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Autoradiographic studies of wool growth rate in Wensleydale crossbred lambs: absence of a marked circadian rhythm

Published online by Cambridge University Press:  02 September 2010

G. C. Priestley  and
M. L. Ryder
G. C. Priestley
Affiliation:
University Department of Dermatology, Royal Infirmary, Edinburgh EH3 9YW
M. L. Ryder
Affiliation:
ARC Animal Breeding Research Organisation, West Mains Road, Edinburgh EH9 3JQ
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Abstract

The linear growth rate of wool on three sites on each of six Wenslcydale × Blackface lambs was measured by wool fibre autoradiography following 11 injections of 35S-cystine. The first injection was given at 09.00 h, so that alternate 36h intervals between injections represented predominantly day (09.00 to 21.00h) or night (21.00 to 09.00 h). The overall mean growth rates on shoulder, mid-side and breech were 0·83, 0·96 and 0·95 mm/day. Differences between day and night growth rates were very small (proportionally<0·05) and inconsistent in 16 of the 18 samples; although breech samples from two sheep showed up to 0·14 faster growth in daytime, a circadian rhythm of wool growth seems unlikely on this evidence. Both linear wool growth rate and food intake increased steadily throughout the experiment.

Mid-side wool growth rates in a second group of three crossbred longwool lambs averaged 0·79, 100 and 1·14 mm/day and were relatively stable over a period of several months.

Type
Research Article
Information
Animal Production , Volume 33 , Issue 3 , December 1981 , pp. 259 - 263
Copyright
Copyright © British Society of Animal Science 1981

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References

REFERENCES

Bullough, W. S. and Laurence, E. B. 1958. The mitotic activity of the follicle. In The Biology of Hair Growth (ed. Montagna, W. and Ellis, R. A.), pp. 171–187. Academic Press, New York.CrossRefGoogle Scholar
Burns, M. 1967. The Katsina wool project. II—Coat and skin data from ¾-Merino and Wensleydale crosses. Trop. Agric, Trin. 44: 253–274.Google Scholar
Comaish, S. 1969a. Autoradiographic studies of hair growth in various dermatoses: investigation of a possible circadian rhythm in human hair growth. Br. J. Derm. 81: 283–288.CrossRefGoogle ScholarPubMed
Comaish, S. 1969b. Autoradiographic studies of hair growth and rhythm in monilethrix. Br. J. Derm. 81: 433–447.CrossRefGoogle ScholarPubMed
Downes, A. M. and Lyne, A. G. 1961. Studies on the rate of wool growth using [35S]cystine. Aust. J. biol. Sci. 14: 120–130.CrossRefGoogle Scholar
Downes, A. M. and Sharry, L. F. 1971. Measurement of wool growth and its response to nutritional changes. Aust. J. biol. Sci. 24: 117–130.CrossRefGoogle ScholarPubMed
Downes, A. M. and Wallace, A. L. C. 1965. Local effects on wool growth of intradermal injections of hormones. In Biology of the Skin and Hair Growth (ed. Lyne, A. G. and Short, B. F.), pp. 679–703. Angus and Robertson, Sydney.Google Scholar
Fisher, L. B. 1968. The diurnal mitotic rhythm in the human epidermis. Br. J. Derm. 80: 75–80.CrossRefGoogle Scholar
Galpin, N. 1948. A study of wool growth. Part II. Mean fibre thickness, density of fibre population, the area of skin covered by fibre, and the mean fibre length. J. agric. Sci., Camb. 38: 303–313.CrossRefGoogle Scholar
Nedelchev, D. and Dragnev, H. 1976. [Periodic changes in skin and wool growth in sheep. 1. Diurnal and seasonal rhythm of proliferative processes in hair bulbs.] Zhivotnovodni Nauki 13 (7): 21–26.Google Scholar
Potten, C. S., Jessup, B. A. and Croxton, M. B. 1971. Incorporation of tritiated thymidine into the skin and hair follicles. II. Daily fluctuations in 3H-TdR and 3H-UR levels. Cell Tissue Kinet. 4: 413–421.Google Scholar
Priestley, G. C. 1964. The structure and activity of skin follicles in sheep, rats and other mammals. Ph.D. Thesis, Univ. Leeds.Google Scholar
Priestley, G. C. 1965. Wool and hair growth on autografts of sheepskin. Proc. R. Soc. Med. 58: 808–810.Google Scholar
Priestley, G. C. 1966. Rates and duration of hair growth in the albino rat. J. Anat. 100: 147–157.Google ScholarPubMed
Ryder, M. L. 1978. The fleece of Wiltshire × Wensleydale sheep. Anim. Prod. 26: 325–329.Google Scholar
Saitoh, M., Usljka, M. and Sakamoto, M. 1969. Rate of hair growth. In Advances in the Biology of Skin, Vol. 9 (ed. Montagna, W. and Dobson, R. L.), pp. 183–201. Academic Press, New York.Google Scholar
Wilson, Patricia A. and Short, B. F. 1979. Cell proliferation and cortical cell production in relation to wool growth. Aust. J. biol. Sci. 32: 317–327.CrossRefGoogle ScholarPubMed