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Effects of feeding level from 20 to 45 kg on the performance and carcass composition of pigs grown to 90 kg live weight
Livestock Production Science, 10 (1983) 265--272
265
Elsevier Science Publishers B.V., Amsterdam - - P r i n t e d in The Netherlands
EFFECTS OF FEEDING LEVEL FROM 20 TO 45 kg ON THE PERFORMANCE AND CARCASS COMPOSITION OF PIGS GROWN TO 90 kg LIVE WEIGHT
R.G. CAMPBELL, M.R. T A V E R N E R and D.M. CURIC
Animal Research Institute, Princes Highway, Werribee, Victoria 3030 (Australia) (Accepted 30 November 1982)
ABSTRACT Campbell, R.G., Taverner, M.R. and Curic, D.M., 1983. Effects of feeding level from 20 to 45 kg on the performance and carcass composition of pigs grown to 90 kg live weight. Livest. Prod. Sci., 10: 265--272. Twenty-seven female pigs were used to study the effects of three levels of feeding (low, moderate and ad libitum) from 20 to 45 kg on growth performance and carcass composition to 90 kg live weight. During the live weight phase 20 to 45 kg, raising the level of feeding increased growth rate (P < 0.05), body fat and carcass fat measurements (P < 0.05), but reduced body water (P < 0.05). Subsequent to 45 kg, pigs previously fed at the lowest level grew more rapidly (P < 0.05) and had lower (P < 0.05) feed conversion ratio (FCR) than pigs from either of the other feeding treatments to 45 kg and at 90 kg were leaner (P < 0.05) than pigs offered feeding ad libitum between 20 and 45 kg. For total test (20--90 kg), pigs fed at the lowest level to 45 kg grew at a slower rate (P < 0.05), but had a lower FCR (P < 0.05) than pigs from the other two feeding treatments before 45 kg. Pigs subjected to the moderate feed restriction between 20 and 45 kg grew at a similar rate from 20 to 90 kg, but had a lower FCR (P < 0.05) than those offered feeding ad libitum before 45 kg.
INTRODUCTION
The growth performance of pigs between 20 and 90 kg live weight is known to be influenced by nutrition prior to 20 kg (Elsley, 1963; Nielsen, 1964; Campbell and Biden, 1978; R.G. Campbell and A.C. Dunkin, un published data, 1980). For example, Elsley (1963) and Nielsen (1964) reported that pigs fed restrictively from 5 to 20 kg subsequently grew more rapidly than those offered feeding ad libitum prior to 20 kg. Both authors also suggested that level of feeding prior to 20 kg affected carcass fat measurements at 90 kg live weight. However, the influence of feeding level between 20 and 45 kg live weight on the growth performance and carcass characteristics of the finisher pig (45--90 kg) is not as well established; although the data of Prince et al. (1981) indicate that subsequent to 45 kg the pig is capable of compensatory
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© 1983 Elsevier Science Publishers B.V.
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growth following restricted feeding during the grower phase. Previous research at this centre (R.G. Campbell, M.R. Taverner and D.M. Curic, unpublished data, 1983) has shown that level o f feeding between 20 and 45 kg has a marked effect on growth performance and b o d y composition at the latter weight. The experiment reported here was designed to study the influence of feeding level during this phase of production on the performance and carcass composition of pigs grown to 90 kg live weight. MATERIALS AND METHODS
Animals and design Twenty-seven female pigs (3/4 Large White X 1/4 Berkshire) weaned at seven weeks of age were allocated, as their individual live weights reached 20 kg, among three feeding treatments to 45 kg. At the latter weight, three pigs from each treatment group were killed and the remainder were fed a common diet in restricted amounts and were killed at 90 kg live weight. Pigs were allocated to the three treatment groups according to a randomized block design.
Diets and feeding The composition of the diets fed prior and subsequent to 45 kg is given in Table I. Diet A was fed at a low and moderate level of intake and offered ad libitum from 20 to 45 kg live weight. The low and moderate levels of feeding were based on scales which allowed 793 and 1123 g/pig/day at 20 kg and increased linearly to 1462 and 2069 g/pig/day at 45 kg live weight, respectively. The feed consumption of pigs offered the diet ad libitum was recorded daily. Between 45 and 90 kg live weight all pigs were fed diet B (Table I) according to a scale which increased from 1.88 kg/pig/day at 45 kg to a maximum of 2.97 kg/pig/day at 77 kg live weight. The diets were offered as a dry mash and during both live weight phases feeding was twice daily at 0800 and 1600 h. Proximate analysis of the diets was determined using the methods outlined by the Association of Official Analytical Chemists (A.O.A.C., 1965). Dietary lysine was calculated from lysine analysis of the major ingredients using the methods of F o x (1971). The digestible energy (DE) content of the diets was determined in two metabolism trials each involving four entire male pigs. The feeding and collection procedures adopted during each of the metabolism trials were the same as those described by Campbell and Biden {1978).
