Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-08T12:24:53.175Z Has data issue: false hasContentIssue false
  • English
  • Français

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
Get access

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

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Asdell, S. A. 1946. Patterns of Mammalian Reproduction. Cornell University Press, Ithaca, N.Y.Google Scholar
Fisher, R. A. 1970. Statistical Methods for Research Workers. 14th ed. Oliver and Boyd, Edinburgh.Google Scholar
Gordon, I. 1971. Control of reproduction in sheep; towards programmed lambing. J. Dep. Agric. Repub. Ire. 38: 3–51.Google Scholar
Granger, W. 1947. Conception in lactating ewes. Aust. vet. J. 23: 143–145.CrossRefGoogle Scholar
Hafez, E. S. E. 1952. Studies on the breeding season and reproduction of the ewe. J. agric. Sci., Camb. 42: 189–265.CrossRefGoogle Scholar
Large, R. V. 1970. The biological efficiency of meat production from sheep. Anim. Prod. 12: 393–401.Google Scholar
Marshall, F. H. A. 1936. The Cruvian Lecture, XL Sexual periodicity and the causes which determine it. Phil. Trans. R. Soc. Ser. B 226: 423–456.Google Scholar
Mauleon, P. and Dauzier, L. 1965. [Variations in the duration of lactation anoestrus in ewes of the Ile-de-France breed.] Annls Biol. anim. Biochim. Biophys. 5: 131–143.CrossRefGoogle Scholar
Newton, J. E. and Betts, J. E. 1972. A comparison between the effect of various photoperiods on the reproductive performance of Scottish Half-bred ewes. J. agric. Sci., Camb. 78: 425–433.CrossRefGoogle Scholar
Owen, J. B. 1969. The intensification of sheep production. Outl. Agric. 6: 36–40.CrossRefGoogle Scholar
Restall, B. J. 1971. The effect of lamb removal on reproductive activity in Dorset × Merino ewes after lambing. J. Reprod. Fert. 24: 145–146.CrossRefGoogle ScholarPubMed
Roux, L. L. 1936. Sex physiology of sheep. Onderstepoort J. vet. Sci. Anim. Ind. 6: 465–717.Google Scholar
Williams, H. Ll. 1967. The intensification of sheep production. Ph.D. Thesis, Univ. London.Google Scholar
Yeates, N. T. M. 1949. The breeding season of sheep, with particular reference to its modification by artificial means using light. J. agric. Sci., Camb. 39: 1–43.CrossRefGoogle Scholar