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Growth rate and its effect on empty body weight, carcass weight and dissected carcass composition of sheep

Published online by Cambridge University Press:  27 March 2009

D. M. Murray
Affiliation:
School of Wool and Pastoral Sciences, University of New South Wales, Kensington, New South Wales, Australia
Olga Slezacek
Affiliation:
Hawkesbury Agricultural College, Richmond, New South Wales, Australia

Summary

The effect of three different growth rates from 15 to 40 kg live weight on the body composition of lambs was studied. The treatments were: High (H) ad-libitum feed intake, Low (L) restricted feed intake and High–Maintenance–High (HMH) ad-libitum feed intake from 15 to 25 kg followed by a 50-day period during which live weight was maintained constant, which in turn was followed by ad-libitum feeding. The animals were individually penned and fed a pelleted lucerne chaff-cereal grain mixture. Two animals were killed at the start of the experiment (15 kg) and the remaining 27 animals (nine in each treatment) were killed at common live weights of 25, 30, 35 and 40 kg. Analyses of covariance were used to compare linear regression equations representing results from each treatment using the logarithmic transformation of the allometric equation, y = axb.

Animals in the H and L treatments had a mean growth rate from 15 kg until slaughter of 0·23 and 0·09 kg/day, respectively. From a live weight of 15 to 25 kg, the HMH group grew at a similar rate as the H group, viz. 0·22 and 0·21 kg/day, respectively. After the 50-day period of maintenance of live weight, the HMH animals killed at 30, 35 and 40 kg showed a marked compensatory growth response to ad-libitum feeding. These HMH animals had a mean growth rate of 0·37 kg/day compared with 0·26 kg/day for H animals over identical live-weight ranges.

Empty body weight (EBW) formed a similar proportion of full body weight (FBW) in all three treatments. As a proportion of FBW, hot carcass weight (HCW) was similar in the H and L treatments, while at the 35 and 40 kg slaughter weights HCW was less in the HMH than in the H treatment. HCW also formed a lower proportion of EBW at the 35 and 40 kg slaughter weights in the HMH, than in both the H and L treatments. In the L treatment, HCW formed a greater proportion of EBW than in the H treatment, indicating a greater offal component of EBW in the H animals.

The results of carcass dissection studies showed that, at the same dissected side weight (DSW), the amount of muscle, bone, connective tissue and total side fat (TSF) was similar in the three treatments. Although no differences were found between treatments in TSF, there were significant treatment effects on both the subcutaneous and inter-muscular fat depots. Animals in the H treatment had more and less, respectively, subcutaneous and intermuscular fat than the L animals. The amount of intermuscular fat was also greater in the HMH than in the H treatment.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1976

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References

Black, J. L. (1974). Manipulation of body composition through nutrition. Proceedings of the Australian Society of Animal Production 10, 211–18.Google Scholar
Butterfield, R. M. (1963). Estimation of carcass composition; the anatomical approach. In Symposium on Carcase Composition and Appraisal of Meat Animals (ed. Tribe, D. E.), 4.1 to 4.13. Melbourne, Australia: C.S.I.R.O.Google Scholar
Butterfield, R. M. (1966). The effect of nutritional stress and recovery on the body composition of cattle. Research in Veterinary Science 7, 168–79.CrossRefGoogle ScholarPubMed
Little, D. A. & Sandland, R. L. (1975). Studies on the distribution of the body fat in sheep during continuous growth, and following nutritional restriction and rehabilitation. Australian Journal of Agricultural Research 26, 363–74.CrossRefGoogle Scholar
Lohse, C. L., Pryor, W. J. & Butterfield, R. M. (1973). The use of growth patterns of muscle measurements, chemical data, energy, and muscle weights to differentiate between normal and recovering muscle. Australian Journal of Agricultural Research 24, 279–85.CrossRefGoogle Scholar
McManus, W. R., Reid, J. T. & Donaldson, L. E. (1972). Studies of compensatory growth in sheep. Journal of Agricultural Science, Cambridge 79, 112.CrossRefGoogle Scholar
Meyer, J. H. & Clawson, W. J. (1964). Undernutrition and subsequent rehabilitation in rats and sheep. Journal of Animal Science 23, 214–24.CrossRefGoogle Scholar
Morgan, J. A. & Owen, J. B. (1972). The nutrition of artificially reared lambs. 1. The effect of different feeding methods applied at three stages of growth. Animal Production 15, 285–92.Google Scholar
Morgan, J. A. & Owen, J. B. (1973). The nutrition of artificially reared lambs. 3. Tho effect of sex on the performance and carcass composition of lambs subjected to different nutritional treatments. Animal Production 16, 4957.Google Scholar
Murray, D. M. & Slezacek, Olga (1975). The effect of growth rate on muscle distribution in sheep. Journal of Agricultural Science, Cambridge 85, 189–91.CrossRefGoogle Scholar
Murray, D. M., Tulloh, N. M. & Winter, W. H. (1974). Effects of three different growth rates on empty body weight, carcass weight and dissected carcass composition of cattle. Journal of Agricultural Science, Cambridge 82, 535–48.CrossRefGoogle Scholar
O'Donovan, W. M. (1974). Developmental changes in the bodies of Dorper sheep. 4. Effects of rate of live body mass gain and energy concentration of diet on body composition of weaned Dorper lambs. Rhodesian Journal of Agricultural Research 12, 113–25.Google Scholar
Russel, A. J. F., Doney, J. M. & Gunn, R. G. (1971). The distribution of chemical fat in the bodies of Scottish Blackface ewes. Animal Production 13, 503–9.Google Scholar
Russel, A. J. F., Gunn, R. G. & Doney, J. M. (1968). Components of weight loss in pregnant hill ewes during winter. Animal Production 10, 4351.CrossRefGoogle Scholar
Seebeck, R. M. & Tulloh, N. M. (1968). Developmental growth and body weight loss of cattle. III. Dissected components of the commercially dressed carcass, following anatomical boundaries. Australian Journal of Agricultural Research 19, 673–88.CrossRefGoogle Scholar
Winter, W. H. (1971). A study of weight loss and compensatory gain in sheep. Ph.D. Thesis, University of Melbourne.Google Scholar