Housing and management All pigs were housed in individual pens in an insulated, b u t unheated building. Between weaning and the c o m m e n c e m e n t of the experimental
267 TABLE I C o m p o s i t i o n o f e x p e r i m e n t a l diets (g/kg air dry diet) Diet A 20--45 kg
B 45-- 90 kg
Ingredients Wheat Barley S o y a bean meal S k i m milk p o w d e r Meat and bone meal Blood meal Salt Vitamin mineral p r e m i x *
723 -170 50 50 -2 5
400 400 80 -80 35 -5
Analysis Crude protein (g kg -1) Lysine (g kg -1 ) DE (MJ kg -1)
209 10.5 14.5
186 7.6 13.4
*Provided the following nutrients (per kg air-dry diet): vitamins, retinol 1.15 rag, cholecalciferol 8.3 mg, D - a - t o c o p h e r o l 22 rag, m e n a d i o n e 660 rag, riboflavin, 3.3 rag, niacin 16.5 rag, p a n t o t h e n i c acid 5.5 rag, p y r i d o x i n e 1.1 rag, biotin 5 rag, choline 1100 rag, c y a n o c o b a l a m i n 17 ug, minerals, Fe 88 rag, Zn 55 rag, Mn 22 rag, Cu 6.6 rag, I 0.22 mg, Se 0.1 rag.
treatments at 20 kg live weight all pigs were offered a c o m m o n diet ad libiturn and were weighed daily. After 20 kg the pigs were weighed weekly and each pig's daily feed allowance for the following week was adjusted accordingly.
Slaughter procedures For pigs killed at 45 kg live weight, the e m p t y gut and all internal organs were weighed together and stored at - 2 0 ° C . The eviscerated carcass was chilled overnight and the following morning linear fat measurements were taken over the " e y e muscle" at P2 (6.0 cm from mid-line at the level of the last rib) and along the mid-line, at the rump (anterior to the m. gluteus medius), mid-back (between the seventh and eighth vertebrae forward of the sacrum) and at the point of m a x i m u m fat thickness over the shoulder. The eviscerated carcass was then weighed and stored at - 2 0 ° C along with the e m p t y gut and internal organs. The frozen material was ground to a fine paste with a commercial butcher's mincer, mixed and sub-sampled for chemical analysis. The same procedure was adopted for pigs killed at 90 kg live weight except t h a t the gastro-intestinal tract and the internal organs were discarded and only the right side of each carcass was used for chemical analysis.
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Statistical analysis T r e a t m e n t effects were assessed by analysis o f variance. RESULTS Th e results for growth p e r f o r m a n c e during the live weight periods, 20 to 45, 45 to 90 and 20 to 90 kg are given in Table II. During the live weight period 20 to 45 kg each increase in level o f feeding improved (P < 0.05) growth rate, but had no significant effect on the feed conversion ratio (FCR). Between 45 and 90 kg live weight t he pigs previously fed at the lowest level exhibited m o r e rapid and efficient growth (P < 0.05) t han pigs from the ad libitum feeding group. T he growth rate and FCR o f pigs given the m od er ate level of feeding bef or e 45 kg were intermediate with those from the low and ad libitum fed groups. Fo r the whole p r o d u c t i o n period (20 t o 90 kg), pigs fed at the lowest level b e f o r e 45 kg grew at a slower rate (P < 0.05), but had a lower FCR (P < 0.05) th an either the ad libitum fed group or those subjected to the m o d e r a t e feed restriction between 20 and 45 kg. FCR for pigs fed at the m o d e r a t e level f r o m 20 to 45 kg was also lower (P < 0.05) than t hat o f pigs offered feeding ad libitum before 45 kg. TABLE II Effects of feeding level from 20 to 45 kg on the average daily gain and feed conversion ratio (FCR) of pigs growing between 20 and 45, 45 and 90 and 20 and 90 kg live weight Live weight period
Level of feeding (20--45 kg)
LSD (P < o.05)
Low
Medium
Ad libitum
20--45 kg Daily gain (g) FCR
446 a 2.47 a
639 b 2.43 a
822 c 2.48 a
61.8 0.18
45--90 kg Daily gain (g) FCR
802 a 2.93 a
736 ab 3.18 b
702 b 3.32 b
69.7 0.20
20--90 kg Daily gain (g) FCR
630a 2.80 a
686 b 3.00 b
712 b 3.22 c
49.5 0.18
In this and Table III, within rows, treatment means followed by different superscript letters are significantly different (P < 0.05).
