Department of Animal Physiology, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati - 781022, India.
*Department of Veterinary Gynaecology, Obst. and A I, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati - 781022, India.
The reproductive activities like oestrus, conception and cyclicity in postpartum anoestrus cows following Crestar ear implant and PMSG injecfion were studied. Out of 10 postpartum anoestrus cows, 9 exhibited oestrus 30.81±1.43 hours after Crestar ear implant was removed after 9 days with PMSG injection @ 300 1U on the day of implant removal. The duration of induced oestrus was 19.11±0.34 hours. All oestrus cows had ovulated. Five out of 9 cows conceived at induced oestrus. Four animals which did not conceive, exhibited first natural oestrus after 20.8±3.61 days. Out of these four cows, only three conceived. The remaining one cow resumed normal cyclicity.The animals completed their term on an average 280.44±2.35 days after insemination. The mean birth weight of calf was 10.56±1.32 kg with male and female ratio of 1:3.
