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Responses of sheep to annual cycles in nutrition. 2. Effects of diet and endogenous growth hormone during replenishment

Published online by Cambridge University Press:  02 September 2010

N. R. Adams ,
M. R. Sanders ,
J. R. Briegel ,
D. W. Peter  and
R. D. G. Rigby
N. R. Adams
Affiliation:
CSIRO Division of Animal Production, PO Wembley, WA 6014, Australia
M. R. Sanders
Affiliation:
CSIRO Division of Animal Production, PO Wembley, WA 6014, Australia
J. R. Briegel
Affiliation:
CSIRO Division of Animal Production, PO Wembley, WA 6014, Australia
D. W. Peter
Affiliation:
CSIRO Division of Animal Production, PO Wembley, WA 6014, Australia
R. D. G. Rigby
Affiliation:
CSIRO Division of Animal Production, Blacktown, NSW 2148, Australia
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Abstract

The rôle of growth hormone (GH) in normal growth is well established, but its rôle during recovery after live-weight loss in adults is less defined. This study examined the interaction of endogenous GH with energy or protein supplements during re-feeding of ewes in low body condition. Control ewes and ewes immunized against growth hormone-releasing hormone were housed in individual pens and given food below maintenance for 107 days, before re-feeding was initiated by supplementing half of each group with either fish meal or barley for 28 days (P1), after which the supplements were switched for a further 28 days (P2). Following supplementation, the ewes grazed abundant green pasture for 92 days before slaughter. Immunization reduced plasma concentrations of GH, insulin, insulin-like growth factor 1 (IGF-1) and prolactin. Production responses to the two food supplements were similar in the control and immunized ewes, but when grazed at pasture immunized ewes gained live weight more slowly (P = 0·06), grew less wool (P<0·01), and had heavier fat depots, but lighter carcass, skin and liver weights at slaughter. The sequence of re-feeding treatments affected subsequent wool production in both control and immunized ewes. During P2, and for 52 days after supplementation ceased, ewes supplemented with fish meal then barley (F/B) produced less wool (P < 0·05) than those supplemented with barley followed by fish meal (B/F). At slaughter, the F/B ewes had lighter omental and kidney fat depots than the B/F ewes (P < 0·05). It is concluded that during live-weight regain, endogenous GH initially affected fat deposition, which in turn affected food intake and wool growth. Furthermore, provision of supplements with a high protein to energy ratio to sheep in low body condition, followed by supplements with a low protein to energy ratio, caused a prolonged suppression of wool growth. This effect was not mediated by endogenous GH.

Keywords

live weightnutritive ratiosheepsomatotropinwool
Type
Research Article
Information
Animal Science , Volume 62 , Issue 2 , April 1996 , pp. 287 - 292
Copyright
Copyright © British Society of Animal Science 1996

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References

REFERENCES

Adams, N. R., Briegel, J. R., Rigby, R. D. G., Sanders, M. R. and Hoskinson, R. M. 1996. Response of sheep to annual cycles in nutrition. 1. Rôle of endogenous growth hormone during under-nutrition. Animal Science 62: 279–286.CrossRefGoogle Scholar
Arnold, G. W., Charlick, A. J. and Eley, J. R. 1984. Effects of shearing time and time of lambing on wool growth and processing characteristics. Australian Journal of Experimental Agriculture and Animal Husbandry 24: 337–343.CrossRefGoogle Scholar
Bass, J. J., Hodgkinson, S. C., Brier, B. H., Carter, W. D. and Gluckman, P. D. 1992. Effects of bovine somatotrophin on insulin-like growth factor-1, insulin, growth and carcas composition of lambs. Livestock Production Science 3: 321–334.CrossRefGoogle Scholar
Costigan, P. and Ellis, K. J. 1987. Analysis of faec chromium derived from controlled release marker device New Zealand journal of Technology 3: 89–92.Google Scholar
Hara, A. and Radin, N. S. 1978. Lipid extraction of tissue with a low-toxicity solvent. Analytical Biochemistry 9??? 420–428.CrossRefGoogle Scholar
Johnsson, I. D., Hart, I. C. and Butler-Hogg, B. W. 1985 The effects of exogenous bovine growth hormone am bromocriptine on growth, body development, fleece weigh and plasma concentrations of growth hormone, insulin an prolactin in female lambs. Animal Production 41: 207–217.Google Scholar
MacRae, J. C., Bruce, L. A., Hovell, F. D. DeB., Hart, I. CInkster, J., Walker, A. and Atkinson, T. 1991. Influence c protein nutrition on the response of growing lambs texogenous bovine growth hormone. journal of Endocrinolog 130:53–61.CrossRefGoogle Scholar
MacRae, J. C. and Lobley, G. E. 1991. Physiological and metabolic implications of conventional and novel method for the manipulation of growth and production. Livestoc Production Science 27: 43–59.CrossRefGoogle Scholar
Purser, D. B. and Southey, I. N. 1984. Fluctuations ii nutrient supply in the south west of Western Australia. In Wool production in Western Australia (ed. Baker, S. K., Masters, D. G and Williams, I. H.), pp. 99–111. Australian Society of Animal Production, Perth, WA.Google Scholar
Reklewska, B. 1974. A note on the effect of bovin somatotrophic hormone on wool production in growing lambs. Animal Production 19: 253–255.Google Scholar
Rowe, J. B., Brown, G., Ralph, I. G., Ferguson, J. and Wallace, J. F. 1989. Supplementary feeding of young Merino sheep, grazing wheat stubble, with different amounts of lupin, oat or barley grain. Australian Journal of Experimental Agriculture 29: 29–35.CrossRefGoogle Scholar
Thompson, A. N. and Curtis, K. M. S. 1990. The effects of lupin or oat grain supplements on live weight change staple strength and position of break for sheep grazing dry annual pastures. Proceedings of the Australian Society for Animal Production 18: 400–403.Google Scholar