Effect of Lactation on Some Aspects of Reproduction in Progestagen-PMSG Treated Ewes during the Non-Breeding Season

The responses of lactating and dry ewes to progestagen-PMSG treatment during the non-breeding season and the survival of eggs transferred between dry and lactating ewes and vice versa were studied in two experiments. The incidence of oestrus and ovulation, ovulation rate and plasma progesterone conc...

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Bibliographic Details
Published in:Irish Journal of Agricultural and Food Research 1981-01, Vol.20 (1), p.1-8
Main Authors: Quirke, J. F., Hanrahan, J. P., Sheehan, W., Gosling, J. P.
Format: Article
Language:English
Subjects:
Contraceptive sponges
Eggs
Ewes
Fertilization
Lactation
Ova
Ovulation
Sheep
Sponges
Zygotes
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Summary:The responses of lactating and dry ewes to progestagen-PMSG treatment during the non-breeding season and the survival of eggs transferred between dry and lactating ewes and vice versa were studied in two experiments. The incidence of oestrus and ovulation, ovulation rate and plasma progesterone concentrations on days 11 and 12 after oestrus were similar in lactating and non-lactating ewes following the same progestagen-PMSG treatment. The percentage of eggs recovered which were fertilized was significantly higher in dry (64.9%) than in suckling ewes (34.2%). In addition, lactation adversely affected the establishment of pregnancy and egg survival; on day 100 after the transfer of fertilized eggs obtained from dry donor ewes, 80% of non-lactating recipient ewes were pregnant compared with 53% of suckling recipients. There was no evidence to indicate that the quality of fertilized eggs was poorer in lactating than in non-lactating ewes.
ISSN:0578-7483
0791-6833