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The effect of treatment with a gonadotrophin releasing hormone on the fertility of dairy cows

Published online by Cambridge University Press:  24 November 2017

S.B. Drew
Affiliation:
ADAS MAFFColey ParkReading RG1 6DT
A.R. Peters
Affiliation:
Hoechst UK LtdWalton ManorMilton KeynesMK7 7AJ
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Extract

Work in New Zealand has suggested that treatment of dairy cows with buserelin an analogue of GnRH between days 11 and 13 after insemination can increase pregnancy rate by reducing embryo loss (MacMillan, Taufa and Day, 1986). This effect is probably mediated via a luteoprotective mechanism (MacMillan, Thatcher & Drost 1989; Thatcher, MacMillan, Hansen & Drost, 1989). The present study was carried out to attempt to confirm this effect of buserelin under UK conditions.

A total of 660 Holstein/Friesian cows on 10 commercial dairy farms were used. The cows were paired according to date, of previous calving and allocated at random to control or treated group on the day of service. Only cows in the parity range 1-5 with no obvious reproductive disorders were used. Bulls and inseminators were used on the same number of cows in each group. Milk samples were taken on the day of service for progesterone assay. Cows not in oestrus were removed from the study. Cows in treated groups were given an intramuscular injection of 10 ug buserelin [2.5 ml Receptal, Hoechst] 12 days after first insemination. Cows not observed to return to oestrus before Day 24 were re-sampled for progesterone assay. Pregnancy was confirned by palpation or ultrasonic scanning at six weeks.

Type
Ruminant Endocrinology
Copyright
Copyright © The British Society of Animal Production 1991

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References

MacMillan, K.L., Taufa, V.K. and Day, (1986). Animal Reproduction Science 11, 110.Google Scholar
MacMillan, K.L., Thatcher, W.W. and Drost, M (1989). Proc. 49th Annual Conference of New Zealand Society of Animal Production, 115.Google Scholar
Tnatcher, W.W., MacMillan, K.L., Hansen, P.J. and Drost, M. (1989). Theriogenology 31, 149164.Google Scholar