i n ruminant  K.  the a d d i t i o n of u r e a  c a l o r i e s per g. r e s p e c t i v e l y .  these r a t i o n s the r e s p e c t i v e v a l u e s were 1.806  When u r e a was  and 1.752  K.  added  calories  There were no s i g n i f i c a n t d i f f e r e n c e s i n net energy v a l u e s o b t a i n e d  or without  the a d d i t i o n of u r e a .  I t showed t h a t a f t e r the a d d i t i o n of  the r a t i o n c o n t a i n i n g h i g h f i b e r was fiber. u r e a was  I t was  thought  added i n the  to be due ration.  of  R e s u l t s showed t h a t net energy  f i b e r and h i g h f i b e r r a t i o n s without  and 1.507  a  comparable to the one  to a decrease  i n the h e a t  per with urea  c o n t a i n i n g low increment  where  Oestrogens have been shown to i n c r e a s e the u r e a n i t r o g e n r e t e n t i o n . B e l l , T a y l o r and Murphree (1957) i n v e s t i g a t e d the e f f e c t s diethylstilbestrol  on d i g e s t i b i l i t y and  urea mixture containing lambs a t the  other  no  significant  n u t r i e n t s but  the d a i l y  day.  effect  Results  d i e t h y l s t i l b e s t r o l + urea and r e t e n t i o n of n i t r o g e n was  i n the f a e c e s .  i t was  4.9g.  urea alone,  found to be due  thought to be due  Urea had  no  fed  to  4  mg.  or w i t h  showed that  diethylstilbestrol  and  significantly 3.3g.  effect  daily  respectively.  This  increased  for increased  to a d e c r e a s e i n the amount of  i n the u r i n e . D i e t h y l s t i l b e s t r o l  I t was  was  corn-  on the d i g e s t i b i l i t y of crude p r o t e i n or  i n c r e a s e d phosphorus r e t e n t i o n which i n c r e a s e d the 7 days.  alone  f e e d i n g of d i e t h y l s t i l b e s t r o l  n i t r o g e n r e t e n t i o n and  nitrogen excreted  This ration  pounds per head d a i l y  d i e t h y l s t i l b e s t r o l per head per f e e d i n g had  n u t r i e n t r e t e n t i o n of a  13.57=, crude p r o t e i n .  l e v e l of 1.25  of  feeding  from 0.3  significantly  to 1.3g.  during  to decreased e x c r e t i o n of phosphorus  on the r e t e n t i o n of e i t h e r c a l c i u m  or  phosphorus.  with ing  Karr,  Garrigus,  3 mg.  diethylstilbestrol  1.57» u r e a w i t h  lambs.  Hatfield  and  Norton (1965) showed t h a t lambs  each i n t h e i r  13.17» crude p r o t e i n gained  There were no  significant  on r a t i o n w i t h u r e a and  implanted  with  weight by  the  T h i s was  than the  with  thought to be due  nitrogen.  Lambs  15 pounds i n 21  i t took 54 days to g a i n the same  diethylstilbestrol  and  f e d on  ration  to i n c r e a s e d n i t r o g e n r e t e n t i o n  d i e t h y l s t i l b e s t r o l a l s o markedly reduced the a d a p t a t i o n r e c e i v i n g urea  contain-  unimplanted  feed i n t a k e .  the hormone gained  i n i t i a l weight of 60 pounds but lambs not implanted  faster  f e d on a r a t i o n  differences in daily  days w i t h  with urea.  ear and  implanted  p e r i o d of  lambs  and  32.  Some workers have i n v e s t i g a t e d the r e l a t i o n s h i p of sulphur Thomas, L o o s l i , W i l l i a m s and Maynard  ( 1 9 5 1 )  and  urea.  s t a t e d t h a t an adequate  o f sulphur i s r e q u i r e d f o r i n c o r p o r a t i o n of ammonia i n t o methionine  as MgS0^(204g.) and MnS0^(3g.) or urea w i t h o u t showed t h a t lambs d i d not weight d u r i n g sulphate  the f i r s t  those on sulphur  daily  l o s s was  60 days of the t r i a l .  f e d urea  to l o s e weight and  Gallup  reported  ( 1 9 5 5 )  t h a t methionine and  their  urea  added  crude p r o t e i n ) b a s a l r a t i o n f o r f a t t e n i n g  ( 8 . 4 7 ,  but  the i n c r e a s e s were not  Poor performance of lambs g i v e n urea a l o n e to the d e f i c i e n c y of sulphur of 0.1%.  supplements i n the urea of m e t h i o n i n e .  they  statisti-  They f u r t h e r s t a t e d that soybean meal as a supplement  the b a s a l r a t i o n c o n s i s t e n t l y improved r a t e of g a i n and  content  +  34g.  to improve the r a t e of g a i n but when added i n combination  significant.  sulphur  those  t h e i r average d a i l y g a i n was  i n c r e a s e d the d a i l y g a i n i n each t r i a l  p a r t l y due  results  they a l l l o s t  Thereafter  d e f i c i e n t feed c o n t i n u e d  s e p a r a t e l y to a low p r o t e i n  to  Their  sulphur  70g.  Noble, Pope and  lambs f a i l e d  sulphur.  eat p u r i f i e d d i e t s r e a d i l y and  i n c r e a s e d i n body weight and  while  cally  and  They f e d lambs on p u r i f i e d d i e t s c o n t a i n i n g 4 7 « urea and  cysteine.  supply  The  nitrogen:  r a t i o n was  feed  to the b a s a l r a t i o n  was  i n the b a s a l r a t i o n which had sulphur  r a t i o o f the  the a d d i t i o n  gain.  showed t h a t soybean meal  was  a s i g n i f i c a n t l y b e t t e r p r o t e i n supplement f o r lambs than u r e a when urea  was  fed  a t the r a t e o f t h r e e p e r c e n t  Bolin  a  nitrogen  narrowed from 5 9 : 1 to 1 5 : 1 by  T h i s f a c t o r c o n t r i b u t e d to the improved d a i l y  L i g h t , Dinusson, R i c h a r d and  efficiency.  ( 1 9 5 7 )  of the c o n c e n t r a t e m i x t u r e and  4 1 7 o of n i t r o g e n i n the r a t i o n , w i t h poor q u a l i t y non-legume hay ad-libitum.  supplying fed  33.  Soybean meal i s a b e t t e r source o f n i t r o g e n than u r e a . Loosli  (1961) conducted  D r o r i and  experiments with'sheep and showed t h a t the d i e t  w i t h soybean meal gave b e t t e r n i t r o g e n r e t e n t i o n and had a h i g h e r b i o l o g i c a l v a l u e than d i e t s w i t h u r e a .  T h i s f i n d i n g was thought  r e l a t e d t o the e x c r e t i o n o f urea i n the u r i n e .  to be  They a l s o showed t h a t  urea n i t r o g e n i n b l o o d r o s e a f t e r d i e t s w i t h urea and f e l l a f t e r w i t h soybean meal but t h e d i f f e r e n c e s were not s i g n i f i c a n t . s t a t e d t h a t b l o o d urea  diets  They f u r t h e r  l e v e l s i n t h i s study were n o t c o n s t a n t and the  average l e v e l s o f b l o o d urea gave no c l u e t o the v a l u e o f p r o t e i n i n the feed.  They gave the r e a s o n  paired.  t h a t the d a t a i n t h e i r experiment was not  They f u r t h e r showed t h a t urea produced a sharp r i s e i n rumen  ammonia o n l y when g i v e n r a p i d l y through P r e s t o n , Schnakenberg and Pfander find  the f i s t u l a . (1965) conducted  experiments t o  the e f f e c t o f p r o t e i n i n t a k e on b l o o d urea n i t r o g e n i n lambs f e d to  a p p e t i t e on f i n i s h i n g r a t i o n s c o n s i s t i n g o f soybean meal and c o r n w i t h d i f f e r e n t crude p r o t e i n c o n t e n t s  (9.2, 11.5, 13.1, 16.5 and 22.0%).  R e s u l t s i n d i c a t e d that the d a i l y g a i n , f e e d i n t a k e , urea n i t r o g e n i n b l o o d and d i g e s t i b i l i t i e s o f energy and p r o t e i n i n c r e a s e d when there was more p r o t e i n i n the f e e d and e f f i c i e n c y o f f e e d c o n v e r s i o n improved  also.  The r e s u l t s a l s o showed t h a t the v a r i a t i o n i n the p r o t e i n i n t a k e o f the growing lamb r e s u l t e d i n b l o o d urea n i t r o g e n (BUN) r a n g i n g S.mg./100 ml.  from 2.7 to 3.29  They s t a t e d t h a t the p r o t e i n s t a t u s o f the lamb can be  a s s e s s e d p a r t i a l l y by the c o n c e n t r a t i o n o f t h i s b l o o d c o n s t i t u e n t .  In  terms o f p r o t e i n adequacy a BUN v a l u e i n excess o f lOmg./lOO m l . would i n d i c a t e adequate p r o t e i n i n t a k e w i t h the type o f r a t i o n s f e d i n these experiments.  I n another  experiment urea was used as a supplemental  o f n i t r o g e n (47%, o f t o t a l n i t r o g e n ) f o r lambs.  source  They consumed 16g. p r o t e i n /  . 34.  W ° * ^ where W=live weight i n pounds. T h i s BUN  i s higher  T h e i r average BUN  than the l e v e l o b t a i n e d  was  27.3  mg./lOO ml.  w i t h soybean meal and  corn.  They r e l a t e d t h i s to a lower b i o l o g i c a l v a l u e of u r e a , when f e d at  this  level. O l i v i e r a n d Cronje  (1964) s t u d i e d the e f f e c t of the r a t e of i n t a k e  u r e a upon the n i t r o g e n r e t e n t i o n of sheep.  Special urea-containing  of  pills  which r e l e a s e d the u r e a g r a d u a l l y over a 24 hour p e r i o d were developed. One  group r e c e i v e d a dose of 8 g. u r e a d a i l y , the o t h e r  pill  c o n t a i n i n g 8 g. u r e a w h i l e  p r o t e i n n i t r o g e n content 8 hours a f t e r d o s i n g .  the t h i r d group r e c e i v e d no u r e a .  of the b l o o d  The  group r e c e i v e d  of sheep was  determined 1.5,  group which r e c e i v e d the u r e a i n p i l l  Urea supplementation had  no  The  non-  3.5  and  form  r e t a i n e d s i g n i f i c a n t l y more n i t r o g e n than the group which r e c e i v e d normal dose of u r e a d a i l y .  the  e f f e c t on  one crude  fiber digestion. Many workers have i n v e s t i g a t e d the e f f e c t s of d u o d e n a l l y urea.  Egan (1965) conducted v a r i o u s experiments to f i n d the f a t e of duo-  denally infused casein  (71 g.)  i n sheep f e d on oaten hay ing  9%  crude p r o t e i n .  p r o v i d i n g 10 g. of  nitrogen  ( i n c l u d i n g s e e d s ) , molasses and m i n e r a l s  contain-  Results  and u r e a (22 g.)  showed t h a t the u r e a i n the b l o o d  ammonia n i t r o g e n i n rumen were i n c r e a s e d by d u o d e n a l l y casein. lose  infused  Both sources of n i t r o g e n i n c r e a s e d  ( c o t t o n thread) and  c a s e i n . , Peak v a l u e s hours l a t e r . excreted  the peak was  i n f u s e d urea  and  the r a t e of d i g e s t i o n of  cell-  reached e a r l i e r a f t e r u r e a than a f t e r  f o r both occured between the end  Of the n i t r o g e n supd-ied  and  of i n f u s i o n and  by these sources more n i t r o g e n  i n the u r i n e a f t e r u r e a than a f t e r c a s e i n .  Results  of  six was  this  i n v e s t i g a t i o n c l e a r l y demonstrated the r e t u r n of n i t r o g e n to rumen a f t e r i n f u s i o n per duodenum of s i n g l e doses of e i t h e r c a s e i n or u r e a as both  35.  ruminal  ammonia n i t r o g e n c o n c e n t r a t i o n s  and the r a t e o f c e l l u l o s e d i g e s -  t i o n ( c o t t o n thread) i n the rumen were i n c r e a s e d . the rumen a f t e r a b s o r p t i o n  Return of nitrogen to  r a t h e r than by back-flow from the duodenum  through both abomasum and omasum was suggested by the f o l l o w i n g o b s e r v a tions. 1)  Maximum r u m i n a l  ammonia n i t r o g e n c o n c e n t r a t i o n s  were much  lower when c a s e i n was g i v e n than when urea was g i v e n . 2)  Ruminal ammonia n i t r o g e n c o n c e n t r a t i o n s  d i d not r i s e  until  a f t e r c o m p l e t i o n o f the i n f u s i o n o f c a s e i n . 3)  The time and magnitude o f r u m i n a l reflected nitrogen  The A  ammonia n i t r o g e n changes  the time and magnitude o f changes i n b l o o d  urea  concentration.  b l o o d u r e a n i t r o g e n l e v e l i n c r e a s e d r a p i d l y as u r e a was i n f u s e d .  l e s s r a p i d i n c r e a s e i n the b l o o d u r e a n i t r o g e n  c a s e i n was g i v e n .  