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Factors affecting the cessation of oestrous activity in ewes

Published online by Cambridge University Press:  02 September 2010

A. W. Speedy  and
J. B. Owen
A. W. Speedy
Affiliation:
Department of Applied Biology, University of Cambridge, Downing Street, Cambridge CB2 3DX
J. B. Owen
Affiliation:
Department of Applied Biology, University of Cambridge, Downing Street, Cambridge CB2 3DX
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Summary

In the first experiment, 10 ewes (¼ Finnish Landrace: ¾ Clun Forest) were maintained under natural daylength conditions and 10 were exposed to a constant daylength of 8 hr from 22 December until 1 June. No difference was demonstrated between treatments in dates of cessation of oestrous activity. It was concluded that oestrous activity will eventually cease, whether or not daylength increases after the shortest day.

In the second experiment, 40 similar ewes were mated at first oestrus of the natural breeding season (mean 7 September) and lambed in January. Twenty ewes suckled lambs and 20 had lambs removed within 24 hr of birth. No sucked ewes showed oestrus before the end of the breeding season, but 9 non-sucked ewes showed oestrus at a mean interval of 37·5 days after lambing and 4 of these subsequently lambed. Suckling appeared to inhibit oestrous activity and conception in ewes at this time of year.

Type
Research Article
Information
Animal Production , Volume 21 , Issue 3 , December 1975 , pp. 251 - 255
Copyright
Copyright © British Society of Animal Science 1975

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References

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