Carcass characteristics The results f o r b o d y c om pos i t i on and carcass fat measurements at 45 and 90 kg live weight are presented in Table III. Each increase in t h e level o f
269 feeding b e t w e e n 20 a n d 45 kg live w e i g h t increased b o d y f a t a n d carcass fat m e a s u r e m e n t s (P < 0 . 0 5 ) b u t r e d u c e d b o d y w a t e r (P < 0 . 0 5 ) at t h e l a t t e r weight. A t 90 kg live w e i g h t pigs fed at t h e l o w e s t level b e t w e e n 20 and 45 kg c o n t a i n e d less f a t (P < 0 . 0 5 ) in t h e carcass a n d h a d s m a l l e r (P < 0 . 0 5 ) linear f a t m e a s u r e m e n t s t h a n pigs o f f e r e d f e e d i n g ad l i b i t u m f r o m 20 t o 45 kg live weight. Level o f f e e d i n g b e f o r e 45 kg h a d n o significant e f f e c t o n b o d y p r o t e i n or ash at e i t h e r 45 or 90 kg. TABLE III Effects of level of feeding from 20 to 45 kg on the body composition and carcass characteristics of pigs at 45 kg live weight (LW) and on carcass composition and carcass characteristics at 90 kg LW Effects at (kg LW) 45 Body composition (g/kg) Water Protein Fat Ash Carcass fat measurements Av. back fat (ram) P~ (ram) 90 Carcass composition (g/kg) Water Protein Fat Ash Carcass fat measurements Av. back fat (mm) P2 (ram)
Level of feeding (20--45 kg) Low
Medium
Ad libitum
681 a 172 a 184 a 26 a
543 b 174 a 2535 30 a
500 c 167 a 306 c 27 a
15.0 a 10.4 a 467 a 158 a 342 a 33 a 26.4 a 21.4 a
17.9 ab 14.25 454 ab 157 a 357 ab 32 a 28.9 ab 23.7 ab
21.05 17.2 b 426 c 152 a 388 b 34 a 31.25 24.5 b
LSD (P < 0.05)
18.9 8.6 15.8 3.6 3.6 3.5 16.0 12.2 37.4 3.2 4.3 2.4
DISCUSSION D u r i n g t h e live w e i g h t p h a s e , 20 t o 45 kg, t h e average daffy feed i n t a k e o f pigs o n t h e l o w (1.01 k g / d a y ) and m e d i u m (1.56 k g / d a y ) feeding scales was a p p r o x i m a t e l y 54 a n d 76%, r e s p e c t i v e l y , o f t h a t c o n s u m e d b y pigs o f f e r e d t h e d i e t ad l i b i t u m ( 2 . 0 4 k g / d a y ) . T h e results s h o w e d t h a t r e s t r i c t i n g feed int a k e b e f o r e 45 kg d e p r e s s e d g r o w t h r a t e at r e d u c e d b o d y f a t a n d carcass f a t m e a s u r e m e n t s at t h e l a t t e r weight, t h e e f f e c t s b e i n g similar t o t h o s e r e p o r t ed b y Davies a n d L u c a s ( 1 9 7 2 ) f o r pigs g r o w i n g f r o m 20 t o 4 0 kg. H o w e v e r , s u b s e q u e n t t o 45 kg, pigs p r e v i o u s l y f e d restrictively e x h i b i t e d m o r e r a p i d a n d e f f i c i e n t g r o w t h t h a n t h o s e o f f e r e d t h e diet ad l i b i t u m b e f o r e 45 kg. T h e
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results also indicated that the magnitude of the improved growth performance was positively related to the severity of the previous restriction. Similar findings have been reported for grower-finisher pigs subjected to feed restriction between weaning at 3--5 weeks of age and 20--25 kg live weight (e.g., Elsley, 1963; Nielsen, 1964; G~deken et al., 1979). The design of the present experiment did not permit the partition of energy between individual components of the e m p t y b o d y to be determined for the live weight phase 45 to 90 kg. However, previous research with younger pigs (Campbell and Dunkin, 1980) showed that pigs subjected to a feed restriction in early life subsequently deposited protein and fat at a faster rate than pigs fed more generously during early development. These latter results and those of Gray and McCracken (1979) indicate that restricting feed during one stage of development may lower the animals' energy requirement for maintenance during subsequent development. The results of the present experiment also showed that pigs subjected to the severest feed restriction between 20 and 45 kg were still leaner at 90 kg and over the whole production period (20 to 90 kg) used feed 15% more efficiently than those offered feeding ad libitum to 45 kg. Nevertheless, the improvement in growth performance exhibited subsequent to 45 kg by these animals was of insufficient magnitude to overcome the considerable age difference at 45 kg between this treatment group and pigs given the diet ad libitum between 20 and 45 kg. Consequently, pigs fed at the lowest level before 45 kg grew at a slower rate between 20 and 90 kg and at the latter weight were, on average, 13 days older than those fed ad libitum before 45 kg. Clearly this extension in time to reach eventual slaughter weight would have to be balanced against the improvement in carcass quality and feed utilization in any practical consideration of these two feeding strategies for the growing pig. On the other hand, the compensatory growth response exhibited between 45 and 90 kg by pigs fed at the moderate level before 45 kg, although less pronounced than that for pigs previously fed at the lowest level, was more complete and between 20 and 90 kg these animals grew at a similar rate, but used feed 7.9% more efficiently than those offered feeding ad libitum from 20 to 45 kg. Pigs fed at the moderate level to 45 kg also exhibited similar carcass composition and carcass quality characteristics at 90 kg as those offered feeding ad libitum before 45 kg. These findings are in close agreement with the results o f Prince et al. (1981). The latter authors reported that a two or four week feed restriction (85% of ad libitum) imposed during the grower phase had no effect on the daily gain of pigs grown from 25 to 99 kg or on carcass characteristics at latter weight, b u t improved, significantly, the efficiency of feed utilization relative to that of pigs offered feeding ad libit u m throughout. The results of the present experiment and those of Prince et al. (1981) indicate that relative to pigs given diets ad libitum a degree of feed restriction in the live weight phase 20 to 45 kg may improve feed conversion effi-
271
ciency in animals grown to bacon weight without adversely affecting age of eventual slaughter. Our data also show that level of feeding during the grower phase influences carcass quality of 90 kg, but suggest that the degree of feed restriction between 20 and 45 kg required to effect improvement in carcass quality at 90 kg may result in an unacceptable increase in age at eventual slaughter. Nevertheless, the marked improvement in feed conversion efficiency exhibited between 20 and 90 kg by pigs subjected to the severest feed restriction before 45 kg in the current experiment suggests that this area of the grower-finisher pig's nutrition warrants further research. ACKNOWLEDGEMENTS
The authors thank Mr. A. McKay and N. Follett for their expert technical assistance and Mr. R. Jardine for the statistical analysis of the data. The work was supported by a grant from the Australian Pig Industry Research Committee.
