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The effect of changes in dietary protein and energy on growth, body composition and mohair fibre characteristics of British Angora goats

Published online by Cambridge University Press:  02 September 2010

Md. Shahjalal ,
H. Galbraith  and
J. H. Topps
Md. Shahjalal
Affiliation:
School of Agriculture, 581 King Street, Aberdeen AB9 1UD
H. Galbraith
Affiliation:
School of Agriculture, 581 King Street, Aberdeen AB9 1UD
J. H. Topps
Affiliation:
School of Agriculture, 581 King Street, Aberdeen AB9 1UD
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Abstract

Twenty-four castrated male British Angora goats of Australasian origin aged 11 months and weighing 23·5 kg live weight were studied in a 112-day experiment. They were allocated in a 2 × 2 factorial design to receive diets containing, per kg dry matter, concentrations of estimated metabolizable energy (ME) of 10·2 M] (LE) or 11·9 MJ (HE) and crude protein concentrations of 108 g (LP) or 180 g (HP). The HE diets were offered to provide a dry-matter intake of 30 g/kg live weight and the LE diets to provide 0·85 of the ME intake of HE diets.

In comparison with LE diets, the HE diets, on average, increased live-weight gain, food conversion efficiency, carcass weight, killing-out proportion, empty body weight, cross-sectional area of m. longissimus dorsi and fat thickness over m. serratus dorsalis and weights in the carcass for dissected lean tissue, crude protein (N × 6·25) and dissected and chemically extracted fat. Weights of shoulder, hind barrel, and best-end joints and their weights of dissected lean and fat were increased on HE diets. No consistent effects due to dietary energy were observed for yield or diameter of mohair fibres.

The greater intake of dietary protein resulted, on average, in increased values for live-weight gain, efficiency of food conversion, carcass weight, weight of dissected carcass lean tissue and crude protein, killing-out proportion and cross-sectional area of m. longissimus dorsi. The greater intake of dietary protein increased significantly both yield and diameter of mohair fibre.

Significant interactions between protein and energy for empty body weight, carcass weight and carcass fat indicated that increasing dietary protein intake had a greater positive effect on the low than on the high energy diets. Similarly, increasing the dietary energy consumption on the LP diets produced a greater positive effect than that recorded on the HP diets.

The results indicated that growth and lean tissue deposition were affected by both protein and energy intakes but that mohair fibre characteristics were affected consistently only by protein nutrition.

Keywords

Angora goatscarcass compositionenergy intakemohairprotein intake
Type
Research Article
Information
Animal Production , Volume 54 , Issue 3 , June 1992 , pp. 405 - 412
Copyright
Copyright © British Society of Animal Science 1992

