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The effects of short-term undernutrition and adrenocortical stimulation on wool growth

Published online by Cambridge University Press:  02 September 2010

C. J. Thwaites
C. J. Thwaites
Affiliation:
Department of Livestock Production, University of New England, Armidale, New South Wales, 2351
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Summary

Seven daily doses of 60 or 120 mg cortisol administered to mature sheep given a maintenance ration depressed wool fibre diameter by approximately 10%. Similar treatment with 120 mg cortisol for 14 days produced a more severe and prolonged effect, though fibre diameter was unaffected by a series of seven injections of 40 IU ACTH given every second day.

Fourteen days at 10% of maintenance and 14 days' cortisol treatment were applied to mature sheep fed either continually at 150% maintenance, or at 75% followed by 150% maintenance. Cortisol treatment was associated with a significant reduction in fibre diameter only in the animals fed at 150% maintenance. Restriction to 10% maintenance for 14 days had no such effect. Approximately 20% of fibres were shed following cortisol treatment in both nutritional groups, but a marked ‘break’ in the fleece occurred only in the 75% maintenance group.

A low plane of nutrition is confirmed as a major factor predisposing to ‘tenderness’ and ‘break’, and short-term adrenocortical stimulation is shown to be sufficient to produce the reduction in fibre diameter and increased fibre shedding associated with these faults. However, semi-starvation (represented by restriction to 10% of maintenance) appears to have played a relatively minor role in their development.

Type
Research Article
Information
Animal Production , Volume 15 , Issue 1 , August 1972 , pp. 39 - 46
Copyright
Copyright © British Society of Animal Science 1972

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References

REFERENCES

Barnard, A. 1962. The Simple Fleece. Melbourne University Press.Google Scholar
Bassett, J. M. 1963. The influence of cortisol on feed intake and glucose metabolism in sheep. J. Endocr. 26: 539–553.CrossRefGoogle ScholarPubMed
Chapman, R. E. and Wheeler, J. L. 1963. Dye-banding: a technique for fleece growth studies. Aust. J. Sci. 26: 53–54.Google Scholar
Doney, J. M. and Smith, W. F. 1969. Casting of the fleece in sheep. Estimation of experimentally induced fibre shedding rate. J. agric. Sci., Camb. 73: 231–237.CrossRefGoogle Scholar
Ferguson, K. A., Wallace, A. L. C. and Lindner, H. R. 1965. Hormonal regulation of wool growth. In Biology of the Skin and Hair Growth (ed. Lyne, A. G. and Short, B. F.), Chap. 41. Angus and Robertson, Sydney.Google Scholar
Kilgour, R. and De Langen, H. 1970. Stress in sheep resulting from management practices. Proc. N.Z. Soc. Anim. Prod. 30: 65–76.Google Scholar
Lindner, H. R. and Ferguson, K. A. 1956. Influence of the adrenal cortex on wool growth and its relation to ‘break’ and ‘tenderness’ of the fleece. Nature, Lond. 177: 188–189.CrossRefGoogle Scholar
Reid, R. L. and Mills, S. C. 1962. Studies on the carbohydrate metabolism of sheep. XIV. The adrenal response to psychological stress. Aust. J. agric. Res. 13: 282–295.CrossRefGoogle Scholar
Roberts, N. F., James, J. F. P. and Burgmann, V. D. 1960. Tenderness in fleece wool. J. Text. Inst. 51: 935–948.CrossRefGoogle Scholar
Ryder, M. L. 1956. Observations on nutritional and seasonal changes in the fleeces of some Masham sheep. J. agric. Sci., Camb. 47: 129–144.Google Scholar