l e v e l was r e c o r d e d  A f t e r i n f u s i o n of casein neither  l e v e l nor the r u m i n a l  the b l o o d u r e a  when nitrogen  ammonia n i t r o g e n c o n c e n t r a t i o n were r a i s e d to the  same e x t e n t as when u r e a was g i v e n which suggested t h a t l e s s n i t r o g e n was returned  to rumen a f t e r c a s e i n i n f u s i o n .  Egan and M o i r (1965) i n v e s t i g a t e d the e f f e c t s o f duodenally s i n g l e doses o f c a s e i n and u r e a (4.5g.N/day)on v o l u n t a r y p r o t e i n roughage by sheep.  Results  infused  i n t a k e o f a low-  showed t h a t the c a s e i n and u r e a gave  s i g n i f i c a n t but t r a n s i e n t i n c r e a s e s i n v o l u n t a r y  i n t a k e o f f e e d , c a s e i n on  the day i t was g i v e n and u r e a on the day a f t e r . Egan (1965) conducted another experiment to f i n d  the i n f l u e n c e o f  s u s t a i n e d duodenal i n f u s i o n s o f c a s e i n or urea upon v o l u n t a r y low-protein  roughages by sheep.  The r e s u l t s r e v e a l e d  mean d a i l y i n t a k e o f d r y matter was 12% and w i t h  intake of  t h a t w i t h u r e a the  c a s e i n 42%, g r e a t e r  than  36. that observed with the control group.  It showed that when nitrogen balance  was improved and the amount of amino acids absorbed was increased, the intake of dry matter increased, Results also showed that the apparent digestibility of dry matter was decreased consistently though not significantly by casein but urea had no consistent effect.  The depressed digestibility of  dry matter i n case of casein was due to greater dry matter intake.  I t was  also shown that the volume of rumen f l u i d was significantly increased by casein but urea had no effect.  Nitrogen balance results showed that i t was  negative i n controls but became positive with either casein or urea.  Nitrogen  content of faeces was not affected but urea though consistently but not significantly increased excretion of nitrogen i n the urine.  V.  EFFECT OF FEED UREA ON MILK YIELD AND  E f f e c t On M i l k  The  MILK COMPOSITION  Production  problem of r e p l a c i n g p r o t e i n s , as the main n a t u r a l  nitrogen i n feeding milk-producing  ruminants, by  sourceof  the a d d i t i o n of urea  the feed o f these animals, i s o f i n t e r e s t not o n l y from s c i e n t i f i c a l s o from the economic p o i n t of view.  but  T h i s i s because n i t r o g e n i s much  cheaper i f s u p p l i e d i n the form of u r e a , w h i l e most expensive c o n s t i t u e n t s o f c o n v e n t i o n a l p r o d u c t i o n would be c o n s i d e r a b l y  p r o t e i n s a r e among  rations.  The  the  cost of  milk  lower i f a t l e a s t some p a r t of the neces-  sary p r o t e i n s c o u l d be r e p l a c e d by a cheaper s y n t h e t i c p r o d u c t l i k e Urea and  other  non-protein  i n milk production. f i r s t pointed  ( 1 9 6 7 )  Schoenemann  compounds have been shown to be ( 1 9 4 6 )  257o  used N ^  ( 1 9 6 7 )  and K i l i a n  utilized  c i t e d by  ( 1 9 4 8 )  urea.  Briggs  out t h a t u r e a l a b e l l e d w i t h N"*""* added to the f e e d s t u f f  became a component of m i l k i n g o a t s . Briggs  to  Land and  Virtanen  ( 1 9 5 9 )  i n the form of ammonium s a l t s and  o f t h i s n i t r o g e n appeared i n m i l k .  cited  found t h a t  by to  17  They showed t h a t the p r o c e s s  of  i n c o r p o r a t i o n o f l a b e l l e d ammonium n i t r o g e n i s most i n t e n s i v e 1 4 hours a f t e r f e e d i n g , and glutamic  a f f e c t s the amine n i t r o g e n f r a c t i o n s of such amino a c i d s  a c i d , a s p a r a g i n e and  alanine.  They f u r t h e r showed t h a t a f t e r 2 4  hours the amino a c i d s i n the m i l k p r o t e i n are a l r e a d y more u n i f o r m l y except f o r h i s t i d i n e and  as  c y s t i n e , which show a c o m p a r a t i v e l y  low  labelled,  percentage  1 5  of N  .  They a l s o c a l c u l a t e d t h a t on the whole about  n i t r o g e n s u p p l i e d i s taken up by The  been m o s t l y i n v e s t i g a t e d i n d a i r y cows and sheep.  o f the  labelled  the t i s s u e p r o t e i n .  e f f e c t o f feed u r e a on m i l k p r o d u c t i o n  i n the case o f  407o  and m i l k c o m p o s i t i o n  l i t t l e work has  has  been c a r r i e d out  38.  Rust, L a s s i t e r , D a v i s , Brown and urea and  dicyandiamide  t r a t e mixture  Seath  (1956) e v a l u a t e d soybean meal,  as n i t r o g e n sources i n low p r o t e i n (13.1%) concen-  f o r d a i r y cows.  Each n i t r o g e n source s u p p l i e d one  the n i t r o g e n i n the c o n c e n t r a t e m i x t u r e and each cow medium q u a l i t y age.  timothy hay  per 100  lactation.  The average  196 days p e r i o d was cow  daily  35.3  of  d a i l y m i l k p r o d u c t i o n a t the b e g i n n i n g and end and  18.5,  The d i f f e r e n c e s were s i g n i f i c a n t .  35.9  and  14.4;  and 36.2  Hay  and  rations,  15.5  of  l b . per  respectively.  Minor d i f f e r e n c e s i n f e e d consumption  consumption was  d a i l y and c o n c e n t r a t e consumption was the t h r e e groups,  on a l a c t a t i o n b a s i s or  days i n l e n g t h b e g i n n i n g 30th day  f o r soybean meal, urea and dicyandiamide  e x i s t e d between groups.  pounds of  l b . body weight d a i l y as the o n l y rough-  D i f f e r e n c e s i n m i l k p r o d u c t i o n were observed  d u r i n g a comparison p e r i o d of 196  r e c e i v e d two  t h i r d of  11.9,  18.5, 10.8  18.0  and  and  11.5  16.8  lb./cow  lb./cow d a i l y f o r  respectively.  Owen, Smith and Wright  (1943) p o i n t e d out i n t h e i r b a l a n c e  experiments  on d a i r y cows t h a t when urea and b l o o d meal r e p l a c e d 257, of the n i t r o g e n i n a r a t i o n no d i f f e r e n c e s i n m i l k p r o d u c t i o n or i n n i t r o g e n b a l a n c e were shown f o r many weeks.  They a l s o i n d i c a t e d t h a t when urea was  i n m i l k p r o d u c t i o n occured  withdrawn a  decrease  immediately.  H a s t i n g s (1944) r e p l a c e d maize g l u t e i n i n a c o n c e n t r a t e by urea which s u p p l i e d 257, i n the b e g i n n i n g and 437. of the t o t a l n i t r o g e n i n the end of experiment t r a t e was  i n the r a t i o n o f d a i r y cows. 20.67..  urea r a t i o n was  The p r o t e i n c o n t e n t of the concen-  R e s u l t s showed t h a t the average m i l k y i e l d when u s i n g  g r e a t e r than i n c o n t r o l  this  ration.  Many workers have shown t h a t urea i s poor f o r m i l k p r o d u c t i o n as compared to soybean meal.  the  3 9 .  B a r t l e t t a n d B l a x t e r (1947) emphasized t h a t any p r o t e i n s p a r i n g e f f e c t of urea or o t h e r sources of n o n - p r o t e i n n i t r o g e n can o n l y be determined animals f e d p r o t e i n d e f i c i e n t r a t i o n s . by i n c r e a s i n g the percentage 17.9,  The a d d i t i o n o f p r o t e i n to such a r a t i o n  o f crude p r o t e i n i n the r a t i o n from 12.9  resulted i n a s i g n i f i c a n t increase i n milk production.  the p r o t e i n d e f i c i e n c y o f the l o w p r o t e i n r a t i o n . i t i o n of s u f f i c i e n t urea p r o t e i n to  17.97o,  to  This confirmed  They s t a t e d t h a t the add-  to such a low p r o t e i n r a t i o n to i n c r e a s e the  crude  t h a t i s the a d d i t i o n of the same amount o f n i t r o g e n as  urea as had been added as p r o t e i n , r e s u l t e d i n no in milk production.  When u r e a was  crude p r o t e i n ) a d e c l i n e i n y i e l d cally  in  s i g n i f i c a n t mean change  added to a normal p r o t e i n r a t i o n (17.97° occured.  T h i s was  however not  statisti-  significant. Ward, Huffman and Duncan (1955) f e d cows a c o n c e n t r a t e c o n t a i n i n g about  1 5 7 o of soybean meal or 2 7 o o f urea b e s i d e s b a s i c f e e d s . m i l k p r o d u c t i o n i n F.C.M. ( f a f c o r r e c t e d m i l k ) was  R e s u l t s showed t h a t  not s i g n i f i c a n t l y  ent when cows were on c o n c e n t r a t e w i t h soybean meal or u r e a . was  27.6  and 28.2  lb./day f o r urea and  O t a g a k i , Wayman, M o r i t a and  and  F.C.M. produced respectively.  Iwanaga (1956) f e d the cows a r a t i o n i n  which 217., o f n i t r o g e n requirement was there was  soybean meal r a t i o n s ,  differ-  s u p p l i e d by u r e a .  R e s u l t s showed t h a t  no s t a t i s t i c a l d i f f e r e n c e i n m i l k p r o d u c t i o n between the c o n t r o l  the other  group.  E f f e c t of u r e a on m i l k p r o d u c t i o n , f e d as a spray on hay, has a l s o been studied.  P a l l a n and P e j o V i c (1965) f e d sheep d u r i n g w i n t e r on hay  sprayed w i t h  u r e a s o l u t i o n a t the r a t e o f 0.25kg. u r e a i n 2 l i t e r s of water on the days r a t i o n f o r 20 sheep. urea m a i n t a i n e d were p o o r e r . weight.  R e s u l t s of t h e i r experiment  t h e i r body weight  The c o n t r o l s who  showed that the ewes g i v e n  but m i l k y i e l d s f o r the firs'tefl.O'eek p e r i o d  a t e 0 . 3 to 1.5kg. hay  d a i l y w i t h o u t urea  lost  40.  Some workers have compared urea w i t h other NPN  sources f o r m i l k p r o -  duction. Loskutov  and B e r k o r i c (1965) s t u d i e d the e f f e c t of 257, o f d i g e s t i b l e  p r o t e i n p r o v i d e d f o r p r o l o n g e d p e r i o d s by urea (90g. d a i l y ) and  ammonia  s o l u t i o n (225ml. d a i l y ) on m i l k p r o d u c t i o n and m i l k c o m p o s i t i o n of cows. R e s u l t s showed t h a t cows g i v e n urea had  somewhat g r e a t e r p h a g o c y t i c  activity  of b l o o d and h i g h e r g l o b u l i n v a l u e s than the o t h e r s and a l s o gave more m i l k throughout  the l a c t a t i o n p e r i o d w i t h h i g h e r c o n t e n t s of f a t , p r o t e i n  and  casein. Waite, C a s t l e , Watson and D r y s d a l e (1968) conducted  an experiment  to  compare the f e e d i n g v a l u e of c o n c e n t r a t e s f o r m i l k p r o d u c t i o n i n which n i t r o g e n normally b i u r e t or u r e a .  s u p p l i e d by o i l cake was Each cow  c o m p l e t e l y r e p l a c e d by  the  either  had been m i l k i n g f o r 70 days b e f o r e the e x p e r i -  ment s t a r t e d .  Urea or b i u r e t c o n t r i b u t e d 527, of the t o t a l n i t r o g e n i n the  concentrates.  Hay was  f e d as the s o l e roughage.  t o t a l n i t r o g e n on dry matter 4 lb./10 l b . m i l k . urea and b i u r e t day was  basis.  C o n c e n t r a t e s had  C o n c e n t r a t e s were f e d a t the r a t e of  R e s u l t s showed t h a t m i l k p r o d u c t i o n was  treatments  than on the c o n t r o l .  Milk yield  107> l e s s  on  i n pounds/cow/  25.5,  23.0  and 22.8  -0.5,-0.6 and  -0.5  f o r c o n t r o l , b i u r e t and urea r a t i o n s , r e s p e c t i v e l y .  dry matter  and  l i v e weight change i n pounds/cow/day  i n t a k e (hay + c o n c e n t r a t e ) was  respectively 9.5  and  3.1%  9.0  f o r the t h r e e treatments. lb./cow d a i l y  23.4,  23.1  and  22.4  was  lb./cow/day,  Intake of the c o n c e n t r a t e s was  f o r the t h r e e groups.  Total  The percentages  9.7,  of f a t and  p r o t e i n i n the m i l k from urea and b i u r e t treatments were h i g h e r than from control.  