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Superovulation in the ewe: the effects of source of gonadotrophin, season, breed and age

Published online by Cambridge University Press:  24 November 2017

K. Fernie ,
W.S. Dingwall ,
W.A.C. McKelvey  and
J. FitzSimons
K. Fernie
Affiliation:
Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh, EH9 3JG
W.S. Dingwall
Affiliation:
Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh, EH9 3JG
W.A.C. McKelvey
Affiliation:
Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh, EH9 3JG
J. FitzSimons
Affiliation:
Scottish Agricultural College, Kings Buildings, West Mains Road, Edinburgh, EH9 3JG
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Extract

The potential rate of genetic improvement which can be achieved in sheep through the use of multiple ovulation and embryo transfer (MOET) is limited by the great variation in the response of ewes to superovulation treatments. Factors which have been shown to influence natural ovulation rate in the ewe include season, breed, age and the administration of exogenous gonadotrophins from different sources. The following study was conducted to examine the effects of these factors on the response of ewes to superovulation treatments, with a view to increasing the mean ovulation rate and to concurrently decrease the between-ewe variability.

During the course of 4 experiments a total of 170 ewes (Suffolk and Texel) were treated with 45mg progestagen-impregnated intravaginal pessaries (Chronogest: Intervet Laboratories Ltd.) for a period of 12 days. Sixteen ewes had no further treatment and were used as controls. The remaining 154 ewes, were treated with one of two exogenous gonadotropin preparations on days 10, 11, 12 and 13 of the progestagen treatment period (day 0 = pessary insertion). One group (n = 76) was treated with a porcine pituitary extract (pFSH) and the second (n = 78) with a highly purified ovine FSH (Ovagen: Immuno-Chemical Products).

Type
Ruminant Reproduction
Information
Proceedings of the British Society of Animal Production (1972) , Volume 1993: Winter meeting , March 1993 , pp. 59
Copyright
Copyright © The British Society of Animal Production 1993

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References

Cahill, L.P. (1984) Folliculogenesis and ovulation rate in sheep. In “Reproduction in Sheep” (Eds. Lindsay, D.R. and Pearce, D.T.. Cambridge University Press, Sidney) pp.92–98 Google Scholar
Dingwall, W.S., McKelvey, W.A.C., Mylne, J. and Simm, G. (1993) An evaluation of MOET in Suffolk sheep. B.S.A.P. Winter Meeting 1993 Paper no. 103.CrossRefGoogle Scholar
Scaramuzzi, R.J., and Radford, H.M. (1983) Factors regulating ovulation rate in the ewe. J. Reprod. Fert. 69, 353–367.Google Scholar