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Ovulation rate in ewes treated with pregnant mares' serum gonadotrophin and luteinizing hormone releasing factor

Published online by Cambridge University Press:  27 March 2009

P. T. McGovern
Affiliation:
Departments of Anatomy and Animal Husbandry, Boltons Park, Potters Bar, Hertfordshire
J. A. Laing
Affiliation:
Departments of Anatomy and Animal Husbandry, Boltons Park, Potters Bar, Hertfordshire

Extract

Although the administration of pregnant mares' serum gonadotrophin (PMSG) to induce superovulation is a well established procedure (see Anderson, Schultz & Melampny, 1963), the unpredictability of the response to this treatment continues to impose a constraint on the commercial application of egg transfer techniques in the large domestic animals. In sheep, the additional use of human chorionic gonadotrophin (HCG) has been mainly centred on attempts to control the time of ovulation (Ortavant, Thibault & Wintenberger, 1949; Braden, Lamond & Radford, 1960; Dziuk et al. 1964; McGovern, Williams & Hancock, 1969). However, Killeen & Moore (1970) found that the proportion of follicles which rupture was increased in PMSG-treated ewes which had been given HCG at the beginning of oestrus. The purpose of the observations recorded here was to examine the possibility that a further gain in ovulation rate in PMSG-treated sheep might be obtained with the use of luteinizing hormone releasing factor (LHRF). No attempt was made to reproduce physiological levels of the releasing factor and dosage was aimed at achieving a superovulatory effect.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1976

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References

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