T h i s was  due  of f a t i n the m i l k was 3.10,  3.16  and  to low m i l k y i e l d i n the former 4.05,  4.45  and 4.377. and  treatments.  Percentage  t h a t o f crude p r o t e i n  3.197, f o r c o n t r o l , b i u r e t and urea treatments,  the  was  respectively.  41.  Urea has been f e d s e p a r a t e l y a l o n g w i t h used urea Van  Some workers have  treated silage. Horn, Jacobson  ground s h e l l e d c o r n . and  silage.  and Gradten  One  (1969) f e d cows on c o r n s i l a g e  group was  g i v e n added u r e a a t the l e v e l of 423g.  the other group a t the l e v e l of 81g. urea/cow d a i l y .  c o n t e n t of both  the r a t i o n s was  and  Crude p r o t e i n  the same (13.57<> on dry matter  basis).  R e s u l t s showed t h a t m i l k p r o d u c t i o n and weight g a i n s were lower on h i g h urea than low u r e a r a t i o n . was  34.2  Feed i n t a k e f o r the low u r e a and h i g h urea  and 33.8kg. and m i l k p r o d u c t i o n was  25.9  and 23.4kg. d a i l y ,  ration  respec-  tively . Van Horn, H o c r a f f e r and Foreman (1969) conducted the m i l k p r o d u c t i o n responses the f i r s t experiment cantly  experiments  from u r e a t r e a t e d c o r n s i l a g e .  to f i n d  R e s u l t s of  showed t h a t l a c t a t i n g 'Holstein cows produced  l e s s m i l k when r e c e i v i n g urea i n h i g h - d r y matter  signifi-  c o r n s i l a g e a t the  l e v e l of 0.57 as compared to the p r o d u c t i o n when cows r e c e i v e d soybean meal 0  as the o n l y n i t r o g e n supplement. between r e s p e c t i v e dry matter per cow  daily  experiment  and  kg. per cow  M i l k y i e l d s i n Kg.  and  20.5kg. d u r i n g the  and  26.4  experimental  and 0.39kg./cow d a i l y f o r  respectively.  l a c t a t i n g H o l s t e i n cows r e c e i v i n g 31.97 dry  urea t r e a t e d s i l a g e produced dry matter  23.2  Body weight g a i n s were 0.44  soybean meal r a t i o n ,  In another  were 26.7  f a t percentage.  observed  f o r soybean meal and urea supplemented cows were 26.9  period, respectively.  46.27o  s i g n i f i c a n t d i f f e r e n c e s were  i n t a k e s and  kg. f o r the p r e l i m i n a r y p e r i o d and  u r e a and  No  matter  0  s i g n i f i c a n t l y more m i l k than cows r e c e i v i n g  urea treated s i l a g e .  Their preliminary period milk y i e l d s  26.8kg. and e x p e r i m e n t a l p e r i o d m i l k y i e l d s were 22.7  daily, respectively.  They concluded  t r e a t e d s i l a g e i s not s a t i s f a c t o r y as lower  and  t h a t h i g h dry matter  dry matter  20.6  urea  urea t r e a t e d s i l a g e  42.  for  l a c t a t i n g d a i r y cows.  The d i g e s t i b i l i t y dry matter  The f e e d i n t a k e was  s i m i l a r i n both the c a s e s .  and r e t e n t i o n o f absorbed n i t r o g e n was  lower f o r the h i g h  urea t r e a t e d s i l a g e which r e s u l t e d i n lower m i l k p r o d u c t i o n .  Solovev, Manenkova and B e l o v a (1966) s t u d i e d the e f f e c t of u r e a i n the f e e d o f cows on,the q u a l i t y o f m i l k who were g i v e n u r e a to r e p l a c e 357, o f the d i g e s t i b l e crude p r o t e i n o f the r a t i o n . i n m i l k i n c r e a s e d but t h e r e was l i t t l e Van Horn, Foreman and Rodriguez 14.97, crude p r o t e i n . and  Results i n d i c a t e d that urea  change i n t o t a l  protein.  (1967) f e d cows a r a t i o n c o n t a i n i n g  Each cow was o f f e r e d 4.6kg. hay, 18.2kg. c o r n  18.2kg. o f c o n c e n t r a t e d a i l y .  silage  A d d i t i o n o f 2.77, u r e a to the c o n c e n t r a t e  mixture r e s u l t e d i n s i g n i f i c a n t d e p r e s s i o n of f e e d i n t a k e but t h e r e was no i n t e r a c t i o n between u r e a and c o r n s i l a g e . thought  to be due to depressed  D e p r e s s i o n i n m i l k p r o d u c t i o n was  feed i n t a k e .  The depressed  feed i n t a k e s were  4.4kg. hay, 17.0kg. c o r n s i l a g e and 7.8kg. c o n c e n t r a t e d a i l y .  M i l k produc-  t i o n w i t h u r e a was 22.0kg./day as compared to 26.4kg./day w i t h o u t Colovos, H o l t e r , D a v i s and Urban,Jr. r a t i o n c o n t a i n i n g 17.27, crude p r o t e i n . 1.25, 2.0 or 2.57, u r e a  urea.  (1967) f e d l a c t a t i n g cows on a  A c o n c e n t r a t e mixture  c o n t a i n i n g 0.0,  (427, N) was f e d i n p l a c e of an e q u i v a l e n t amount o f  p l a n t p r o t e i n n i t r o g e n , w i t h good q u a l i t y  timothy hay.  There were no  i c a n t d i f f e r e n c e s i n m i l k p r o d u c t i o n or c o m p o s i t i o n or i n r a t i o n  signif-  digestibility.  P r o t e i n b a l a n c e was p o s i t i v e i n a l l treatments. Rohr (1962) as c i t e d by B r i g g s (1967) s t u d i e d the i n f l u e n c e o f a h i g h p r o p o r t i o n o f c e l l u l o s e i n d a i r y cow r a t i o n s . and  I n h i s experiments  i n vivo  i n v i t r o he found t h a t a l a r g e amount of f i b e r i n the r a t i o n l e a d s to a  marked r e d u c t i o n i n the number o f microorganisms rumen.  The m i c r o f l o r a o r i g i n a t i n g under these c o n d i t i o n s , i n s p i t e of i t s  lower number, has a g r e a t e r urease a c t i v i t y organism  i n the c o n t e n t s o f the  than a more numerous m i c r o r  p o p u l a t i o n when g i v e n s t a r c h f e e d s t u f f .  A l a r g e amout of f i b e r and  4 3 .  the r e s u l t a n t easy and r a p i d decomposition of u r e a i n t o ammonium n i t r o g e n causes a r i s e i n the p'H i n the rumen which i n c r e a s e s the p e r m e a b i l i t y o f the w a l l o f the rumen.  T h i s consequently l e a d s to an i n c r e a s e i n the  loss  of ammonium n i t r o g e n as a r e s u l t o f i t s e n t r y i n t o the b l o o d c i r c u l a t i o n . However, he i n d i c a t e s f u r t h e r t h a t urea w e l l mixed w i t h the r a t i o n ,  ensur-  i n g a c o n s t a n t r e g u l a r supply o f u r e a to the rumen, l e a d s to good u r e a u t i l i z a t i o n and m a i n t a i n s a h i g h m i l k p r o d u c t i o n even when the r a t i o n tains a relatively comparing  l a r g e amount o f crude f i b e r .  He  the i n f l u e n c e o f an a d d i t i o n o f soybean  deficient i n protein.  demonstrated  con-  t h i s by  bran or u r e a to a r a t i o n  When cows were f e d r a t i o n d e f i c i e n t i n p r o t e i n w i t h  a l a r g e f i b e r c o n t e n t , the a d d i t i o n o f u r e a w e l l mixed w i t h the r a t i o n mass caused an i n c r e a s e i n the number o f rumen microorganisms as soybean bjran. to a c i d i t y  to the same degree  T h i s i n t u r n l e d to b e t t e r d i g e s t i o n of the f i b e r ,  then  of the rumen a r e a , and by t h i s to an improvement i n the urea  u t i l i z a t i o n i n the rumen. E f f e c t s o f l e v e l s o f f i b e r i n the c o n c e n t r a t e m i x t u r e and the e f f e c t of u r e a , on m i l k p r o d u c t i o n has been f u r t h e r  investigated.  Colovos et. a l (1967) used il£>lstein cows, i n the second months o f t h e i r  lactation,  through  to study the e f f e c t o f c o n c e n t r a t e f i b e r  u r e a on r a t i o n u t i l i z a t i o n and p r o d u c t i o n .  fifth and  Crude p r o t e i n c o n t e n t o f the  c o n c e n t r a t e m i x t u r e was  16.77<». Body weight o f the f o u r animals used a t the  b e g i n n i n g o f experiment  ranged  was  between 20 and 23kg.  from 400  to 500kg.. and d a i l y m i l k p r o d u c t i o n :  C o n c e n t r a t e m i x t u r e s c o n t a i n i n g c o r n meal, oat  meal f e e d , brewer's g r a i n s , molasses, a c c o r d i n g to m i l k p r o d u c t i o n .  soybean meal and m i n e r a l s were f e d  L e v e l s of urea  (427o  N)  i n the c o n c e n t r a t e  m i x t u r e were 0 and 27« and the l e v e l s of f i b e r were 5 and 8 7 c timothy hay was  Fair  quality  f e d as the o n l y f o r a g e a t the r a t e o f 27» o f body w e i g h t .  44. Only minor differences occured i n r a t i o n i n t a k e , p r o t e i n d i g e s t i b i l i t y and m i l k production.  The higher l e v e l s of concentrate f i b e r and urea s l i g h t l y  depressed a c t u a l milk production.  Average 47, FCM (fat corrected milk)  production was 16.30 and 15.78kg. for 57, and 87, f i b e r and 16.3 and 15.75kg./ day for 0 and 2.07. urea, r e s p e c t i v e l y .  High l e v e l s of concentrate f i b e r  and urea s i g n i f i c a n t l y depressed r a t i o n d i g e s t i b i l i t y .  Dry matter, energy  and p r o t e i n intake were not s i g n i f i c a n t l y affected by treatments.  Ration  p r o t e i n d i g e s t i b i l i t y was 66.6 and 65.47, w i t h 5 and 87. f i b e r and 65.6 and 66.47, with 0 and 2.07. urea i n the concentrate,  respectively.  Urea s i g n i f -  i c a n t l y improved the d i g e s t i b i l i t y of f i b e r i n the r a t i o n when included i n the low f i b e r concentrate mixture but had the opposite effect i n high f i b e r concentrate.  They a t t r i b u t e d t h i s to higher intake of f i b e r .  The  l e v e l of urea i n m i l k under various conditions of feeding, has also been investigated. The N a t i o n a l Research Council (1953) i n d i c a t e d that cows normal milk contains from 10. to 60mg»n3?ea/lOOuml.i. Briggs and Hogg (1964) studied the effect of d i e t a r y urea on the l e v e l in milk.  One group of cows was fed a conventional r a t i o n which included a  p r o t e i n supplement.  The second group received a d a i l y average of 3 l b . per  head of urea feed (107, urea i n molasses with added minerals and v i t a m i n s ) . I n d i v i d u a l s showed s i g n i f i c a n t v a r i a t i o n s i n the m i l k urea l e v e l from day to day which were independent of milk y i e l d . milk urea was from 15 to 4S4)mg./100 m l .  In cows given urea the range i n  In cows fed the conventional r a t i o n  i n c l u d i n g p r o t e i n supplement the range was from 3j3; to 58 mg./100ml.  The  differences between the two groups were not s i g n i f i c a n t . Urea feeding has been shown to exert no influence on m i l k composition or f l a v o u r .  V i r t a n e n (1966) studied the effect of feeding urea on milk  45.  composition i n l a c t a t i n g t e s t m i l k was s i m i l a r  cows.  Results  to that o f normal  showed t h a t the c o m p o s i t i o n o f the milk.  ^ F r a c t i o n a t i o n , o f c a s e i n and serum p r o t e i n s o f the t e s t m i l k and normal m i l k by d i f f e r e n t methods showed the s i m i l a r i t y o f the p r o t e i n s of the two milks. similar.  He f u r t h e r s t a t e d t h a t the f l a v o u r s o f the two m i l k s was a l s o  46.  VI.  Experiment No.  EXPERIMENTAL  I  Animals Used T h i r t y bred ewes, b e l o n g i n g to The U n i v e r s i t y of B r i t i s h were used f o r t h i s study d u r i n g t a i n e d a t the sheep u n i t .  the s e s s i o n of 1967-68.  I I two ewes d i d not  Ewes were main-  Ewes were d i v i d e d e q u a l l y i n t o two groups on  the b a s i s of weight, breed and age. Group  Columbia,  In Group I a l l ewes lambed.  In  lamb.  Feeding Both groups of ewes r e c e i v e d d i g e s t i b l e crude p r o t e i n  the same amount of p r o t e i n 90g.(0.21b.)  (D.C.P.)/head/day)  pregnancy and 225g. (0.51b.) D.C.P. d u r i n g Energy  (D.E.) requirement was  during  the l a s t s i x weeks of  lactation.  