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References

Agricultural Research Council. 1984. The nutrient requirements for ruminant livestock. Suppl. no. 1 Commonwealth Agricultural Bureaux, Slough.Google Scholar
Ash, A. J. and Norton, B. W. 1984. The effect of protein and energy intake on cashmere and body growth of Australian Cashmere goats. Proceedings of the Australian Society Animal Production 15: 247–250.Google Scholar
Atkinson, T., Fowler, V. R., Garton, G. A. and Lough, A. K. 1972. A rapid method for the accurate determination of lipid in animal tissue. Analyst, London 97: 562–568.CrossRefGoogle Scholar
Black, J. L. and Reis, P. J. 1979. Speculation on the control of nutrient partition between wool growth and other body functions. In Physiological and environmental limitations wool growth (ed. Black, J. L. and Reis, P. J.), pp. 269–293. University of New England Publishing Unit, Armidale, Australia.Google Scholar
Brown, A. J. and Williams, D. R. 1987. Sheep carcass evaluation — measurement of composition using standardised butchery method. Memorandum, Meat Research Institute, Langford, Bristol, no. 38.Google Scholar
Calhoun, M. C., Lupton, C. J., Kuhlmann, S. W. and Baldwin, B. C. 1988. Dietary energy intake effects on mohair growth. Progress report, Texas Agricultural Station no. 4589.Google Scholar
Cooper, R. A., Kirk, J. A., Lerwill, D. and Draper, R. 1989. Effects of castration on the performance and carcass composition of intensively reared Saanen goats. Animal Production 48: 654 (abstr.).Google Scholar
Devendra, C. 1988. Nutrition and meat production. In Goat meat production in Asia (ed. Devendra, C.), Proceedings of workshop held in Tando Jam, Pakistan. Proceedings 268e, pp. 30–43.Google Scholar
Galbraith, H., McCulloch, T., Scaife, J. R. and Keeling, B. J. 1988. Effect of barley, sugar-beet pulp and protein level in the diet on growth, body composition and blood metabolites and insulin concentrations of entire male lambs. Animal Production 46: 514 (abstr.).Google Scholar
Gifford, D. R. 1989. A note on the variation in fleece characteristics over the body of Australian Angora bucks. Animal Production 48: 245–247.Google Scholar
Harris, P. M. and Lobley, G. E. 1991. Amino acid and energy metabolism in peripheral tissues of ruminants. In Physiological aspects of digestion and metabolism in ruminants (ed. Tusda, T., Sasaki, Y. and Kawashima, R.), pp. 201–230. Academic Press, London.CrossRefGoogle Scholar
Hemsley, J. A. and Reis, P. J. 1984. Amino acid and wool growth. In Ruminant physiology — concepts and consequences (ed. Bakey, S. K., Gawthorne, J. M., Mackintosh, J. B. and Purser, D. B.), pp. 253–261. University of Western Australia, Perth.Google Scholar
Hobson, V., Grobbelaar, P. D., Wentzel, D. and Koen, A. 1986. Effect of level of supplementary feeding on mohair production and reproductive performance of Angora ewes grazing Atriplex nummularia. South African Journal of Animal Science 16: (2), 95–96.Google Scholar
Huston, J. E. 1980. Supplemental energy and protein effects on growth-rate and mohair production in weaned Angora female kids. Progress report, Texas Agricultural Experiment Station, no. 3706.Google Scholar
Huston, J. E. and Shelton, M. 1967. The influence of level of protein on performance of billy kids fed in dry lot. Progress report, Texas Agricultural Experiment Station, no. 2454.Google Scholar
Huston, J. E., Shelton, M. and Ellis, W. C. 1971. Nutritional requirements of the Angora goats. Texas Agricultural Experiment Station B 1105.Google Scholar
Hynd, P. I. 1989. Effects of nutrition on wool follicle cell kinetics in sheep differing in efficiency of wool production. Australian Journal of Agricultural Research. 40: 409–417.CrossRefGoogle Scholar
Lawes Agricultural Trust. 1987. GENSTAT V, mark 4.03. Rothamsted Experimental Station, Harpenden, Hertfordshire.Google Scholar
McGregor, B. A. 1984. Growth, development and carcass composition of goats: a review. In Goat production and research in the tropics (ed. Copland, J. W.), Proceedings of workshop, University of Queensland, Brisbane. Australian Centre for International Agricultural Research, proceeding 7, pp. 82–90.Google Scholar
National Research Council. 1981. Nutrient requirements of domestic animals, no. 15. Nutrient requirements of goats: dairy and meat goats in temperate and tropical countries. National Academy Press, Washington, DC.Google Scholar
Ryder, M. L. 1973. Hair. Institute of Biology, studies in biology no. 41. Edward Arnold, London.Google Scholar
Shelton, M. and Huston, J. E. 1966. Influence of level of protein and other factors on the performance of yearling billies fed in dry lot. Progress report, Texas Agricultural Experiment Station, no. 2399.Google Scholar
Sinclair, L. A., Galbraith, H. and Scaife, J. R. 1991. Effect of dietary protein concentration and cimaterol on growth and body composition of entire male lambs. Animal Feed Science and Technology 34: 181–192.CrossRefGoogle Scholar
Thonney, M. L., Taylor, St C. S., Murray, J. I. and McClelland, T. H. 1987. Breed and sex differences in equally mature sheep and goats. 2. Body components at slaughter. Animal Production 45: 261–276.Google Scholar