Factors Affecting the Postpartum Onset of Estrus in Local Ewes

Abstract

The delayed onset of estrus following lambing reduces the productivity of sheep. The present study was carried out to determine the key factors affecting the early onset of postpartum estrus in local ewes of Bangladesh. The effects of body weight, breed, season, presence of male following delivery and suckling on the postpartum onset of estrus were observed. Seventeen ewes (12 Indigenous and 7 Garole) were used in this study. The pregnancy and delivery were monitored. The indigenous ewes with higher body weight (14.87±0.27 kg) showed earlier postpartum onset of estrus (28.8±5.48 vs. 46±8.96 days) compared to lower body weight (12.89±0.48 kg). Similarly, the earlier postpartum onset of estrus (28.5±8.5 vs. 37±9.0 days) was observed in Garole ewes of higher body weight compared to lower body weight (28.3±2.65kg vs. 24.42±0.22kg). No significant difference was observed on Days of postpartum estrus onset between the breed, although Garole breed having higher body weight exhibited estrus earlier. The postpartum onset of estrus was earlier (27±7.56 vs. 44.57±7.47 days) during breeding season compared to non-breeding season in indigenous ewes. Indigenous ewes showed significantly (P<0.05) earlier onset of estrus (21.5±0.5 vs. 41.88±6.6 days) in the presence of ram compared to the absence. Similarly, an earlier onset of estrus was observed in Garole ewes, however the difference was insignificant. The postpartum onset of estrus was significantly (P<0.01) delayed (49.85±5.18 vs. 17.75±2.3 days) in the indigenous ewes of suckling group compared to the non-suckling group. A similar trend was observed in Garole ewes (37±9.0 vs. 28.5±8.5 days); however, the difference was not significant. Therefore, the economic losses due to delayed postpartum estrus could be prevented through the management of above-mentioned factors.