REFERENCES Association of Official Analytical Chemists, 1965. Official Methods of Analysis. 10th edn. Assoc. Off. Anal. Chem., Washington, DC. Campbell, R.G. and Biden, R.S., 1978. The effect of protein nutrition between 5.5 and 20 kg live weight on the subsequent performance and carcass quality of pigs. Anita. Prod., 27: 223--228. Campbell, R.G. and Dunkin, A.C., 1980. Effect of nutrition in early life on subsequent growth and body composition. Proc. Aust. Soc. Anim. Prod., 13: 131--133. Davies, J.L. and Lucas, I.A.M., 1972. Responses to variations in dietary energy intakes by growing pigs. Anim. Prod., 15: 117--125. Elsley, F.W.H., 1963. Studies of growth and development in young pigs. Part II. A comparison of the performance to 200 lb. of pigs reared along different growth curves to 56 days of age. J. Agric. Sci., 61 : 243--251. Fox, M., 1971. Nutritional evaluation of meat and bone meal. Victorian Department of Agriculture, Division of Agricultural Chemistry Melbourne, Victoria. Divisional Report no. 2, 15 pp. G~'deken, D., BShme, H. and Oslage, H.J., 1979. Restriction of feed intake and compensatory growth responses in pigs. Eur. Assoc. Anim. Prod., Publ. no. 26, pp. 407-410. Gray, R. and McCracken, K.J., 1979. Effect of confinement in a respiration chamber and changes in temperature and plane of nutrition on heat production of 25 kg pigs. J. Agric. Sci., 95: 123--133. Nielsen, H.E., 1964. Effects in bacon pigs of differing levels of nutrition to 20 kg body weight. Anita. Prod., 6: 301--308. Prince, T.J., Kuhlers, D.L. and Jungst, S.B., 1981. Compensatory responses to feed restriction during the growing period. J. Anita. Sci., Abstr., 51: 14.
272 RESUME Campbell, R.G., Taverner, M.R. et Curic, D.M., 1983. Effets du niveau d'alimentation de 20 ~ 45 kg sur les performances et la composition de la carcasse de porcs ~lev~s jusqu'au poids vif de 90 kg. Livest. Prod. Sci., 10:265--272 (en anglais). Vingt-sept porcs femelles ont dt~ utilisds pour ~tudier les effets de trois niveaux d'alimentation (bas, m o y e n et ad libitum) entre 20 et 45 kg sur les performances de croissance et la composition de la carcasse ~ 90 kg de poids vif. Pendant la phase de 20 ~ 45 kg, l'~l~vation du niveau d'alimentation augmente la vitesse de croissance (P < 0,05), les graisses corporelles et les mesures d'adiposit~ de la carcasse (P < 0,05) mais r~duit la teneur en eau corporelle (P < 0,05). Apr~s 45 kg, les porcs ayant re~u auparavant le niveau d'alimentation le plus bas avaient une croissance plus rapide (P < 0,05) et un indice de consommation (FCR) plus faible (P < 0,05) que les porcs soumis aux deux autres traitements avant 45 kg, et ~taient plus maigres ~ 90 kg (P < 0,05) que ceux nourris ~ volont~ entre 20 et 45 kg. Sur toute la p~riode de l'~tude (20--90 kg), les animaux les plus rationn~s avant 45 kg avaient la croissance plus lente (P < 0,05) mais l'indice de consommation plus faible (P < 0,05) que ceux des deux autres lots. Les porcs soumis ~ une restriction alimentaire mod~r~e entre 20 et 45 kg avaient la m ~ m e vitesse de croissance entre 20 et 90 kg que ceux nourris ad libitum pendant cette p~riode, mais leur indice de consommation ~tait inf~rieur (P < 0,05).
KURZFASSUNG Campbell, R.G., Taverner, M.R. und Curic, D.M., 1983. Einfluss des Ffitterungsniveau im Mastabschnitt 20 bis 45 kg auf die Leistung und SchlachtkSrperzusammensetzung yon Schweinen -- gem~istet bis 90 kg Lebendgewicht. Livest. Prod. Sci., 10:265--272 (auf englisch). Ffir die Untersuchung der Auswirkungen von drei Ffitterungsniveaus (gering, m~issig und ad libitum) im Mastabschnitt von 20 bis 45 kg auf Wachstumsleistung und Schlachtk6rperzusammensetzung bis zu einem Lebendgewicht yon 90 kg wurden 27 weibliche Tiere herangezogen. Wurde das Ffitterungsniveau in der Lebendgewichtsphase 20 bis 45 kg erhSht, so stiegen die Wachstumsrate (P < 0,05) sowie die Masse ffirKSrper und Auflagefett (P < 0,05) aber das KSrperwasser reduzierte sich (P <~ 0,05). Nach Erreichen des Gewichtsabschnittes yon 45 kg, wuchsen Schweine, die vorher auf d e m niedrigen Niveau geffittert wurden, schneller (P <~ 0,05) und hatten eine giinstigere Futterverwertung als Schweine der anderen beiden Ffitterungsniveaus; darfiberhinaus waxen diese Schweine dann mit 90 kg magerer (P < 0,05) als die, die im Mastabschnitt 20--45 kg ad libitum geffittertwurden. Eine Gesamtanalyse (20--90 kg) ergab, dass die Schweine mit d e m geringen Ffitterungsniveau bis z u m 45 kg-Gewicht zwar eine geringere Wachstumsrate (P < 0,05) aber auch eine gfinstigere Futterverwertung hatten als die Tiere der beiden anderen Ffitterungsniveaus. Schweine des mittleren Ffitterungsniveaus zeigten fiber den Gewichtsabschnitt 20-90 kg ein ~ihnliches Wachstum, hatten aber eine gfinstigere Futterverwertung als die ad libitum geffitterten Tiere.
