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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

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