Their Digestible  s u p p l i e d as f o l l o w s .  D u r i n g l a s t 6 weeks of pregnancy  During l a c t a t i o n  Group I  Maintenance + 50%  Maintenance +  150%  Group  Maintenance + 100%  Maintenance +  100%  II  The above mentioned amount of p r o t e i n and energy was groups by v a r i o u s dairy pellets,  supplied  to both  amounts of brome hay, a l f a l f a hay, beet pulp and, or  as indicated below! -  47. Energy L e v e l s and Feed Supply - Per Head Per Day  Group I (Pregnancy)  Group I I (Pregnancy)  Group I (Lactation)  Group I I (Lactation)  Brome hay (Kg)  Beet p u l p (Kg)  ' Livie weight (Kg)  Required Digestible Energy (K.Calories)  55 60 65 70 75  3000 3200 3400 3600 3800  1.36 1.45 1.54 1.63 1.72  X  55 60 65 70 75  4100 4400 4700 4900 5100  0.72 0.77 0.81 0.86 0.90  0.81 0.86 0.90 0.95 1.00  55 60 65 70 75  5200 5700 6000 6200 .6500  0.68 0.77 0.81 . 0.86 0.90  55 60 65 70 75  .4100 . 4400 4700 4900 5100  1.40 1.45 1.50 1.54 1.59  D a i r y pe! (Kg)  X  X  1.13 1.22 1.27 1.31 1.36  X  0.31 0.36 0.40 0.45 0.50  48. The  composition o f t h e r a t i o n s i s g i v e n i n T a b l e A l .  A l l ewes were  weighed 7 weeks b e f o r e p a r t u r i t i o n , p r e - p a r t urn, post-partum  and t h e n  every  week d u r i n g l a c t a t i o n . M i l k i n g o f Ewes and A n a l y s i s o f M i l k Samples Three ewes from each group were used f o r hand m i l k i n g .  Ewes were  g i v e n an i n j e c t i o n o f an o x y t o c i n i c p r e p a r a t i o n i n t h e morning and  their  udders were emptied  from  by hand m i l k i n g .  The lambs were kept  separate  the ewes i n t h e a d j o i n i n g pen where ewes c o u l d see t h e lambs.  After four  hours t h e ewes were a g a i n g i v e n an i n j e c t i o n o f t h e o x y t o c i n i c p r e p a r a t i o n and immediately cages.  The  hand m i l k e d a f t e r k e e p i n g them secure i n t h e metabolism  q u a n t i t y o f m i l k o b t a i n e d f o r f o u r hours was  t o t a l amount of m i l k produced  d u r i n g 24  hours was  measured and  determined.  the  Samples  were o b t a i n e d a f t e r thorough m i x i n g o f t h e m i l k and were r e t a i n e d f o r the a n a l y s i s o f f a t , p r o t e i n , l a c t o s e , t o t a l s o l i d s and brought  back t o t h e l a b o r a t o r y and kept  ash.  o v e r n i g h t under  A l l samples were refrigeration.  Samples were a n a l y z e d i n the morning i n t h e P r o v i n c i a l Government D a i r y Branch L a b o r a t o r y by i n f r a red m i l k a n a l y z e r f o r t h e d e t e r m i n a t i o n of f a t , p r o t e i n , and l a c t o s e percentage.  F o r t o t a l s o l i d s d e t e r m i n a t i o n 5mls. o f  m i l k were put i n t o an a l r e a d y weighed c r u c i b l e , weighed and t h e n was  crucible  p l a c e d i n a b o i l i n g water b a t h f o r 4 hours and t h e n put i n the oven f o r  3 t o 4 hours u n t i l  constant weight was  obtained.  a g a i n and t h e amount o f t o t a l s o l i d s determined.  C r u c i b l e s were weighed For the determination of  ash c r u c i b l e s c o n t a i n i n g t o t a l s o l i d s were weighed and put i n f u r n a c e f o r 2 hours a t 500°C.  Afterwards t h e y were t a k e n out o f t h e oven at 100°C, c o o l e d  i n a d e s i c c a t o r and weighed a g a i n . o f ash and t h e n t h e percentage determined.  The d i f f e r e n c e i n weight gave t h e amount  i n t h e o r i g i n a l 5 m l . o f m i l k samples  A l l d e t e r m i n a t i o n s were done i n d u p l i c a t e .  was  49  Weaning o f Lambs Bir."bhweight of every lamb was week u n t i l weaning.  recorded  and  they were weighed every  Twenty-seven iambs from both the groups of ewes were  weaned a t 6 to 8 weeks o f age each on a weight b a s i s .  and  d i v i d e d i n t o t h r e e groups of n i n e  Lambs i n Group I r e c e i v e d hay + p e l l e t e d g r a i n  r a t i o n ( 2 0 % . p r o t e i n ) ; Group II, hay + p e l l e t e d g r a i n r a t i o n (16% and  Group III, hay + p e l l e t e d g r a i n r a t i o n (13%, p r o t e i n ) .  the r a t i o n s i s g i v e n i n T a b l e A^2'. amount being r e f u s e d was was  f e d was recorded  determined.  daily.  The  increased gradually. and  protein)  Composition of  P e l l e t s were f e d to a p p e t i t e and The  thus the amount o f hay  amount of hay  given  the  and  consumed d a i l y by each group  amount of p e l l e t s consumed by  T o t a l amount of feed consumed d u r i n g  each group was  10 weeks was  also  the groups r e c e i v e d almost same amount o f t o t a l p e l l e t s and hay  the  10 week p e r i o d a f t e r weaning.  during  Lambs were weighed every week.  Study  Four male lambs from each of the t h r e e groups were used f o r t h i s They were kept i n metabolism cages and p e l l e t s as t h e i r p a r e n t  group.  were kept f o r 5 days d u r i n g  f e d on hay  Water was  and  received  a v a i l a b l e a l l the time.  p r e l i m i n a r y p e r i o d and  They  then the amount of  p e l l e t s consumed each day was  The  study l a s t e d f o r 4 days f o r each a n i m a l d u r i n g which the amount o f  and  u r i n e produced was  recorded  recorded  daily,  u r i n e and  a t the commencement of the  10 ml.  a l s o added to the f a e c e s c o n t a i n e r .  f a e c e s were o b t a i n e d  hay study. faeces  10 ml. of 10%, s u l p h u r i c a c i d was  to the u r i n e c o l l e c t i o n v e s s e l and  ammonia was  study.  the same  and  daily  recorded  also calculated.  All  Digestibility  lambs  a f t e r thoroughly  added  of 2%, b o r i c a c i d to t r a p Representative  samples o f  mixing each and were  brought back to the l a b o r a t o r y where u r i n e samples were put i n the  freezer.  50. F a e c e s samples were put i n the preweighed p e t r i d i s h e s , weighed and dried  f o r 7 hours a t 95°C and reweighed.  f a e c e s was determined.  Dried faeces  So the amount o f dry matter i n  samples were a n a l y z e d  (on dry matter b a s i s ) by K j e l d a h l ' s method. a l s o analyzed analyzed  in duplicate.  L a t e r u r i n e samples were  f o r n i t r o g e n by the same method.  on a dry matter b a s i s .  for nitrogen  Feed samples were a l s o  A l l samples were a n a l y z e d  for nitrogen  51. Experiment No. I I Management T h i r t y l a c t a t i n g D o r s e t ewes, D o r s e t ewe were used f o r t h i s study.  lambs and c r o s s b r e d ewes  They were d i v i d e d e q u a l l y i n t o 3 groups, of  10 ewes each, on a weight b a s i s .  The groups of ewes were a l l o t t e d t o  t h r e e d i f f e r e n t r a t i o n s which p r o v i d e d e q u a l amount of n i t r o g e n to a l l the  t h r e e groups;  Group I was  p r o v i d e d n i t r o g e n from p e l l e t s  containing  soybean meal; Group I I from p e l l e t s c o n t a i n i n g soybean meal + u r e a and Group I I I from p e l l e t s c o n t a i n i n g u r e a a l o n e . for  n i t r o g e n by K j e l d a h l ' s method.  These p e l l e t s were a n a l y z e d  Urea percentage i n the p e l l e t s  was  determined by u s i n g p-dimethylaminobenzaldehyde  (PDAB) and by u s i n g the  b a s i s of the method of Watt and C h r i s p  P e l l e t s were f i n e l y  and a known amount of sample was  (1952).  e x t r a c t e d w i t h water and f i l t e r e d  V o l u m e t r i c f l a s k and made up t o the mark and mixed. d i l u t e d so t h a t the c o n c e n t r a t i o n was t i o n was  20 to 200 mg.  added t o 4 ml. of PDAB s o l u t i o n , mixed  iip. a g a i n s t a b l a n k made i n the same way the  sample.  This solution  ground into a was  %^0.2'ml. of t h i s  solu-  t h o r o u g h l y and read a t 435  by s u b s t i t u t i n g 0.2 ml. water f o r  Sample v a l u e s o b t a i n e d t h i s way were read a g a i n s t a s t a n d a r d  curve made u s i n g f r e s h l y p r e p a r e d known urea s o l u t i o n s . Milk Yield Three D o r s e t ewes from each group were taken f o r m i l k y i e l d d e t e r m i nation.  The method used f o r the d e t e r m i n a t i o n of m i l k y i e l d , c a r r i e d out  once a week f o r 8 weeks, was  the same as i n the f i r s t  experiment except  t h a t an udder cover l i k e the one used by Owen (1957) was udder cover was  a p p l i e d a f t e r f i r s t hand m i l k i n g i n the morning  lambs remained, a l o n g w i t h t h e i r dams i n . t h e same pen. was  removed a f t e r 4 hours a t the time of second m i l k i n g .  24 hours was  employed.  determined.  The  and the  The udder cover Total yield for  52.  Milk Analysis M i l k samples were a n a l y z e d f o r f a t , p r o t e i n , ash by  the same method as i n the f i r s t  lactose, t o t a l solids  experiment.  Samples of m i l k were  a l s o f r e e z e d r i e d f o r l a t e r milk urea n i t r o g e n determination. d r i e d m i l k was percentage  r e c o n s t i t u t e d by  of t o t a l  s i m i l a r except  The f r e e z e  the a d d i t i o n of water on t h e b a s i s of  s o l i d s i n each sample and a n a l y z e d by the method o f  Brown (1959) which i s d e s c r i b e d i n a l a t e r was  and  t h a t m i l k was  u r e a n i t r o g e n l e v e l was  section.  The method employed  Used i n s t e a d of b l o o d plasma and  milk  determined.  Blood A n a l y s i s Blood  samples were taken from  the 30 ewes once a week f o r 8 weeks f o r  the d e t e r m i n a t i o n o f plasma u r e a n i t r o g e n . method of Bfe'own (1959).  Whole b l o o d was  A n a l y s i s was  used  f o r tikis d e t e r m i n a t i o n  the v a l u e s o b t a i n e d were c o r r e c t e d on b l o o d plasma.basis percentage  o f b l o o d plasma i n the whole b l o o d .  because i t was hemolyzed and Blood  not be  after  then f r o z e n .  The  the  and  finding  The whole b l o o d was  c o l l e c t e d i n h e p a r i n i z e d tubes and serum or plasma.could  c a r r i e d out by  the  used blood  taken out o f i t .  samples were a l s o taken every, week from 5 lambs i n each group  f o r a p e r i o d o f 4 weeks.  B l o o d plasma was  used  f o r urea n i t r o g e n determin-  a t i o n by the method mentioned above (Brown, 1959).  The procedure was  as  follows. One  ml. of water ( b l a n k f o r s t a n d a r d s ) , one ml. of u r e a - f r e e plasma  ( o b t a i n e d by adding 3 or 4 drops of urease p r e p a r a t i o n to f i v e ml. of p o o l e d plasma and used as b l a n k f o r unknowns), one ml. a l i q u o t s of the  standards  and one ml. a l i q u o t s of the unknown plasmas were p i p e t t e d i n t o a p p r o p r i a t e l y labelled One  t e s t tubes.  Seven ml. of water was  ml. o f z i n c s u l p h a t e s o l u t i o n was  added to each tube and mixed.  added to each tube and mixed  thoroughly'  53.  One ml. of sodium h y d r o x i d e s o l u t i o n was mixed t h o r o u g h l y . priately  then added t o each tube and  /The contents of the tubes were t r a n s f e r r e d to  coliafoeOfhQsl-  tubes and c e n t r i f u g e d .  again  appro-  Then two ml. a l i q u o t s of the  c l e a r p o r t i o n of the c e n t r i f u g a t e were t r a n s f e r r e d t o a p p r o p r i a t e l y l a b e l l e d cuvettes.  Two  mis. of the p-dimethylaminobenzaldehyde  added to each and mixed t h o r o u g h l y . 10 minutes. at for  400 mu..,  Absorbance was  c o l o r reagent  was  Cuvettes were allowed to stand f o r  measured i n a " S p e c t r o n i c 20"  s e t t i n g the instrument a t zero absorbance  spectrophotometer  w i t h the water b l a n k  the standards and w i t h the u r e a f r e e plasma b l a n k f o r the unknowns.  