265
Elsevier Science Publishers B.V., Amsterdam - - P r i n t e d in The Netherlands
EFFECTS OF FEEDING LEVEL FROM 20 TO 45 kg ON THE PERFORMANCE AND CARCASS COMPOSITION OF PIGS GROWN TO 90 kg LIVE WEIGHT
R.G. CAMPBELL, M.R. T A V E R N E R and D.M. CURIC
Animal Research Institute, Princes Highway, Werribee, Victoria 3030 (Australia) (Accepted 30 November 1982)
ABSTRACT Campbell, R.G., Taverner, M.R. and Curic, D.M., 1983. Effects of feeding level from 20 to 45 kg on the performance and carcass composition of pigs grown to 90 kg live weight. Livest. Prod. Sci., 10: 265--272. Twenty-seven female pigs were used to study the effects of three levels of feeding (low, moderate and ad libitum) from 20 to 45 kg on growth performance and carcass composition to 90 kg live weight. During the live weight phase 20 to 45 kg, raising the level of feeding increased growth rate (P < 0.05), body fat and carcass fat measurements (P < 0.05), but reduced body water (P < 0.05). Subsequent to 45 kg, pigs previously fed at the lowest level grew more rapidly (P < 0.05) and had lower (P < 0.05) feed conversion ratio (FCR) than pigs from either of the other feeding treatments to 45 kg and at 90 kg were leaner (P < 0.05) than pigs offered feeding ad libitum between 20 and 45 kg. For total test (20--90 kg), pigs fed at the lowest level to 45 kg grew at a slower rate (P < 0.05), but had a lower FCR (P < 0.05) than pigs from the other two feeding treatments before 45 kg. Pigs subjected to the moderate feed restriction between 20 and 45 kg grew at a similar rate from 20 to 90 kg, but had a lower FCR (P < 0.05) than those offered feeding ad libitum before 45 kg.
INTRODUCTION
The growth performance of pigs between 20 and 90 kg live weight is known to be influenced by nutrition prior to 20 kg (Elsley, 1963; Nielsen, 1964; Campbell and Biden, 1978; R.G. Campbell and A.C. Dunkin, un published data, 1980). For example, Elsley (1963) and Nielsen (1964) reported that pigs fed restrictively from 5 to 20 kg subsequently grew more rapidly than those offered feeding ad libitum prior to 20 kg. Both authors also suggested that level of feeding prior to 20 kg affected carcass fat measurements at 90 kg live weight. However, the influence of feeding level between 20 and 45 kg live weight on the growth performance and carcass characteristics of the finisher pig (45--90 kg) is not as well established; although the data of Prince et al. (1981) indicate that subsequent to 45 kg the pig is capable of compensatory
0301-6226/83/$03.00
© 1983 Elsevier Science Publishers B.V.
266
growth following restricted feeding during the grower phase. Previous research at this centre (R.G. Campbell, M.R. Taverner and D.M. Curic, unpublished data, 1983) has shown that level o f feeding between 20 and 45 kg has a marked effect on growth performance and b o d y composition at the latter weight. The experiment reported here was designed to study the influence of feeding level during this phase of production on the performance and carcass composition of pigs grown to 90 kg live weight. MATERIALS AND METHODS
Animals and design Twenty-seven female pigs (3/4 Large White X 1/4 Berkshire) weaned at seven weeks of age were allocated, as their individual live weights reached 20 kg, among three feeding treatments to 45 kg. At the latter weight, three pigs from each treatment group were killed and the remainder were fed a common diet in restricted amounts and were killed at 90 kg live weight. Pigs were allocated to the three treatment groups according to a randomized block design.
Diets and feeding The composition of the diets fed prior and subsequent to 45 kg is given in Table I. Diet A was fed at a low and moderate level of intake and offered ad libitum from 20 to 45 kg live weight. The low and moderate levels of feeding were based on scales which allowed 793 and 1123 g/pig/day at 20 kg and increased linearly to 1462 and 2069 g/pig/day at 45 kg live weight, respectively. The feed consumption of pigs offered the diet ad libitum was recorded daily. Between 45 and 90 kg live weight all pigs were fed diet B (Table I) according to a scale which increased from 1.88 kg/pig/day at 45 kg to a maximum of 2.97 kg/pig/day at 77 kg live weight. The diets were offered as a dry mash and during both live weight phases feeding was twice daily at 0800 and 1600 h. Proximate analysis of the diets was determined using the methods outlined by the Association of Official Analytical Chemists (A.O.A.C., 1965). Dietary lysine was calculated from lysine analysis of the major ingredients using the methods of F o x (1971). The digestible energy (DE) content of the diets was determined in two metabolism trials each involving four entire male pigs. The feeding and collection procedures adopted during each of the metabolism trials were the same as those described by Campbell and Biden {1978).
