Effects of active immunization against androstenedione on the reproductive performance of Merino ewes (Short communication)

Author: J.P.C. Greyling
Year: 1989
Issue: 2
Volume: 19
Page: 96 - 97

The effect of active immunization against the ovarian steroid, androstenedione, on the reproductive performance of Merino ewes was investigated. Although a significant (P<0,01) increase of 19% in fecundity and 20,3% in lambing rate was obtained by treatment, the eventual number of lambs weaned as a percentage of the number of ewes lambed did not differ significantly from the control group, implying greater (P<0,01) lamb mortalities in ewes that were immunized. The practical application of immunization against ovarian steroids to improve reproductive efficiency in sheep requires further investigation and at this stage it would seem that survival of the lambs is the issue to address.


Keywords: androstenedione, Merino ewes, reproductive performance, steroid immunization
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