s t a n d a r d curve was  prepared by p l o t t i n g the absorbances  t r a t i o n s of the s t a n d a r d s .  The  a g a i n s t the  c o n c e n t r a t i o n s of the unknowns was  A  concendetermined  from the s t a n d a r d c u r v e . Growth of Lambs T h i r t y lambs were weaned a t 8 to 10 weeks of age and were d i v i d e d e q u a l l y on the b a s i s of weight  i n t o t h r e e groups and were a l l o t t e d  to t h r e e  d i f f e r e n t r a t i o n s p r o v i d i n g e q u a l amount of n i t r o g e n from soybean, soybean + u r e a and u r e a p e l l e t s . Digestion  Trial  A d i g e s t i o n t r i a l was for  Lambs were weighed weekly f o r 16 weeks.  c a r r i e d out w i t h 2 male lambs from each  5 days a f t e r a p r e l i m i n a r y p e r i o d o f 4 days.  the time.  experiment.  available a l l  Lambs were g i v e n p e l l e t s up t o a p p e t i t e and the amount of p e l l e t s  g i v e n and r e f u s e d was determined.  Water was  group  Faeces  r e c o r d e d and the amount of p e l l e t s consumed  was  and u r i n e were c o l l e c t e d and a n a l y z e d as i n the  first  54 VII.  RESULTS AND DISCUSSION  Experiment I Two groups of ewes were fed two rations providing different levels of energy. Maintenance requirement of Digestible Energy + 50$ and maintenance + 100$ was fed to Group I and Group II, respectively, during late pregnancy. Both the groups were fed 90g. (0.21b.) D.C.P./head/day during late pregnancy and 225g. (0.51b.) D.C.P./head/day during early lactation.  During early  lactation, maintenance requirement of energy + 150$ was fed to Group I and maintenance + 100$ was fed to Group II.  Out of thirty ewes a l l but two  (in the second group) were pregnant and lambed.  Both groups gained weight  during late pregnancy and lost weight during early lactation.  The weight  changes of the ewes are shown i n Fig. I. Average weights of ewes during late pregnancy and early lactation are given i n Table I. Weight gain by the ewes i n Group II during late pregnancy was significantly greater (P<0.01) than that by ewes i n Group I. Weight loss during early lactation was significantly lower (P<Q.05) i n ewes of Group I as compared to ewes i n Group I I . Ewes average daily milk yield i s given i n Table II.  There were no significant  differences i n milk production by the two groups of ewes. The protein supply of the ewes during pregnancy was i n line with the National Research Council (1968) recommendation of 0.21b. Digestible Crude Protein during the last six weeks of gestation for a ewe of L40 lb. live weight or over. However, Phillipson (1959) has suggested 0.25 lb. D.C.P. for ewes of this weight range i n the later stages of pregnancy. Robinson and Forbes (1968) supplied to their ewes a standard digestible crude protein intake of 8.8g/kg. W " ^ 0 7  (W=live weight i n Kg.) or O.42 l b . D.C.P./150 l b . ewe daily during early lactation.  This level of protein was fed i n conjunction with a Metabolizable  Energy intake of 125$ or 150$ of the maintenance requirement of non-pregnant ewes.  They  liveweight  indicated  gain  on  the  that two  the  difference  energy  levels  between the was  about  rates of  Fig I Experiment  80-  Group I Group II  I  Ewe Weights 75»  7<W  65-  60  55  50  45 7 weeks before Parturition  Pre-partum and Pos1>partum weight  U 5 Lactation Weeks  55.  0.06 In  kg./day i n f a v o u r of the h i g h e r l e v e l .  l i n e w i t h Robinson and Forbes  The d i f f e r e n c e was  (1968) experiment  significant.  the p r o t e i n s u p p l i e d  d u r i n g l a c t a t i o n i n t h i s t r i a l should have been adequate. Pre-weaning weekly weights of  of s i n g l e s and twins from both the groups  ewes are shown g r a p h i c a l l y i n F i g . I I .  During the e i g h t weeks of the  l a c t a t i o n s i n g l e lambs i n Group I weighed s i g n i f i c a n t l y h e a v i e r (P^0.05) than those i n Group I I .  S i n g l e and t w i n lamb growth d u r i n g the pre-weaning  p e r i o d i s shown i n T a b l e s I I I and  IV.  Twins i n Group I were a l s o s i g n i f i c a n t l y h e a v i e r (P<0.05) than i n Group I I .  those  S i n g l e lambs from ewes i n Group I I were s i g n i f i c a n t l y h e a v i e r  (P<0.05) than twins from the ewes i n Group I . As a l r e a d y i n d i c a t e d t h e r e were no s i g n i f i c a n t d i f f e r e n c e s i n m i l k y i e l d by the two  groups of the ewes.  d i f f e r e n c e s i n f a t , p r o t e i n and  There were a l s o no  l a c t o s e percentage  significant  of m i l k from the  two  groups. Average d a i l y m i l k p r o d u c t i o n of the ewes and f a t , p r o t e i n and percentage  of the m i l k are shown g r a p h i c a l l y , i n F i g s . I l l and  3Av.erage-'fa!b>, p'toteim <&nd t J f t C O t a S B L i c i * percentages and V I I .  IV a  lactose  e£ad^Witi%  i s g i v e n i n T a b l e s V,  M i l k p r o d u c t i o n i n both groups d e c l i n e d s h a r p l y at the end  the second week a f t e r which the decrease was curves f o r the percentages  gradual.  of p r o t e i n and l a c t o s e was  groups d u r i n g the 8 week p e r i o d . c o n s t a n t i n both the groups.  VI  of  The p a t t e r n of the s i m i l a r i n both  L a c t o s e content of the m i l k was  the  fairly  The p r o t e i n content of the m i l k i n both  the  groups i n c r e a s e d a f t e r the 3rd week when the m i l k y i e l d had d e c l i n e d but i t was  almost  the same from 4 t h week t o the end of the 8 week p e r i o d .  c o n t e n t of the m i l k decreased t h e r e was  a f t e r the f i r s t  g r e a t e r f l u c t u a t i o n d u r i n g the f i r s t  d u r i n g the l a t e r p e r i o d .  t h r e e weeks of l a c t a t i o n  Fat and  t h r e e or f o u r weeks than  The m i l k c o m p o s i t i o n as shown g r a p h i c a l l y  indicated  JJ-e. I l l ..." . Experiment I  ' •  (k£.)  ; Avorafio M i l k y l o l d ,  - §000  (ird,./24  hr)  —_ G r o u p Group  :  'Apoo  •3000 Milk Yield (mis.)  ;2000  3.900  3  :K Ueeks  I Ij  A  Experiment  0  4-000 ml. \^  3000 ml.  I  1st group M i l k Y i e l d and Composition  = protein =  \  o  \  0  lactose $  . = fat % = milk y i e l d  2000 ml.  1000 ml.  13 "12 • •  <  11  \  \  \  \  10  Percentage  9 8  6 5 4 3 4  8  4000 ml.  Fig.Iyt Experiment I Group II  h 3000 ml. \  = protein %  Milk Yield and Composition 4  \  Milk 2000 ml.  Yield  = lactose % = fat %  0  \  = milk yield  (mis) 1000 ml.  U 13  \ \  12  \  11  /'  \  10 9 Percentage  8 7 6 j. 5 4 3  3 Weeks  4  8  t h a t the c o n t e n t o f the above mentioned s o l i d s i n m i l k i n c r e a s e d w i t h a c o r r e s p o n d i n g decrease  i n milk y i e l d .  Gardner and Hogue (1964) p o i n t e d out i n t h e i r experiment  w i t h ewes  t h a t f a t and p r o t e i n v a l u e s were h i g h e r a t the b e g i n n i n g o f l a c t a t i o n , d e c l i n e d to a minimum a f t e r  2 to 4 weeks, remained c o n s t a n t f o r next 3  to 4 weeks and then r o s e with.each a t r i a l p e r i o d o f 12 weeks.  s u c c e s s i v e week o f l a c t a t i o n ,  during  L a c t o s e v a l u e s remained r e l a t i v e l y c o n s t a n t .  TABLE I EXPERIMENT I Average weight o f ewes (Kg.)  Weight o f ewes b e f o r e p a r t u r i t i o n  3roup  7 weeks before parturition weight  Weight of ewes d u r i n g e a r l y l a c t a t i o n  (Weeks)  Prepartum weight  Postpartum weight  1st  2nd  3rd  4th  5th  6th  7 th  8 th  I  56.9  66.0  59.4  60.1  60.6  60.2  59.8  59.3  58.8  57.9  56.9  II  60.2  73.1  65.9  64.6  63.0  61.8  61.0  60.4  60.0  58.8  58.1  TABLE  II  EXPERIMENT Ewes  I  Average D a i l y M i l k Y i e l d  (mls/24 h r . )  Weeks o f Group  1st  2nd  3rd  1st  Group  4500  2136  2316  2nd G r o u p  2940  1896  1656  . . 4th  lactation .  5th .  6th  . .  2308  2220  1840  1734  1645  1248  1380  1221  1227  1165  7th .  . 8th  TABLE I I I EXPERIMENT I S i n g l e Lamb Growth  (Pre-weaning)  Average Weekly Weight (Kg.) Weeks a f t e r Group  Birth Weight  1st  I  .3.8  5.9  6.1  II  4.2  birth  3rd  4th  5th  6 th  7 th  8 th  8.0  10.6  13.1  15.5  18.0  19.9  20.1  7.8  10.1  12.4  14.0  15.6  16.6  18.0  - 2nd  1 TABLE IV EXPERIMENT I Twin Lamb Growth  (Pre-weaning)  Average Weekly Weight (Kg.) Weeks a f t e r  birth  Group  Birth Weight  1st  2nd  3rd  4 th  5 th  6th  7 th  8 th  I  3.4  4.6  6.1  7.7  9.2  12.3  13.2  14.7  15.7  II  3.1  4.5  6.4  7.5  9.1  10.1  11.3  12.5  13.2  TABLE V EXPERIMENT I Average F a t Percentage of M i l k  Week o f L a c t a t i o n  1st  ; 2nd  3rd  4 th  1st Group  -  13.33  13.33  10.66  2nd Group  -  13.42  13.43  9.43  •  5 th  ; 9.ii  .11.41  6 th  7th  8th  8.82  9.65  10.05  11.65  10.75  11.54  TABLE VI -EXPERIMENT J . Average P r o t e i n Percentage of M i l k  Week of L a c t a t i o n  1st  1st Group  -  2nd Group  -  3rd  4th  5th  , 6th  . 7 th  8 th  3.46  ! 3.46  .5.92  ,4.69  '• 5.09  ' 4.97  5.44  3.53  3.53  6.52  4.55  • 5.34  5.28  : 5.88  : 2nd  TABLE VII EXPERIMENT  I  AVERAGE LACTOSE PERCENTAGE OF MILK  Week of Lactation  1st  2nd  3rd  4th  5th  6th  7th  1st Group  -  5.49  5.48  5.80  5.17  6.03  5.51  5.37  2nd Group  -  5.94  5.98  5.66  5.04  5.33  5.41  5.21  8th  Waite fat  e t a l (1968)  and p r o t e i n c o n t e n t  milk y i e l d .  that  for  the  ewes n u r s i n g  compared for  5 week p e r i o d o f  twins  double  i n the experiment  production of to  the 1st  the  lactation.  the p r o d u c t i o n of during  the  lambs w e i g h e d h e a v i e r  twins r e g a r d l e s s of  ewes p r o d u c e h e a v i e r indicated  that  M i l k y i e l d of after  4.  was 4 5 0 0 m l . to  1165  the above  as  i n Group  than pregnancy  l a t e pregnancy. lambs.  Ray  It  the  shows t h a t  and Smith  (1966)  ewes p r o d u c e d h e a v i e r  than d i d the  lighter during  weight heavier  also lambs  at  ewes. f i r s t 2 or 3 weeks  declined.  P r o t e i n and l a c t o s e w e r e  the  least fluctuating  constituents  m i l k a n d w i t h a d e c r e a s e i n t h e m i l k y i e l d t h e r e was a c o r r e s p o n d i n g i n c r e a s e i n the variable during  the  this  f l u c t u a t i o n was  p e r i o d the  increase with  first  solids.  Fat  f o u r weeks o f less,  c o n t e n t was  l a c t a t i o n but  and l a t e r  a corresponding decrease i n milk  more after  t h e r e was yield.  yield  the  discussion.  l e v e l s imposed d u r i n g  t h e ewes was g r e a t e s t  which i t  of  experiment.  the h e a v i e s t  b i r t h and a t w e a n i n g 3.  It  l a m b s a t b i r t h was a f f e c t e d by  dams d u r i n g  indicated  The m i l k  a t b i r t h and a t weaning  the energy  and l a c t a t i o n i n t h i s the  (1961)  in  weeks  respectively.  Single  their  Clark  three  t h e f i r s t week  the groups.  1.  of  that  f i r s t week was m o r e t h a n d o u b l e  f o l l o w i n g c o n c l u s i o n s c a n be drawn from  of  two o r  i n G r o u p I a n d 2940 m l . a s c o m p a r e d  and 8 t h w e e k ,  The w e i g h t  cows  the e i g h t h week.  The  2.  first  the m i l k p r o d u c t i o n of  t h e e i g h t h week i n b o t h  1645 m l .  with  of m i l k i n c r e a s e d w i t h a corresponding decrease  later  l a c t a t i o n was a b o u t obtained  experiment  The m i l k y i e l d was v e r y , h i g h f o r  as compared to  II  indicated in their  an  of  Weaning o f Lambs Twenty  seven lambs were weaned a t 8 to 1 0 weeks of age and d i v i d e d  i n t o three groups. 