Housing and management All pigs were housed in individual pens in an insulated, b u t unheated building. Between weaning and the c o m m e n c e m e n t of the experimental
267 TABLE I C o m p o s i t i o n o f e x p e r i m e n t a l diets (g/kg air dry diet) Diet A 20--45 kg
B 45-- 90 kg
Ingredients Wheat Barley S o y a bean meal S k i m milk p o w d e r Meat and bone meal Blood meal Salt Vitamin mineral p r e m i x *
723 -170 50 50 -2 5
400 400 80 -80 35 -5
Analysis Crude protein (g kg -1) Lysine (g kg -1 ) DE (MJ kg -1)
209 10.5 14.5
186 7.6 13.4
*Provided the following nutrients (per kg air-dry diet): vitamins, retinol 1.15 rag, cholecalciferol 8.3 mg, D - a - t o c o p h e r o l 22 rag, m e n a d i o n e 660 rag, riboflavin, 3.3 rag, niacin 16.5 rag, p a n t o t h e n i c acid 5.5 rag, p y r i d o x i n e 1.1 rag, biotin 5 rag, choline 1100 rag, c y a n o c o b a l a m i n 17 ug, minerals, Fe 88 rag, Zn 55 rag, Mn 22 rag, Cu 6.6 rag, I 0.22 mg, Se 0.1 rag.
treatments at 20 kg live weight all pigs were offered a c o m m o n diet ad libiturn and were weighed daily. After 20 kg the pigs were weighed weekly and each pig's daily feed allowance for the following week was adjusted accordingly.
Slaughter procedures For pigs killed at 45 kg live weight, the e m p t y gut and all internal organs were weighed together and stored at - 2 0 ° C . The eviscerated carcass was chilled overnight and the following morning linear fat measurements were taken over the " e y e muscle" at P2 (6.0 cm from mid-line at the level of the last rib) and along the mid-line, at the rump (anterior to the m. gluteus medius), mid-back (between the seventh and eighth vertebrae forward of the sacrum) and at the point of m a x i m u m fat thickness over the shoulder. The eviscerated carcass was then weighed and stored at - 2 0 ° C along with the e m p t y gut and internal organs. The frozen material was ground to a fine paste with a commercial butcher's mincer, mixed and sub-sampled for chemical analysis. The same procedure was adopted for pigs killed at 90 kg live weight except t h a t the gastro-intestinal tract and the internal organs were discarded and only the right side of each carcass was used for chemical analysis.
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Statistical analysis T r e a t m e n t effects were assessed by analysis o f variance. RESULTS Th e results for growth p e r f o r m a n c e during the live weight periods, 20 to 45, 45 to 90 and 20 to 90 kg are given in Table II. During the live weight period 20 to 45 kg each increase in level o f feeding improved (P < 0.05) growth rate, but had no significant effect on the feed conversion ratio (FCR). Between 45 and 90 kg live weight t he pigs previously fed at the lowest level exhibited m o r e rapid and efficient growth (P < 0.05) t han pigs from the ad libitum feeding group. T he growth rate and FCR o f pigs given the m od er ate level of feeding bef or e 45 kg were intermediate with those from the low and ad libitum fed groups. Fo r the whole p r o d u c t i o n period (20 t o 90 kg), pigs fed at the lowest level b e f o r e 45 kg grew at a slower rate (P < 0.05), but had a lower FCR (P < 0.05) th an either the ad libitum fed group or those subjected to the m o d e r a t e feed restriction between 20 and 45 kg. FCR for pigs fed at the m o d e r a t e level f r o m 20 to 45 kg was also lower (P < 0.05) than t hat o f pigs offered feeding ad libitum before 45 kg. TABLE II Effects of feeding level from 20 to 45 kg on the average daily gain and feed conversion ratio (FCR) of pigs growing between 20 and 45, 45 and 90 and 20 and 90 kg live weight Live weight period
Level of feeding (20--45 kg)
LSD (P < o.05)
Low
Medium
Ad libitum
20--45 kg Daily gain (g) FCR
446 a 2.47 a
639 b 2.43 a
822 c 2.48 a
61.8 0.18
45--90 kg Daily gain (g) FCR
802 a 2.93 a
736 ab 3.18 b
702 b 3.32 b
69.7 0.20
20--90 kg Daily gain (g) FCR
630a 2.80 a
686 b 3.00 b
712 b 3.22 c
49.5 0.18
In this and Table III, within rows, treatment means followed by different superscript letters are significantly different (P < 0.05).
Carcass characteristics The results f o r b o d y c om pos i t i on and carcass fat measurements at 45 and 90 kg live weight are presented in Table III. Each increase in t h e level o f
269 feeding b e t w e e n 20 a n d 45 kg live w e i g h t increased b o d y f a t a n d carcass fat m e a s u r e m e n t s (P < 0 . 0 5 ) b u t r e d u c e d b o d y w a t e r (P < 0 . 0 5 ) at t h e l a t t e r weight. A t 90 kg live w e i g h t pigs fed at t h e l o w e s t level b e t w e e n 20 and 45 kg c o n t a i n e d less f a t (P < 0 . 0 5 ) in t h e carcass a n d h a d s m a l l e r (P < 0 . 0 5 ) linear f a t m e a s u r e m e n t s t h a n pigs o f f e r e d f e e d i n g ad l i b i t u m f r o m 20 t o 45 kg live weight. Level o f f e e d i n g b e f o r e 45 kg h a d n o significant e f f e c t o n b o d y p r o t e i n or ash at e i t h e r 45 or 90 kg. TABLE III Effects of level of feeding from 20 to 45 kg on the body composition and carcass characteristics of pigs at 45 kg live weight (LW) and on carcass composition and carcass characteristics at 90 kg LW Effects at (kg LW) 45 Body composition (g/kg) Water Protein Fat Ash Carcass fat measurements Av. back fat (ram) P~ (ram) 90 Carcass composition (g/kg) Water Protein Fat Ash Carcass fat measurements Av. back fat (mm) P2 (ram)
Level of feeding (20--45 kg) Low
Medium
Ad libitum
