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Effect of mating management and PMSG dose on lambing outcome in ewes bred in late anoestrus

Published online by Cambridge University Press:  27 March 2009

M. P. Boland ,
T. F. Crosby  and
I. Gordon
M. P. Boland
Affiliation:
Department of Agriculture, University College, Lyons Estate, Newcastle, Co. Dublin, Eire
T. F. Crosby
Affiliation:
Department of Agriculture, University College, Lyons Estate, Newcastle, Co. Dublin, Eire
I. Gordon
Affiliation:
Department of Agriculture, University College, Lyons Estate, Newcastle, Co. Dublin, Eire
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Summary

Oestrus and ovulation was controlled by progestagen-impregnated sponges in 279 adult dry ewes in late anoestrus: at pessary withdrawal, ewes received doses of 0, 250, 500 or 750 i.u. pregnant mare serum gonadotrophin (PMSG). Rams were introduced to half the number of ewes which did not receive PMSG at the time of sponge withdrawal and to the remainder 48 h later. A significantly lower (P < 0·05) oestrous response was observed in ewes which did not receive PMSG but were introduced to rams at 48 h, when compared with ewes introduced to rams at time of sponge withdrawal. With iams introduced at 48 h a greater precision of synchronization was achieved by the use of PMSG (P < 0·05). Differences in conception rates were not evident between the various treatment groups, but a significantly higher (P < 0·05) litter size followed the use of the 750 i.u. PMSG dose.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 97 , Issue 2 , October 1981 , pp. 445 - 447
Copyright
Copyright © Cambridge University Press 1981

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