19.3  T h e i r average w e i g h t a t weaning was  kg. f o r Group I ,  containing 2 0 ,  17.7,  19.3  and  Group I I and Group I I I , and they were f e d p e l l e t s  1 6 and 1 3 7 o crude p r o t e i n , r e s p e c t i v e l y .  g a i n by weaned lambs i s shown i n T a b l e  V I I I  and F i g .  V .  Average d a i l y  TABLE V I I I EXPERIMENT I Post-weaning Lamb Growth Average D a i l y Gain  No.  of Animals  Average D a i l y Gain (kg.)  1 2 3 4 5 6 7 8 9 Average 1 2 3 4 5 \ 6 7 8 9  Ration  0.25 0.24 0.23 0.21 0.17 0.14 0.23 0.20 0.16 ;  20 7, Crude  protein  16.7, Crude  protein  0.20 0.17 0.12 0.10 0.14 0.18 0.14 0.09 0.16 0.12  Average  0.15  1 2 3 4 5 6 7 8 9  0.19 0.13 0.18 0.12 0.16 0.20 0.16 0.17 0.09  Average  0.16  -  137, Crude p r o t e i n  6*,  Results  showed  d a i l y g a i n of  that  t h e r e were  significant differences  lambs f e d p e l l e t s c o n t a i n i n g  lambs f e d the p e l l e t s c o n t a i n i n g gain. 137>  T h e r e w e r e no  and between  i n feed  167,  i n t a k e by  the  p r o t e i n made b e t t e r proportion groups. The  of  The  137>  207, c r u d e p r o t e i n a c h i e v e d  crude p r o t e i n .  three groups.  of  f e e d e f f i c i e n c y r a t i o was 3 . 9 ,  (1966)  Dickson  (1959)  the dominant  reported  compared.to  these  5.7  lambs i s  and 5 . 0  suggested  factor  that rations  for  that after  i n the  two m o n t h s  than r a t i o n s w i t h  not  that rations  s u p p o r t more e f f i c i e n t  Digestion Dry  age,  gains  containing  matter  digestibility is  i s given i n Table XI.  indicate  that  the  differences  d i g e s t i o n c o e f f i c i e n t of  Jordan  weaning,  protein  level.  16.57, p r o t e i n 13.5  to  the  shown i n T a b l e X a n d n i t r o g e n Results  three  retained  significantly  137,  ration. lambs f e d  t h a t 20% C . P .  the d i g e s t i o n  k i n d s of  147,  did  protein.  Lambs f e d t h e  r e t e n t i o n was n o t  16% a n d  13% r a t i o n .  r a t i o n was b e t t e r  than  t r i a l with  (20,  20% C . P . those  of  protein  fed the  of  C.P.)  ration 167,  and  different  the d i g e s t i o n  the growth  and  lambs  16 a n d 137,  significantly  Results for  digested  d i g e s t i b i l i t y and  pellets  ( P < 0 . 0 5 ) more n i t r o g e n  Nitrogen the  of  i n the dry matter  statistically significant.  indicate  age  protein  a lower  containing  IX.  protein,  and  following  approximately  than r a t i o n s  were not  between  28 d a y s  147,  higher  Trial.  retained  C.P.  first  of  Ranhotra  12 a n d  a  two  16 a n d 137,  lamb's d i e t .  c o n t a i n i n g between  8 weeks o f  the other  20,  when weaned  They a l s o r e p o r t e d  137,  shown i n T a b l e  the  6 to  or  differences  lambs f e d  r e s u l t e d i n more r a p i d g a i n s d u r i n g at  greatest  l a m b s f e d 207,  The r e a s o n t h a t  the  g a i n s may n a v e t b e e h ; d u e c t . o '.the. f a c t . t h a t - t h e r e h w a s  feed e f f i c i e n c y r a t i o  g r a s s becomes  between  average  and  the  There were minor  s i n g l e lambs i n t h i s g r o u p ,  respectively.  in  20% a n d 16% p r o t e i n ,  significant differences or  (P<0.05)  lambs,  but  trial 16%  65. CP. ration did not provide extra growth as compared to 13% C P . ration.  TABLE IX EXPERIMENT I POST-WEANING LAMB GROWTH FEED EFFICIENCY RATIO  T o t a l Weight Gain (kg)  20% Crude Protein  16% Crude Protein  13% Crude Protein  130  89.5  102.2  T o t a l Feed Consumed (kg)  510.4  512.2  511.3  Feed Efficiency Ratio  3.9  5.7  5.0  TABLE X EXPERIMENT I DIGESTION TRIAL OF LAMBS DRY MATTER DIGESTIBILITY  No. o f Animals  Total D.M. Intake  D.M. Digested  7o  Ration  8  1  2 1 7 5  2  2 0 3 7  7 2 . 6  3  2 0 2 3  6 8 . 8  4  1 7 5 4  7 4 . 0  1 9 9 7  7 1 . 9  Average  7 2 . 3  1  1 8 8 8  6 2 . 2  2  1 9 0 5  7 5 . 4  3  9 6 1  7 7 . 6  4  1 2 3 4  6 6 . 4  1 4 9 7  7 0 . 4  Average  1  2 1 1 5  6 5 . 1  2  1 9 6 9  7 6 . 0  3  2 1 6 7  6 8 . 3  4  9 6 0  7 1 . 9  1 8 0 2  7 0 . 3  Average  Crude Protein  207o  1 6 7 o Crude Protein  1 3 7 o Crude Protein  TABLE X I EXPERIMENT I DIGESTION TRIAL OF LAMBS NITROGEN DIGESTED AND RETAINED  No. o f Animals  Total N Intake  Digestion coefficient percent - %  8 3 . 4  8 8 . 7  9 1 . 6  2  8 0 . 6  8 5 . 1  9 0 . 9  3  8 0 . 3  8 6 . 4  8 9 . 1  4  7 2 . 6  8 3 . 3  9 2 . 2  Average  7 9 . 2  8 5 . 8  9 0 . 9  .  1  Ration  %  g  1  N Retained N Digested  6 6 . 4  8 8 . 7  8 8 . 2  2  6 4 . 7  8 5 . 6  8 1 . 4  3  3 0 . 0  7 9 . 3  8 6 . 5  4  4 1 . 5  8 7 . 9  8 9 . 3  Average  5 0 . 6  8 5 . 3  8 6 . 3  1  6 0 . 1  8 2 . 6  8 5 . 7  2  5 7 . 2  8 4 . 7  8 0 . 6  3  6 1 . 2  8 0 . 5  8 5 . 5  4  2 8 . 9  6 7 . 1  8 6 . 5  Average  5 1 . 8  7 8 . 7  8 4 . 5  207=  Crude Protein  167o  Crude Protein  137o  Crude Protein  EXPERIMENT I I D u r i n g e a r l y l a c t a t i o n , n i t r o g e n was  provided  to ewes i n equal amounts .  i n t h r e e d i f f e r e n t forms i n p e l l e t e d r a t i o n s c o n t a i n i n g  supplemental  nitrogen  Ewes average d a i l y  as  milk y i e l d  soybean, +  soybean + urea, and  i s shown i n T a b l e X I I and  urea alone.  F i g . VI.  There were no s i g n i f i c a n t  d i f f e r e n c e s observed i n average d a i l y m i l k p r o d u c t i o n rations.  Ward e t a l (1955) r e p o r t e d  c o r r e c t e d m i l k ) was  not  that milk production  significantly  p r o t e i n sparing  12.9  to  increasing  17.97c  e f f e c t of u r e a can only The  low  17.97,  r e s u l t e d i n no  protein ration.  They  This stated  p r o t e i n r a t i o n to  increase  s i g n i f i c a n t mean change i n m i l k  When they added u r e a to a normal p r o t e i n r a t i o n (177, crude  a d e c l i n e i n milk y i e l d occured.  O t a g a k i et a l (1956) a l s o r e p o r t e d i n milk production  There were no  T h i s was  t h a t there was  between c o n t r o l cows and  which 2 1 7 , o f n i t r o g e n  requirement was  no  statistical  s u p p l i e d by  three groups.  t o t a l s o l i d s are given IX.  The  urea.  In a l l the  l a c t o s e percentage) f o l l o w e d  lactose  three groups of ewes,  Average f a t , p r o t e i n ,  i n T a b l e s X I I I , XIV,  m i l k y i e l d and  difference  a group of cows f e d a r a t i o n i n  s t a r t e d to d e c l i n e a f t e r the 4th week.  F i g s . V I I , V I I I and  however not s i g n i f i c a n t .  s i g n i f i c a n t d i f f e r e n c e s i n f a t , p r o t e i n and  percentage of m i l k from the  l a c t o s e and  determined  r e s u l t e d i n a s i g n i f i c a n t inanase i n milk production.  the crude p r o t e i n to  milk y i e l d  be  a d d i t i o n of p r o t e i n to such  t h a t the a d d i t i o n of s u f f i c i e n t u r e a to such a low  protein)  (1947)  the percentage of crude p r o t e i n i n the r a t i o n from  c o n f i r m e d the p r o t e i n d e f i c i e n c y o f the  production.  i n F.C.M. ( f a t  B a r t l e t t a n d Bl&xter  i n animals f e d a p r o t e i n d e f i c i e n t r a t i o n . a r a t i o n , by  these  d i f f e r e n t when cows were f e d a  c o n c e n t r a t e w i t h soybean meal or u r e a . emphasized t h a t any  of ewes fed  >XV"  s o l i d s ( f a t and  an almost s i m i l a r p a t t e r n  and  XVI,  protein  to the  first  and and  F i g VI' flLlk Y i e l d (Ml.)  Experiment  II  Milk Yield  = soybean - - = soybean & urea = urea  3000  2500  2000  1500  1000  8 Weeks  F i g . VII Experiment I I Soybean Ration  fepOO ml.  = protein % = lactose % = fat % = milk y i e l d  Milk Yield : o'  2000 ml.  11000  ml.  12 11  \  10 Percentage  \  9  \  8  7 6  .5  > •  1  r—  i  i  2  6  Weeks  7  1—  8  P i g . -VI-IIExpjrljient I I \ Urea & /-Soybean''ration  = protein % = lactose $  1-3000 ml.  = fat % - milk y i e l d  / 2000 ml. Milk Yield  h 1000 ml.  13 12 11 10  \  Percentage  8 7 6 5 4  Weeks  "Fig. 1X1: Experiment I I \ Urea ration  = protein % = lactose %  I 3000 ml. ..  = fat %  _____ = milk yield  I  2000 ml.  \  h 1000 ml.  12 11 10 9 8  Percentage  7  \ \  \  70.  experiment,  t h a t i s t h e r e was an i n c r e a s e i n the percentage  w i t h a c o r r e s p o n d i n g decrease i n m i l k y i e l d . is  shown i n T a b l e XVII.  o f these  solids  Ewes average m i l k urea N l e v e l  There were no s i g n i f i c a n t d i f f e r e n c e s i n ewes m i l k  u r e a n i t r o g e n l e v e l among t h e t h r e e groups b u t t h e r e was v a r i a t i o n w i t h i n the groups which was independent  o f the m i l k y i e l d .  The range  i n milk urea  n i t r o g e n l e v e l was from 2.7 t o 7.5, 0.2 to 5.7, and 0«3 to 5.3 mg/100 m l . f o r u r e a , u r e a + soybean and soybean c o n t a i n i n g p e l l e t s ,  respectively.  B r i g g s and Hogg (1964) r e p o r t e d t h a t i n cows g i v e n u r e a the range i n m i l k u r e a l e v e l was from  15 to 44 mg/100 m l .  In cows f e d c o n v e n t i o n a l  r a t i o n s i n c l u d i n g p r o t e i n supplements the range was from 33 to 58 mg/100 m l . but the d i f f e r e n c e s were n o t s i g n i f i c a n t . m i l k o f sheep i s lower  I t seems t h a t l e v e l s o f u r e a i n  than t h a t i n cow's m i l k as i n d i c a t e d by t h i s  experiment.  They a l s o r e p o r t e d t h a t these l e v e l s o f u r e a d i d n o t a f f e c t the q u a l i t y o f cow's m i l k .  S i n c e the l e v e l o f urea i n sheep m i l k i s f a r lower  than  i n the cow's m i l k , as i n d i c a t e d by the r e s u l t s o f t h e experiment,  that  there i s  l e s s p o s s i b i l i t y o f the q u a l i t y o f sheep m i l k being a f f e c t e d by t h e u r e a secretion i n milk.  B r i g g s and Hogg (1964) a l s o r e p o r t e d t h a t m i l k u r e a  e x c r e t i o n was 1.4 to lO.Og/day and 3.7 t o l7.3g/day and p r o t e i n supplemented r a t i o n s , r e s p e c t i v e l y .  f o r urea  supplemented  T h e i r work suggests  that  f e e d i n g u r e a to d a i r y cows has no s i g n i f i c a n t e f f e c t on the l e v e l or output of u r e a i n t h e m i l k . Ewes Blood A n a l y s i s . Ewes average  plasma urea N l e v e l i s g i v e n i n T a b l e X V I I I .  the b l o o d a n a l y s i s showed t h a t these were no s i g n i f i c a n t  Results of  differences  between plasma u r e a n i t r o g e n l e v e l ( d u r i n g f i r s t 8 weeks o f l a c t a t i o n ) o f ewes f e d soybean or soybean + u r e a c o n t a i n i n g p e l l e t s . p e l l e t s had s i g n i f i c a n t l y  lower  Ewes f e d these  (P<0.05) plasma u r e a n i t r o g e n l e v e l  than  71. TABLE  XII  EXPERIMENT  II  EWES AVERAGE D A I L Y M I L K Y I E L D (mis/24 hr)  WEEKS OF j  i  \  i  5th  6 th  7 th  8 th  -  2360  2310  2340  1454  1813  2430  -  2720  2320  2450  2260  2133  2550  -  2880  2400  1965  2310  1786  1st  2nd  Soybean  1880  2120  Soybean  1920  1813  Urea  > \  j  4th  RATION  + Urea  LACTATION  3rd  TABLE X I I I EXPERIMENT I I AVERAGE FAT'PERCENTAGE OF MILK  WEEKS OF LACTATION  RATION  1st  2nd  3rd  4th  5 th  6 th  7 th  8th  Urea  10.48  11.17  8.56  8.37  8.51  7.74  8.45  9.47  Urea + Soybean  12.18  11.01  11.84  8.12  9.86  9.74  10.36  10.17  Soybean  11.14  8.95  9.70  7.42  8.94  9.35  7.94  7.36  TABLE XIV EXPERIMENT I I AVERAGE PROTEIN PERCENTAGE OF MILK  WEEKS OF LACTATION  RRATION  1st  2nd  3rd  4 th  5 th  6 th  7 th  8 th  Urea  4.22  4.56  5.26  5.79  5.25  5.61  5.07  5.94  Urea + Soybean  4.39  4.40  4.58  5.31  4.91  5.11  5.17  5.45  Soybean  4.78  4.51  4.38  4.70  5.79  5.16  4.86  5.47  TABLE XV EXPERIMENT  II  AVERAGE LACTOSE PERCENTAGE OF M I L K  WEEKS OF  LACTATION  RATIONS  1st  2nd  3rd  4 th  5 th  6 th  7 th  8 th  Urea  4.73  4.84  4.94  4.77  4.59  5.17  5.25  4.66  Urea + Soybean  4.59  4.86  5.02  5.21  4.74  4.21  4.85  4.74  Soybean  4.78  5.32  5.32  5.18  4.68  4.89  5.16  5.06  TABLE XVI EXPERIMENT I I AVERAGE TOTAL SOLIDS PERCENTAGE OF MILK  WEEKS OF LACTATION  RATIONS  1st  2nd  3rd  4 th  Urea  20.13  21.30  19.46  19.63  Urea + Soybean  21.92  21.07  22.24  Soybean  21.43  19.58  20.13  5 th  6 th  7 th  8 th  19.10 19.32  19.47  20.82  19.47  20.34 19.89  21.20  21.16  18.03  20.13 20.16  18.71  18.65  TABLE  XVII  EXPERIMENT  II  EWES AVERAGE M I L K UREA...N ( m g . . U r e a N / 1 0 0 m l . )  WEEKS OF  LACTATION  RATIONS  1st  2nd  3rd  4 th  5 th  6th  7 th  8 th  Soybean  2.1  5.3  2.0  2.3  0.3  2.6  2.8  2.0  Soybean + Urea  0.2  4.8  3.8  0.8  1.3  2.2  4.5  6.1  Urea  3.5  7.5  2.3  6.7  2.7  4.3  4.8  5.5  76. those f e d p e l l e t s c o n t a i n i n g u r e a a l o n e .  