681 a 172 a 184 a 26 a
543 b 174 a 2535 30 a
500 c 167 a 306 c 27 a
15.0 a 10.4 a 467 a 158 a 342 a 33 a 26.4 a 21.4 a
17.9 ab 14.25 454 ab 157 a 357 ab 32 a 28.9 ab 23.7 ab
21.05 17.2 b 426 c 152 a 388 b 34 a 31.25 24.5 b
LSD (P < 0.05)
18.9 8.6 15.8 3.6 3.6 3.5 16.0 12.2 37.4 3.2 4.3 2.4
DISCUSSION D u r i n g t h e live w e i g h t p h a s e , 20 t o 45 kg, t h e average daffy feed i n t a k e o f pigs o n t h e l o w (1.01 k g / d a y ) and m e d i u m (1.56 k g / d a y ) feeding scales was a p p r o x i m a t e l y 54 a n d 76%, r e s p e c t i v e l y , o f t h a t c o n s u m e d b y pigs o f f e r e d t h e d i e t ad l i b i t u m ( 2 . 0 4 k g / d a y ) . T h e results s h o w e d t h a t r e s t r i c t i n g feed int a k e b e f o r e 45 kg d e p r e s s e d g r o w t h r a t e at r e d u c e d b o d y f a t a n d carcass f a t m e a s u r e m e n t s at t h e l a t t e r weight, t h e e f f e c t s b e i n g similar t o t h o s e r e p o r t ed b y Davies a n d L u c a s ( 1 9 7 2 ) f o r pigs g r o w i n g f r o m 20 t o 4 0 kg. H o w e v e r , s u b s e q u e n t t o 45 kg, pigs p r e v i o u s l y f e d restrictively e x h i b i t e d m o r e r a p i d a n d e f f i c i e n t g r o w t h t h a n t h o s e o f f e r e d t h e diet ad l i b i t u m b e f o r e 45 kg. T h e
270
results also indicated that the magnitude of the improved growth performance was positively related to the severity of the previous restriction. Similar findings have been reported for grower-finisher pigs subjected to feed restriction between weaning at 3--5 weeks of age and 20--25 kg live weight (e.g., Elsley, 1963; Nielsen, 1964; G~deken et al., 1979). The design of the present experiment did not permit the partition of energy between individual components of the e m p t y b o d y to be determined for the live weight phase 45 to 90 kg. However, previous research with younger pigs (Campbell and Dunkin, 1980) showed that pigs subjected to a feed restriction in early life subsequently deposited protein and fat at a faster rate than pigs fed more generously during early development. These latter results and those of Gray and McCracken (1979) indicate that restricting feed during one stage of development may lower the animals' energy requirement for maintenance during subsequent development. The results of the present experiment also showed that pigs subjected to the severest feed restriction between 20 and 45 kg were still leaner at 90 kg and over the whole production period (20 to 90 kg) used feed 15% more efficiently than those offered feeding ad libitum to 45 kg. Nevertheless, the improvement in growth performance exhibited subsequent to 45 kg by these animals was of insufficient magnitude to overcome the considerable age difference at 45 kg between this treatment group and pigs given the diet ad libitum between 20 and 45 kg. Consequently, pigs fed at the lowest level before 45 kg grew at a slower rate between 20 and 90 kg and at the latter weight were, on average, 13 days older than those fed ad libitum before 45 kg. Clearly this extension in time to reach eventual slaughter weight would have to be balanced against the improvement in carcass quality and feed utilization in any practical consideration of these two feeding strategies for the growing pig. On the other hand, the compensatory growth response exhibited between 45 and 90 kg by pigs fed at the moderate level before 45 kg, although less pronounced than that for pigs previously fed at the lowest level, was more complete and between 20 and 90 kg these animals grew at a similar rate, but used feed 7.9% more efficiently than those offered feeding ad libitum from 20 to 45 kg. Pigs fed at the moderate level to 45 kg also exhibited similar carcass composition and carcass quality characteristics at 90 kg as those offered feeding ad libitum before 45 kg. These findings are in close agreement with the results o f Prince et al. (1981). The latter authors reported that a two or four week feed restriction (85% of ad libitum) imposed during the grower phase had no effect on the daily gain of pigs grown from 25 to 99 kg or on carcass characteristics at latter weight, b u t improved, significantly, the efficiency of feed utilization relative to that of pigs offered feeding ad libit u m throughout. The results of the present experiment and those of Prince et al. (1981) indicate that relative to pigs given diets ad libitum a degree of feed restriction in the live weight phase 20 to 45 kg may improve feed conversion effi-
271
ciency in animals grown to bacon weight without adversely affecting age of eventual slaughter. Our data also show that level of feeding during the grower phase influences carcass quality of 90 kg, but suggest that the degree of feed restriction between 20 and 45 kg required to effect improvement in carcass quality at 90 kg may result in an unacceptable increase in age at eventual slaughter. Nevertheless, the marked improvement in feed conversion efficiency exhibited between 20 and 90 kg by pigs subjected to the severest feed restriction before 45 kg in the current experiment suggests that this area of the grower-finisher pig's nutrition warrants further research. ACKNOWLEDGEMENTS
The authors thank Mr. A. McKay and N. Follett for their expert technical assistance and Mr. R. Jardine for the statistical analysis of the data. The work was supported by a grant from the Australian Pig Industry Research Committee.
