This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by PELLETIER, J. Articles by THIMONIER, J. Search for Related Content PubMed Articles by PELLETIER, J. Articles by THIMONIER, J.

COMPARISON OF THE INDUCED PREOVULATORY LH DISCHARGE IN LACTATING AND DRY SHEEP DURING SEASONAL ANOESTRUS

During seasonal anoestrus in Île-de-France sheep, progestagen treatment with vaginal sponges associated with an intramuscular injection of PMSG induces oestrus and ovulation in dry and lactating females (42 days post partum).

The fertility after artificial insemination, expressed as the percentage of treated ewes which subsequently lamb, is lower in lactating ewes at the induced oestrus than in the non-lactating ewes (35% versus 70%, Colas, Brice, Courot & Cottier, 1971).

The present experiment was designed to investigate the effect of lactation on the induced preovulatory LH discharge since it may have an effect on fertility.

In April, during the period of seasonal anoestrus, twelve non-lactating ewes (Groups 1 and 2) and twelve lactating ewes (Groups 3 and 4) were submitted to the various treatments shown in Table 1. The conditions of treatment for animals in Groups 1