D r o r i and L o o s l i  (1961) a l s o  r e p o r t e d t h a t u r e a n i t r o g e n i n b l o o d of sheep r o s e a f t e r d i e t s w i t h urea and f e l l a f t e r d i e t s w i t h soybean meal but the d i f f e r e n c e s were n o t significant.  The ewes plasma u r e a n i t r o g e n l e v e l i n t h i s  experiment  v a r i e d from 19.0 t o 30.5, 23.6 t o 48.1 and 31.5 to 48.6 mg/100 ml., f o r soybean,  soybean + u r e a and u r e a c o n t a i n i n g p e l l e t s ,  respectively.  Lamb Growth Average weekly weights o f lambs d u r i n g t h e - p r e - w e a n i n g i p e r i o d ' a T e n g i v e n in  T a b l e XIX and g r a p h i c a l l y i n F i g X.  The growth c u r v e s o f lambs  n u r s i n g ewes f e d on soybean + u r e a and u r e a c o n t a i n i n g p e l l e t s o v e r l a p eath o t h e r d u r i n g the pre-weaning  period, indicating  l i t t l e difference i n  the growth o f lambs s u c k l i n g ewes f e d on these type o f p e l l e t s . c u r v e s o f the lambs n u r s i n g ewes f e d soybean slower growth by such lambs.  Growth  c o n t a i n i n g p e l l e t s showed  S t a t i s t i c a l a n a l y s i s showed t h a t t h e r e were  no s i g n i f i c a n t d i f f e r e n c e s i n t h e pre-weaning  growth o f lambs n u r s i n g  ewes f e d on p e l l e t s c o n t a i n i n g soybean + u r e a , and u r e a a l o n e , and those lambs from ewes f e d on p e l l e t s c o n t a i n i n g soybean made s i g n i f i c a n t l y slower g a i n (P<0.05) than those from the o t h e r two groups. t h i s slower r a t e o f g a i n i s d i f f i c u l t  The reason f o r  to e x p l a i n .  Average weekly weights o f lambs d u r i n g t'hetpostsweaningxperI<5d;.'ar@rtgiven in  T a b l e XX and F i g . X I . D u r i n g the post-weaning  lambs f e d on p e l l e t s c o n t a i n i n g soybean  p e r i o d o f 16 weeks,  gained s i g n i f i c a n t l y greater  (P<0.05) than those on p e l l e t s c o n t a i n i n g u r e a a l o n e , b u t theEe were no s i g n i f i c a n t d i f f e r e n c e s i n the weight g a i n o f lambs f e d on p e l l e t s c o n t a i n i n g soybean  o r soybean + u r e a and soybean + u r e a or u r e a a l o n e .  T h i s i n d i c a t e d t h a t p e l l e t s c o n t a i n i n g soybean proved b e t t e r f o r the growth o f lambs than those c o n t a i n i n g u r e a a l o n e .  Fig.  X  Experiment  II  soybean  Lamb Growth  soybean & urea  (Pre-weaning)  urea  Weeks  .Fig XI ' Experiment II Lamb Growth Rate (Post-weaning)  = soybean ----•  = soybean & urea  •  = urea  4 3  3 8  3 3  Weight . (Kg.)  28  2 3  18  ,  0 ' 1  2  3 " 4  5  6  7  8  9  Weeks  1  0  1  1  1  2  1  3 H  15  1  6 17  TABLE X V I I I EXPERIMENT  II  EWES AVERAGE PIASMA UREA N (mg. Urea N/100 ml)  WEEKS OF LACTATION  6 th  7 th  8 th  1st  2nd  3rd  4th  5th  Soybean  26.0  28.9  28.2  27.1  30.5  28.7  19.0  27.1  Soybean + Urea  23.7  29.2  27.7  25.3  45.0  27.8  27.0  33.6  Urea  30.7  33.4  35.8  33.9  47.2  32.8  33.9  39.1  RATIONS .  TABLE XIX EXPERIMENT I I LAMB GROWTH (PRE-WEANING) AVERAGE WEEKLY WEIGHTS (kg)  WEEKS AFTER BIRTH  RATIONS  BIRTH WEIGHT  1st  2nd  3rd  4th  Soybean  4.7  5.7  7.2  8.6  10.5  13.5  14.7  17.3  19.8  21.5  Soybean + Urea  4.0  5.9  7.6  9.0  12.3  15.3  16.8  19.3  19.9  23.8  Urea  4.0  6.2  7.5  9.7  13.0  15.0  17.4  19.4  22.2  24.8  5 th  6 th  7 th  8 th  9 th  79, r a t i o s were 4 . 0 ,  Feed c o n v e r s i o n u r e a and  5*1  and  5*9  f o r soybean, soybean  urea containing p e l l e t s , r e s p e c t i v e l y .  Lambs plasma Urea N l e v e l i s i n d i c a t e d i n T a b l e There were no  XXI.  s i g n i f i c a n t d i f f e r e n c e s between plasma urea  l e v e l o f lambs f e d on soybean o r soybean £ u r e a c o n t a i n i n g Lambs f e d t h e s e two  t y p e s o f p e l l e t s had  nitrogen  pellets.  s i g n i f i c a n t l y higher  (P<0.05)  plasma urea n i t r o g e n l e v e l t h a n t h o s e f e d p e l l e t s c o n t a i n i n g u r e a Plasma u r e a n i t r o g e n l e v e l f o r lambs v a r i e d from 25.2 28.1  and  ^  20.0  t o 26.9  mg./lOO ml.,  containing p e l l e t s , respectively. urea l e v e l was  different  t o v a r i a t i o n i n the  i n the  for.soybean, The  levels.  from 2.7  soybean ^ - u r e a and  to urea blood  case o f lambs compared t o ewes could be  Preston  v a r i a t i o n i n t h e p r o t e i n i n t a k e o f the nitrogen ranging  19.6  reason t h a t t h e p i c t u r e o f the  p r o t e i n i n t a k e o f the  g r e a t e r v a r i a t i o n i n BUN  t o 26.3,  alone.  t o 32.9  growing lambs, which can  due  cause  et a l (1965) r e p o r t e d t h a t  the  growing lamb r e s u l t e d i n b l o o d  urea  mg./lOO ml.  D i g e s t i o n T r i a l o f Lambs. Dry m a t t e r d i g e s t i b i l i t y and i n Tables  XXII and  XXIII.  n i t r o g e n r e t a i n e d and  R e s u l t s o f the d i g e s t i o n t r i a l w i t h lambs showed  t h a t a l t h o u g h t h e p r o t e i n d i g e s t i o n c o e f f i c i e n t and was  d i g e s t e d i s shown  dry matter d i g e s t i b i l i t y  h i g h e r f o r p e l l e t s c o n t a i n i n g u r e a , the d i f f e r e n c e s between p e l l e t s  c o n t a i n i n g soybean, soybean-4-urea and significant.  statistically  P e l l e t s p r o v i d i n g n i t r o g e n from soybean r e s u l t e d i n g r e a t e s t  nitrogen retention. urea was  u r e a a l o n e , were not  Nitrogen  r e t a i n e d from p e l l e t s c o n t a i n i n g soybean  g r e a t e r t h a n t h a t from p e l l e t s c o n t a i n i n g u r e a a l o n e .  d i f f e r e n c e s were s i g n i f i c a n t  (P<0.05).  from p e l l e t s c o n t a i n i n g u r e a and was the u r i n e .  D r o r i and  Loosli  due  Least  The  n i t r o g e n r e t e n t i o n was  obtained  to greater excretion of nitrogen i n  ( l 9 6 l ) a l s o r e p o r t e d t h a t d i e t s w i t h soybean  meal gave b e t t e r n i t r o g e n r e t e n t i o n and had a h i g h e r b i o l o g i c a l v a l u e diets with urea. urea i n the u r i n e .  than  They i n d i c a t e d t h a t t h i s was r e l a t e d to the e x c r e t i o n o f  TABLE XX EXPERIMENT I I LAMB GROWTH RATE  (POST-WEANING)  AVERAGE WEEKLY WEIGHT (kg)  WEEKS AFTER WEANING  6 th  7 th  10th  11th  12 th  13 t h  14th  15 th  16 th  29.0  31.4  32.3  33.6  35.0  35.8  37.0  36.0  31.5  32.9  34.1  35.5  36.5  37.7  37.3  38.6  38.7  32.7  34.0  34.9  36.5  38.0  36.4  36.8  37.1  37.3  8 th  RATIONS  1st  2nd  3rd  4 th  5 th  Soybean  18.6  21.9  22.0  23.1  24.4  24.7  25.0  27.3  Soybean + Urea  23.9  25.3  26.1  27.0  28.1  29.1  30.3  Urea  23.7  24.8  26.1  27.0  27.1  29.3  31.0  9 th  TABLE XXI EXPERIMENT I I LAMBS AVERAGE PLASMA UREA N (mg. Urea N/100 ml.)  WEEKS DURING POST-WEANING PERIOD  RATION  1  2  3  4  Soybean  26.3  32.2  32.5  27.2  Soybean + Urea  19.7  27.7  28.1  22.7  Urea  21.1  26.0  26.9  20.0  TABLE XXII EXPERIMENT  II  DIGESTION TRIAL OF LAMBS  DRY MATTER  NO. OF ANIMALS  TOTAL D.M. INTAKE  DIGESTIBILITY  % D.M. DIGESTED  RATION  g*  1  4529  58.6  2  4329  60.9  AVERAGE  4429  59.7  1  4529  47.2  2  4192  70.1  AVERAGE  4360  58.6  1  3264  60.0  2  4128  62.3  AVERAGE  3698  61.4  Soybean.  Soybean + Urea  Urea  TABLE X X I I I EXPERIMENT I I DIGESTION TRIAL OF LAMBS NITROGEN DIGESTED AND RETAINED  NO. OF ANIMALS  TOTAL N INTAKE g  DIGESTION COEFFICIENT PERCENT X  N RETAINED 7 N DIGESTED  1  45.2  55.7  84.1  2  43.2  62.2  80.7  44.2 •  58.9  82.4  1  45.2  64.8  73.0  2  41.8  66.9  73.2  AVERAGE  43.5  65.8  73.1  AVERAGE  1  32.5  83.3  62.3  2  41.2  75.4  64.9  AVERAGE  36.8  79.3  63.6  RATION  Soybean  Soybean + Urea  Urea  VIII  LITERATURE CITED  1. Abou Akkada, A. R. and T. H. 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A g r i c . S c i . __j:133-136. 88.  Warren, K. S. 1962. Ammonia t o x i c i t y and  89.  Watt, G. W. and J . D. Chrisp. 1952. A spectrophotometric method, f o r the . determination of hydrazine. Anal. Chem. 24:2006. Wegner, M. I . , A. N. Booth, G. Bohstedt and E. B. Hart. 1940. J . Dairy S c i . The i n v i t r o conversion of inorganic nitrogen t o p r o t e i n by T'tiii Pro organisms from the cow's rumen. J . Dairy S c i . 23_:1123-1129.  90.  91.  pH.  Nature.  195:47-49.  Wright, P. L., A. L. Pope and P. H. P h i l l i p s . 1964. P e l l e t e d roughages f o r gestating and l a c t a t i n g ewes. Nutr. A b s t r . Rev. 34:254.  92.  IX  APPENDICES  93.  TABLE EXPERIMENT I COMPOSITION OF RATIONS FOR EWES DURING LACTATION  Feed  Grass hay  Alfalfa hay  Beet pulp  Dairy pellets  No. of Samples  Crude Proteins  % Ash  1  11.4-9  7.2  2  11.64  7.3  Average  11.56  7.2  . 14.48  6.7  1 2  -  6.S  Average  14.48  6.7  1  10.72  7.8  2  10.51  3  9.95  4  9.86  Average  10.26  7.3  1  14.08  6.97  2  -  6.90  Average  14.08  6.93  TABLE 3X2 EXPERIMENT RATION  I  COMPOSITION  (FOR WEANED LAMBS)  Ration (Protein level)  2 0 %  No. of Samples  1  18.9  2  19.7  3 1  16%  Crude Protein (after analysis)  9  .  15.4  1 2 1  6  .  3  1 3 %  8  0 16.1  1  13.0  2 1  2  .  8  3 1  3  .  2  95  TABLE :: A-3. EXPERIMENT I WEIGHT OF EWES (Kg) WEIGHT OF EWES BEFORE PARTURITION 7 Weeks Before Pre- PostNo. of P a r t u r i t i o n Partum Partum Ewes Weight Weight Weight  GROUP I  WEIGHT OF EWES DURING EARLY LACTATION (Weeks of lactation) 1st 2nd  3rd 4th  5th 6th 7th 8th  .1  65  69  65  70  72  71  71  74  76  74  74  2  61  75  67  66  70  65  69  68  68  64  63  3  65  73  65  65  64  62  64  62  62  62  59  4  49  53  47  49  45  49  48  48  47  48  47  5  60  75  68  67  65  64  62  64  65  66  66  R  •r  u U "D r T  6  57  67  59  63  63  64  61  53  57  55  50  7  79  95  79  89  84  81  81  80  80  70  71  8  65  73  68  65  66  67  67  65  64  56  59  9  60  78  71  70  66  64  62  64  65  68  67  10  71  81  79  79  80  79  79  75  76  71  71  11  50  55  50  49  53  58  54  53  55  52  52  12  42  48  a  44  47  45  45  43  42  44  53  13  43  49  41  44  44  40  39  42  38  44  41  14  42  51  44  45  44  46  44  45  43  44  39  15  39  45  42  40  40  43  45  45  41  43  43  1  TABLE  A-3  EXPERIMENT  I  WEIGHT OF EWES (Kg)  WEIGHT OF EWES BEFORE PARTURITION 7 Weeks Before No. of P a r t u r i t i o n Ewes Weight  P r e - PostPartum Partum Weight Weight  GROUP I I  WEIGHT OF EWES DURING EARLY LACTATION (Weeks o f l a c t a t i o n )  Lst  2nd  3rd  4th  5th  6th  7th  8th  65  76  68  65  62  62  59  59  60  61  57  2  56  72  66  65  64  62  60  62  66  61  60  3  69  80  74  70  72  70  70  72  75  74  73  4  46  55  50  48  48  a  . 