REFERENCES Association of Official Analytical Chemists, 1965. Official Methods of Analysis. 10th edn. Assoc. Off. Anal. Chem., Washington, DC. Campbell, R.G. and Biden, R.S., 1978. The effect of protein nutrition between 5.5 and 20 kg live weight on the subsequent performance and carcass quality of pigs. Anita. Prod., 27: 223--228. Campbell, R.G. and Dunkin, A.C., 1980. Effect of nutrition in early life on subsequent growth and body composition. Proc. Aust. Soc. Anim. Prod., 13: 131--133. Davies, J.L. and Lucas, I.A.M., 1972. Responses to variations in dietary energy intakes by growing pigs. Anim. Prod., 15: 117--125. Elsley, F.W.H., 1963. Studies of growth and development in young pigs. Part II. A comparison of the performance to 200 lb. of pigs reared along different growth curves to 56 days of age. J. Agric. Sci., 61 : 243--251. Fox, M., 1971. Nutritional evaluation of meat and bone meal. Victorian Department of Agriculture, Division of Agricultural Chemistry Melbourne, Victoria. Divisional Report no. 2, 15 pp. G~'deken, D., BShme, H. and Oslage, H.J., 1979. Restriction of feed intake and compensatory growth responses in pigs. Eur. Assoc. Anim. Prod., Publ. no. 26, pp. 407-410. Gray, R. and McCracken, K.J., 1979. Effect of confinement in a respiration chamber and changes in temperature and plane of nutrition on heat production of 25 kg pigs. J. Agric. Sci., 95: 123--133. Nielsen, H.E., 1964. Effects in bacon pigs of differing levels of nutrition to 20 kg body weight. Anita. Prod., 6: 301--308. Prince, T.J., Kuhlers, D.L. and Jungst, S.B., 1981. Compensatory responses to feed restriction during the growing period. J. Anita. Sci., Abstr., 51: 14.
272 RESUME Campbell, R.G., Taverner, M.R. et Curic, D.M., 1983. Effets du niveau d'alimentation de 20 ~ 45 kg sur les performances et la composition de la carcasse de porcs ~lev~s jusqu'au poids vif de 90 kg. Livest. Prod. Sci., 10:265--272 (en anglais). Vingt-sept porcs femelles ont dt~ utilisds pour ~tudier les effets de trois niveaux d'alimentation (bas, m o y e n et ad libitum) entre 20 et 45 kg sur les performances de croissance et la composition de la carcasse ~ 90 kg de poids vif. Pendant la phase de 20 ~ 45 kg, l'~l~vation du niveau d'alimentation augmente la vitesse de croissance (P < 0,05), les graisses corporelles et les mesures d'adiposit~ de la carcasse (P < 0,05) mais r~duit la teneur en eau corporelle (P < 0,05). Apr~s 45 kg, les porcs ayant re~u auparavant le niveau d'alimentation le plus bas avaient une croissance plus rapide (P < 0,05) et un indice de consommation (FCR) plus faible (P < 0,05) que les porcs soumis aux deux autres traitements avant 45 kg, et ~taient plus maigres ~ 90 kg (P < 0,05) que ceux nourris ~ volont~ entre 20 et 45 kg. Sur toute la p~riode de l'~tude (20--90 kg), les animaux les plus rationn~s avant 45 kg avaient la croissance plus lente (P < 0,05) mais l'indice de consommation plus faible (P < 0,05) que ceux des deux autres lots. Les porcs soumis ~ une restriction alimentaire mod~r~e entre 20 et 45 kg avaient la m ~ m e vitesse de croissance entre 20 et 90 kg que ceux nourris ad libitum pendant cette p~riode, mais leur indice de consommation ~tait inf~rieur (P < 0,05).
KURZFASSUNG Campbell, R.G., Taverner, M.R. und Curic, D.M., 1983. Einfluss des Ffitterungsniveau im Mastabschnitt 20 bis 45 kg auf die Leistung und SchlachtkSrperzusammensetzung yon Schweinen -- gem~istet bis 90 kg Lebendgewicht. Livest. Prod. Sci., 10:265--272 (auf englisch). Ffir die Untersuchung der Auswirkungen von drei Ffitterungsniveaus (gering, m~issig und ad libitum) im Mastabschnitt von 20 bis 45 kg auf Wachstumsleistung und Schlachtk6rperzusammensetzung bis zu einem Lebendgewicht yon 90 kg wurden 27 weibliche Tiere herangezogen. Wurde das Ffitterungsniveau in der Lebendgewichtsphase 20 bis 45 kg erhSht, so stiegen die Wachstumsrate (P < 0,05) sowie die Masse ffirKSrper und Auflagefett (P < 0,05) aber das KSrperwasser reduzierte sich (P <~ 0,05). Nach Erreichen des Gewichtsabschnittes yon 45 kg, wuchsen Schweine, die vorher auf d e m niedrigen Niveau geffittert wurden, schneller (P <~ 0,05) und hatten eine giinstigere Futterverwertung als Schweine der anderen beiden Ffitterungsniveaus; darfiberhinaus waxen diese Schweine dann mit 90 kg magerer (P < 0,05) als die, die im Mastabschnitt 20--45 kg ad libitum geffittertwurden. Eine Gesamtanalyse (20--90 kg) ergab, dass die Schweine mit d e m geringen Ffitterungsniveau bis z u m 45 kg-Gewicht zwar eine geringere Wachstumsrate (P < 0,05) aber auch eine gfinstigere Futterverwertung hatten als die Tiere der beiden anderen Ffitterungsniveaus. Schweine des mittleren Ffitterungsniveaus zeigten fiber den Gewichtsabschnitt 20-90 kg ein ~ihnliches Wachstum, hatten aber eine gfinstigere Futterverwertung als die ad libitum geffitterten Tiere.