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Possible causes of differences in glucose metabolism between Angora goats of two different phenotypes

Published online by Cambridge University Press:  02 September 2010

P. B. Cronjé
P. B. Cronjé
Affiliation:
Irene Animal Production Institute, Irene, South Africa
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Abstract

Previous results have shown that certain phenotypes of Angora goat differ in respect of glucose metabolism and it has been proposed that this is linked to the high incidence of abortions in this breed. The aim of this experiment was to investigate adrenal function, food digestion and nutrient partitioning as possible causes of differences in glucose metabolism between a phenotype which produces a relatively large amount of mohair of a large fibre diameter (high producers) and a phenotype which produces less mohair of a smaller fibre diameter (low producers). Two groups consisting of 15 3-year-old Angora bucks each and representing two different phenotypes were given a maintenance diet for the duration of the trial. Plasma glucose concentrations during a 4-day fast were lower (P < 0·01) in high producers than in low producers and plasma glucose concentrations following insulin injection also fell to a greater extent in high producers than in low producers (P < 0·05), indicating that high producers were less able to mantain plasma glucose concentrations during periods of increased demand than low producers. The decrease in glucose concentration following insulin injection was accompanied by a rise in plasma cortisol concentrations until 60 min after the insulin injection but there were no differences between phenotypes (P > 0·05). Similarly, cortisol concentrations rose to a peak 60 min after ACTH injection and there were no differences between phenotypes (P > 0·05). In both instances, the pattern of cortisol concentrations was consistent with normal adrenal function and there were no indications of adrenal insufficiency. Although differences in digestion were observed between phenotypes (P < 0·01), these were small. There were no differences in nitrogen (N) intake or retention (P > 0·05). High producers deposited substantially more (proportionately 0·56) N as fleece than low producers (P < 0·01), and partitioned a greater proportion of N intake to fleece production (P < 0·01). It was concluded that adrenal insufficiency was not implicated in the observed differences in glucose metabolism between phenotypes but differences in digestibility and nutrient partitioning may play a role.

Keywords

Angoraglucosegoatsmetabolismphenotypes
Type
Research Article
Information
Animal Science , Volume 66 , Issue 3 , June 1998 , pp. 705 - 711
Copyright
Copyright © British Society of Animal Science 1998

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References

Association of Official Analytical Chemists. 1984. Official methods of analysis, 14th edition. Association of Official Analytical Chemists, Arlington, Virginia.Google Scholar
Bergman, E. N. 1973. Glucose metabolism in ruminants as related to hypoglycemia and ketosis. Cornell Veterinarian 63: 341–382.Google Scholar
Biddle, G. N., Evans, J. L. and Trout, J. R. 1975. Labile nitrogen reserves and plasma nitrogen fractions in growing cattle. Journal of Nutrition 105: 1584–1591.CrossRefGoogle ScholarPubMed
Bouchat, J. C. I., Doizé, F. and Paquay, R. 1980. Effects of fasting on blood composition and nitrogen losses in the adult sheep depending on previous diet and body weight. Reproduction, Nutrition, Development 20: 77–92.CrossRefGoogle Scholar
Caraway, W. T. 1982. Carbohydrates. In Fundamentals of clinical chemistry (ed. Teitz, W.), pp. 234–263. W. B. Saunders Co., Philadelphia.Google Scholar
Coleman, S. W. and Frahm, R. R. 1987. Nitrogen metabolism in crossbred steers with varying levels of Brahman using a nitrogen depletion-repletion regimen. Journal of Animal Science 65: 1077–1093.CrossRefGoogle ScholarPubMed
Cronje, P. B. 1992. Glucose metabolism and adrenal function in goats bred for fibre production (Angora goat) or meat production (Boer goat). South African Journal of Animal Science 22: 149–153.Google Scholar
Cronje, P. B. 1995. Differences in glucose response to insulin stimulation and fasting between Angora goats of two different phenotypes. Small Ruminant Research 16: 121–127.CrossRefGoogle Scholar
Cronje, P. B. and Smuts, M. 1994. Nutrient partitioning in Merino rams with different wool growth rates. Animal Production 59: 55–60.Google Scholar
Frandsen, J. C. 1987. Parasites as stressors: plasma cortisol responses of goats infected with the stomach worm Haemonchus contortus to exogenous corticotropin (ACTH). Veterinary Parasitology 23: 43–49.CrossRefGoogle ScholarPubMed
Gallagher, J. R. and Shelton, M. 1972. Efficiencies of conversion of feed to fiber of Angora goats and Rambouillet sheep. Journal of Animal Science 34: 319–321.CrossRefGoogle Scholar
Genstat 5 Committee. 1987. Genstat 5 reference manual. Clarendon Press, Oxford.Google Scholar
Graham, N. McC. and Searle, T. W. 1982. Energy and nitrogen utilization for body growth in young sheep from two breeds with differing capacities for wool growth. Australian Journal of Agricultural Research 33: 607–615.CrossRefGoogle Scholar
Kaneko, J. J. 1989. Clinical biochemistry of domestic animals (ed. Kaneko, J. J.). Academic Press, London.Google Scholar
Matras, J. and Preston, R. L. 1989. The role of glucose infusion on the metabolism of nitrogen in ruminants. Journal of Animal Science 67: 1642–1647.CrossRefGoogle Scholar
National Research Council. 1981. Nutrient requirements of domestic animals, no. 15: nutrient requirements of goats. National Academy of Sciences, Washington, DC.Google Scholar
Paquay, R., De Baere, R. and Lousse, A. 1972. The capacity of the mature cow to loose and recover nitrogen and the significance of protein reserves. British Journal of Nutrition 27: 27–37.CrossRefGoogle Scholar
Rijnberk, A. and Mol, J. A. 1989. Adrenocortical function. In Clinical biochemistry of domestic animals (ed. Kaneko, J. J.), pp. 610–628. Academic Press, London.Google Scholar
Shelton, M. and Terrill, V. 1989. Freeze loss survey results. Technical report no. 89–3, Texas Agricultural Experiment Station, College Station, Texas.Google Scholar
Smuts, M., Meissner, H. H. and Cronje, P. B. 1995. Retention time of digesta in the rumen: its repeatability and relationship with wool production of Merino rams. Journal of Animal Science 73: 206–210.CrossRefGoogle ScholarPubMed
Van der Westhuysen, J. M. and Roelofse, C. S. M. B. 1971. Effect of shelter and different levels of dietary energy and protein on reproductive performance in Angora goats with special reference to the habitual aborter. Agroanimalia 3: 129–132.Google Scholar
Van der Westhuysen, J. M. and Wentzel, D. 1971. Progress through selection against the aborting Angora goat. South African Journal of Animal Science 1: 101–102.Google Scholar
Van Rensburg, S. J. 1971. Reproductive physiology and endocrinology of normal and habitually aborting Angora goats. Onderstepoort Journal of Veterinary Research 38: 1–62.Google ScholarPubMed
Wade, L. and Sasser, L. B. 1970. Body water, plasma volume and erythrocyte volume in sheep. American Journal of Veterinary Research 31: 1375–1378.Google ScholarPubMed
Wentzel, D., Le Roux, M. and Botha, L. J. J. 1976. Effect of the level of nutrition on blood glucose concentration and reproductive performance of pregnant Angora goats. Agroanimalia 8: 59–62.Google Scholar
Zilva, J. F. and Pannall, P. R. 1984. Adrenal cortex: ACTH. In Clinical chemistry in diagnosis and treatment, pp. 139–155. Lloyd-Luke Ltd, London.Google Scholar