45  50  45  43  44  5  42  60  48  52  50  49  47  44  43  42  43  6  69  83  76  75  74  72  71  67  65  64  62  7  65  80  75  72  72  61  74  72  71  70  60  8  85  98  89  87  84  80  79  78  77  76  77  9  65  78  73  71  70  69  69  66  67  67  69  10  69  82  76  74  71  68  70  68  67  68  71  11  43  49  92  a  40  40  40  39  39  38  39  12  42  51  46  45  43  44  42  42  40  38  38  13  61  80  62  68  64  64  62  60  60  54  55  1  97. '  :  •  TABLE A-4 EXPERIMENT  I  SINGLE LAMB GROWTH (PRE-WEANING) WEEKLY WEIGHTS (Kg)  l. OF ' BIRTH ANIMALS WEIGHT  1st  2nd  3rd  4th  5th  6th  7th  1  2.7  4.8  6.7  8.4  10.2  12.7  15.4  16.0  2  5.0  7.7  10.5  14.0  16.4  18.1  19.5  21.3^  3  4.0  5.6  7.0  9.3  12.7  16.3  19.0  20.0  4  5.1  7.7  10.9  13.5  15.9  18.6  21.3  22.7  5  4*2  6.5  9.0  11.7  14.5  16.8  20.4  23.1  6  3.7  6.0  •.=8.5  12.2  15.0  17.7  20.0  22.2  7  3.2  4.3  5.9  8.0  10.2  12.2  14.5  16.8  8  3.2  5.5  7.0  8.5  11.3  13.1  15.9  16.3  9  3.0  5.1  9.3  12.4  14.0  16.0  20.0  1  4.0  6.3  7.9  10.0  13.6  15.9  17.2  18.6  2  4.7  6.0  7.4  11.3  13.2  14-.5  15.9  16.8  3  3.6  5.7  7.4  9.5  12.7  13.2  15.0  15.9  4  4.1  6.9  8.7  11.5  13.6  15.0  15.4  16.8  5  4-2  4-7  6.5  9.0  11.8  13.6  15.4  15*4  6  5.7  8.5  14.5  16.8  19.0  21.3  21.8  7  4.0  5.3  10.0  11.3  13.1  15.4  16.8  8  3.3  5.2  6.6  7.5  9.5  10.9  11.3  13.6  9  4.5  6.7  7.8  7.8  10.0  10.9  13.6  14.5  7.2  11.1  7.0  GROUP I  GROUP II  98.  TABLE A-5 EXPERIMENT  I  TWIN LAMB GROWTH (PRE-WEANING) WEEKLY WEIGHTS (Kg. )  NO. OF ANIMALS  BIRTH WEIGHT  WEEKS  AFTER  1st  2nd  BIRTH 3rd  4th  5th  6th  7th  8th  8,5  11.8  11.8  13.6  15.0  14.0  14-5  16.3  17.7  1  2.7  4.3  5.5  7.4  2  2.9  4.8  6.9  8.8  11.0  3  4.0  4.7  5.9  7.5  8.5  11.3  12.7  14«0  14.0  7.3  8.9  12.2  13.8  15.0  16.3  9.0  10.6  11.8  11.8  4  3.8  4.9  6.0  1  3.2  4.4  6.4  7.2  2  2.5  3.5  5.1  6.2  7.2  8.0  9.3  10.9  11.8  3  3.2  4.8  6.0  8.5  10.9  12.7  13.6  14.5  15.9  4  3.7  5.5  7.2  8.0  10.0  10.9  11.8  12.8  13.6  8.4  G R  0 u p I  G R  0 u p II  99 TABLE A-< EXPERIMENT  I  DRY MATTER DIGESTIBILITY OF WEANED LAMBS  RATION (PROTEIN LEVEL)  20%  16$  NO. OF ANIMALS  TOTAL D.M. LOST FOR 4 DAYS  TOTAL D.M. DIGESTED FOR 4 DAYS  g  g  g  %. D. M. DIGESTED  1  2175  601  1574  72.3  2  2037  558  1479  72.6  3  2023  630  1393  68.8  4  1754  455  1299  74.0  Average  1997  561  1436  71.9  1  1888  713  1175  62.2  2  1905  468  1437  75.4  3  961  215  746  77.6  4  1234  414  820  66.4  1497  452  1047  70.4  1  2115  737  1378  65.1  2  1969  471  1498  76.0  3  2167  685  1482  68.3  4  960  269  691  71.9  1802  540  1262  70.3  Average  \ 13%  TOTAL D.M. INTAKE FOR 4 DAYS  Average  TABLE A-7 • EXPERIMENT I N. DIGESTED AND RETAINED BY WEANED LAMBS  RATION (PROTEIN LEVEL)  NO. OF ANIMALS  TOTAL N. INTAKE FOR •;• 4 DAYS  1 2 20$  3  g 83.4 80.6 80.3  4 Average  TOTAL N. DIGESTED FOR 4 DAYS  DIGESTION COEFFICIENT PERCENT  TOTAL N. TOTAL N. TOTAL N. LOST IN LOST FOR RETAINED URINE FOR 4 DAYS FOR 4 DAYS (faeces & L DAYS urine) g g  N. RETAINED N. DIGESTED  g  g  9.2  74.2  88.7  6.2  15.4  68.0  91.6  12.0  68.6  85.1  6.2  18.2  62.4  90.9  10.9  69.4  86.4  7.5  18.4  61.9  89.1  12.1  60.5  83.3  4.7  16.8  55.8  92.2  11.0  68.1  85.8  6.1  17.2  62.0  90.9  7.5  58.9  88.7  6.9  14.4  52.0  88.2  55.4  85.6  10.3  19.6  45.1  8I.4  79.2  1  66.4  2  64.7  3  30.5  6.2  23.8  79.3  3.2  9.4  20.6  86.5  4  41.5  5.0  36.5  87.9  3.9  8.9  32.6  89.3  50.6  7.0  43.6  85.3  6.0  13.0  37.5  86.3  1  60.1  10.4  49.7  82.6  7.1  17.5  42.6  85.7  2  57.2  8.7  48.5  84.7  9.4  18.1  39.1  80.6  3  61.2  11.9  49.3  80.5  7.1  19.0  42.2  85.5  4  28.9  9.5  19.4  67.1  2.6  12.1  16.8  86.5  51.8  10.1  41.7  78.7  6.5  16.6  35.1  84.5  16$  Average 13$  72.6  TOTAL N. LOST IN FAECES FOR 4 DAYS  Average  9.3  101. TABLE A-8 EXPERIMENT II PERCENTAGE OF UREA IN RATIONS  RATION Soybean  NO. OF SAMPLES  % UREA IN RATION  1  0.07  2  0.07  3  0.06  Average  0.06  Soybean  1  0.90  &'  2  1.00  3  0.80  Urea  Average  Urea  0.90  1  1.90  2  2.00  3  2.00  Average  1.96  102. TABLE A-9 EXPERIMENT II LAMB GROWTH (Pre-weaning) WEIGHTS IN KGS. SOYBEAN  NO. OF _}MBS  BIRTH WEIGHT  1  2  Weeks after birth 6 3 5 4  7  8  9  1  3.8  6.5  8.4  10.9  34.0 15.9 16.8  19.0  21.3  24.5  2  4.3  6.3  8.4  10.4  15.4  16.3  18.1  22.7  26.8  27.2  3  3.8  5.6  7.9  9.7 11.3  15.9  17.2  19.0  21.3  23.1  4  4.1  5.9  7.5 10.9  13.1  15.0  18.1  20.9  20.9  20.9  5  5.0  7.7  7.9  10.0  13.1  14.1 18.1  20.9  23.6  6  4.3  5.4  6.1  8.4  11.3  11.3  16.8  16.8  18.3  7  2.5  4.3  5.4 6.5  7.5  10.4  11.8  13.1  15.9  17.5  8  3.6  5.2  7.5 7.2  14.0 14.5 17.2  20.0  9  3.2  5.4  5.4  9.0 10.6  10  4.6  6.3  7.2  7.7  11  3.7  4.3  5.2 7.2  Average  4.7  5.7  7.2  8.8 6.8  8.8 14.0 15.0  15.4  17.2  21.8  23.6  8.8 11.8  12.7  15.0  17.5  18.1  12.7  14.0 16.8  18.1  8.6  11.8  8.6 10.5 13.5 14.7 17.3 19.8  21.5  103  TABLE A-9 EXPERIMENT II LAMB GROWTH (Pre-weaning) WEIGHTS IN KGS.  SOYBEAN AND UREA  NO. OF LAMBS  • BIRTH WEIGHT  after t  1  2  3  4  6  5  7  8  9  1  3.1  4.5  5.9  7.2  9.0  13.1  13.1  15.9  17.2  20.0  2  3.1  4.5  5.4  6.8  8.6  12.2  13.1  15.0  16.8  18.6  3  4.8  6.8  8.8  10.9  15.0  17.2  19.0  22.2  23.6  25.0  4  3.8  4.5  6.8  7.9  9.0  14.0  15.4  17.2  18.6  22.2  5  3.6  5.0  6.3  7.2  8.8  13.1  14.5  16.3  17.5  19.0  6  4.7  7.9  9.3  7  4.8  6. 5  8.6  8  3.6  5.0  9  4.1  10 11  Average  12.2  \  15.9  18.1  19.0  20.9  22.2  24.5  11.1  15.0  16.8  19.0  20.9  23.6  27.2  6.5  7.2  10.0  12.7  15.0  17.2  19.0  21.8  6.3  9.3  11.3  14.3  17.7  20.0  25.0  26.8  30.0  4.4  6.5  8.1  9.7  13.1  15.9  17.2  19.0  22.2  25.4  4.8  7.0  8.8  11.3  16.8  17.7  19.0  22.2  24.5  28.6  4.0  5.9  7.6  9.0  12.3  15.3  16.8  19.3  19.9  23.8  TABLE A-9 EXPERIMENT II LAMB GROWTH (Pre-weaning) WEIGHTS IN KGS. UREA NO. OF JAMBS  BIRTH WEIGHT  1  2  3  4  Weeks after birth6 7 5  8  9  1  3.0  4.5  5.6  6.8  9.5  11.3  14.0  15.9  18.1  20.0  2  3.5  5.4  6.3  7.9  11.3  12.7  15.0  16.3  18.6  20.9  3  4.0  6.1  7.2  8.8  12.2  13.6  16.3  17.5  20.4  22.7  4  3.4  5.6  6.3  8.1  13.1  15.9  17.5  20.0  22.7  5  4.5  8.1  9.0  12.2  17.7  20.9  22.2  25.4  29.5  6  3.6  5.0  6.1  8.1  13-1  15.0  16.8  18.6  20.4  7  4.3  5.4  6.5  8.4  12.2  14.0  16.3  17.5  20.4  23.6  8  4.7  6.8  8.1  11.3  14.0  19.0  20.4  23.1  26.8  29.0  9  4.5  7.2  9.0  11.8  15.4  16.8  19.0  21.7  23.6  27.2  10  4.9  7.7  9.0  12.2  15.4  17.7  19.0  21.3  26.3  28.1  11  4.0  6.5  8.4  11.5  16.3  19.0  23.1  26.8  23.6  Average  4.0  6.2  7.5  9.7  17.4  19-4  22.2  12.2 15.0 12.2  14.0  13.0 15.0  24.8  105  TABLE A-10 EXPERIMENT II EWES PLASMA UREA N. (mg. urea N/100 ml.) UREA  NO. OF ANIMALS  • -r  1st  2nd  3rd  Weeks of Lac 4th 5th  1  27.9  40.1  34.5  20.1  41.8  15.5  27.9  35.6  2  34.1  20.1  33.3  34-1  24.8  18.6  34.1  41.8  3  29.4  35.8  31.1  38.7  62.0  38.4  34.3  35.6  4  38.7  26.3  39.5  44.9  62.0  35.6  43.4  46.5  5  34-1  38.9  28.2  23.2  26.3  49.6  38.7  44.9  6  29.4  32.5  36.4  37.2  46.8  33.3  31.0  39.3  7  21.7  35.6  39.3  37.2  "37.2  39.3  32.5  31.3  8  27.1  34.2  31.0  31.0  62.0  27.1  30.2  35.6  9  34.4  37.2  49.6  38.9  62.0  38.4  33.3  41.8  Average  30.7  33.4  35.8  33.9  47.2  32.8  33.9  -  6th  7th  8th  39.1  106  TABLE A-10 EXPERIMENT II EWES PLASMA UREA N. (mg. urea N/lOO ml.) SOYBEAN AND UREA  . OF MAIS  1st  2nd  3rd  Weeks of Lactat ion 5th 4th 6th  7th  1  23,2  19.6  . 18.6  20.9  45.4  20.9  14.6  24.8  2  19.3  36.4  37.2  41.8  34.8  35.6  27.1  34.1  3  27.1  27.1  24.8  24.8  58.1  26.3  37.2  36.4  4  27.9  33.3  15.5  10.8  31.0  16.3  24.0  27.9  5  21.7  33.3  21.7  24.0  55.8  20.9  23.2  31.0  6  17.0  31.3  40.3  29.4  55.8  39.3  24.8  41.8  7  23.2  34.1  34.1  28.0  49.6  30.2  24.8  26.3  8  29.4  23.2  21.7  20.1  43.7  34.1  41.8  41.8  9  24.0  24.8  35.6  28.0  31.1  27.1  18.6  38.7  Average  23.7  29.2  27.7  25.3  45.0  27.8  27.0  33.6  8th  107  TABLE A-10 EXPERIMENT II  EWES PLASMA UREA N. (mg. urea N/lOO ml.)  SOYBEAN . OF EMALS  1st  2nd  3rd  1  27.9  31.0  2  24.0  3  -Weeks of l a c t a t i o n - —  —____  4th  5th  6th  7th  8th  28.0  31.0  31.0  31.0  19.6  25.7  31.0  21.7  24.6  31.0  24.8  13.9  24.8  26.3  31.0  24.8  17.8  31.0  31.0  21.7  30.0  4  29.7  28.0  31.0  31.0  31.0  26.6  18.6  26.3  5  23.2  27.9  27.9  23.2  31.0  31.0  21.7  27.0  6  21.7  23.2  27.9  29.4  27.2  27.4  24.8  29.4  7  30.2  31.0  31.0  31.0  31.0  31.0  18.4  29.4  8  20.1  24.8  31.0  31.0  31.0  24.8  15.5  24.8  9  31.0  ,31.0  31.0  25.1  31.0  31.0  17.0  26.3  Average  26.0  28.9  28.2  27.1  30.5  28.7  19.0  27.1  ,  108 TABLE A-11 EXPERIMENT II EWES MILK UREA N (MG. UREA N/lOO ML.) Weeks of Lactation NO. OF ANIMALS  1st  2nd  1  5.1  2  1.1  . 3  0.1  Average  * 3rd  4th  5th  6th  7th  8th  10.0  1.0  5.0  1.1  5.0  3.0  2.5  0.8  3.2  0.0  0.0  3.0  4.0  1.5  5.3  2.0  2.1  0.0  0.0  1.6  2.2  2.1  5.3  2.0  2.3  0.3  2.6  2.8  2.0  1  0.0  3.3  0.7  0.0  0.0  2.0  2.5  5.0  2  0.5  6,5  9.5  2.5  2.5  4.7  4.5  7.0  . 3...  0.1  4.6  1.3  0.0  1.5  0.0  6.7  6.5  Average  0.2  4.8  3.8  0.8  1.3  2.2  4.5  6.1  1  3.1  11.6  4.0  9.0  4.7  4.1  4.2  4.0  2  1.5  6.0  0.7  4.5  0.7  4.5  5.5  7.0  3  6.0  5.1  Dead  Average  3.5  7.5  2.3  6.7  2.7  4.3  4.8  5.5  RATION  Soybean  Soybean & Urea  Urea  109 TABLE A12 EXPERIMENT  II  DRY MATTER DIGESTIBILITY OF WEANED LAMBS  RATION  ANIMALS  TOTAL D.M. INTAKE FOR 5 DAYS  Soybean  1  4529  1875  2654  58.6  2  4329  1692  2637  60.9  Average  4429  1783  2645  59.7  1  4529  2390  2139  47.2  2  4192  1251  29a  70.1  Average  4360  1820  2540  58.6  1  3264  1284  1980  60.6  2  4128  1556  2572  62.3  Average  3696  1420  2276  61.4  NO. OF  Soybean & Urea  Urea  TOTAL D.M. OUTGO FOR •;; 5 DAYS  TOTAL D.M. DIGESTED  %. D. M. DIGESTED  TABLE A-13 EXPERIMENT I I N. DIGESTED AND RETAINED BY WEANED LAMBS  RATION  NO. OF ANIMALS  N. INTAKE FOR 5 DAYS g  ; V  TOTAL Ni LOST IN FAECES FOR 5 DAYS g  TOTAL N. DIGESTED FOR 5.DAYS g  DIGESTION COEFFICIENT PERCENT  %  TOTAL N. LOST IN URINE FOR 5 DAYS g  .....  Soybean  Urea  N. RETAINED N.DIGESTED .%  1  45.2  20.0  25.2  55.7  4.0  24.0  21.2  84.1  2  43.2  16.3  26.9  62.2  5.0  21.3  21.9  80.7  44.2  18.1  26.0  58.9  4.5  22.6  21.5  82.4  1  45.2  15.9  29.3  64.8  7.9  23.8  21.4  73.0  2  41.8  13.8  28.0  66.9  7.5  21.3  20.5  73.2  43.5  14.8  28.6  65.8  7.7  22.5  20.9  73.1  1  32.5  5.4  27.1  83.3  10.2  15.6  16.9  62.3  2  41.2  10.1  31.1  75.4  10.9  21.0  20.2  64.9  36.8  7.7  29.1  79.3  10.5  18.3  18.5  63.6  Average Soybean  TOTAL N. TOTAL N. LOST RETAINED FOR DURING 5 DAYS 5 DAYS (faeces g & urine)  Average  Urea Average  TABLE A - H  LAMBS PLASMA  KO. OF ANIMALS  1  UREA  2  B  (MG i UREA K/lQQ ML,)  3  ,  4  RATION  1  15.9  26.0  27.0  38.0'  2  41.0  41.5  4380  24,0  3  20.0  28.0  29.0  24.0  4  23.0  25.9  25.9  24.0  5  32.6  40.0  40.0  30.0  Average  26.3  32.2  32,5  27.2  1  18.0  22*1  24.0  26.0  2  24.0  29.5  29,5  20.0,  Soybean  3  • 20.1  ,28.1  29.0  21.5  .  4  20.0  29.5  28,5  5  16.5  ,29.5  29,5  Average  i.9.7  27.7  28.1  22.7  1  18.0  28.5  29.0  20.0  2  23.5  25.0  28.0  20.0  3  17.0  20.1  20.0  20*0  4  23.0  29.0  30.0  20.1  5  24.2  27.7  27.9  20.1  Average  21.1  26.6  26,9  20.0  ,  24.0 4  Soybean  Urea  22.0  Urea  '  

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