PROTOCOLS OF ESTRUS INDUCTION AND SYNCHRONIZATION IN EWE

Abstract

The objective of this study was to evaluate the effects of progestagen treatment of different duration, PGF₂a and ram effect on estrus induction synchronization in ewes. In Experiment I, ewes (n=48) received vaginal sponges with MAP (medroxyprogesterone) for nine or 14 days (G-9 and G-14, respectively), followed by PGF₂a treatment and estrus detection. There were no differences in estrus (69.6 and 80%), conception (50 and 55%), and pregnancy rates (34.8 e 44.0%) between G-9 and G-14, respectively. In Experiment II, ewes (n=151) were divided into three groups: G-6 received vaginal sponges with MAP for 6 days, followed by PGF₂a treatment and estrus detection, G-PGF received only PGF₂a treatment, and G-RF were only exposed to males after a period of separation. Estrus rates were greater (p<0.05) in G-6 and G-PGF groups (58 and 39%, respectively) than in G-EF group (11%). In conclusion, it was possible to reduce the duration of progestagen treatment; however, the use of PGF₂a during the breeding season transition without progestagen seemed to reduce estrus rates. KEYWORDS: MAP; PGF₂a; ram effect; Suffolk.