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.
Materials 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 by 2nd 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 37- 60 (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.
Keywords: conception
rate, estrus response, Ongole cows, prostaglandin
