Effect of prostaglandin on estrus response and conception rate in lactating ongole cows

Aim: The present research work was carried to study the estrus response and conception rate in lactating Ongole cows consequence to double injection of prostaglandin. Material and Methods: Estrus synchronization was performed by double injection of PGF2α (Lutalyse, 5ml/cow) in purposively selected 22 lactating Ongole cows. The 1st injection was administered on 60 days post partum (day 0) followed nd by 2 injection on 72 days postpartum (day 12) and then insemination was carried out at observed estrus. Results: The ovarian response by ultrasound scanning revealed a dominant follicle of 10.00 + 0.78 mm 3-4 days after the PGF2α administration. Out of 22 cows treated with double injections of prostaglandins 18 cows exhibited estrus within 68.66 + 10.24 hrs. The duration of estrus and mean estrous cycle length recorded as 14.20+2.56 hrs and 21.50+0.21 days, respectively. The estrous cycle was observed in 79.45 % cows. The remaining cows showed 11-17 (5.48%), 26-36 (9.59%) and 3760 (5.48 %) days of estrous cycle length. The conception rate of observed to be 67.00 +0.26 %. The mean calving to service period found to be 81.18+ 1.62 days in lactating multiparous Ongole cows. Conclusion: It may be concluded that double injection of Prostaglandin has reduced the calving to service period which would even truly reduce calving interval in lactating Ongole cows.