Progesterone decreases calving interval. a preliminary study

ABSTRACT

This experimental study on 18 cows was carried from February to June, 1995. Progesterone was administered [25 mg] to each cow on alternate days for 11 days and this oestrus symptoms were observed from day 12 to 14. Sixteen [88.9%] animals showed oestrus through physical symptoms and the oestrus of 15 [83.3%] animals were diagnosed with milk progesterone level [<2ng/ml]. Natural breeding was only allowed to animals at proper oestrus. On 22nd day of insemination, milk progesterone >7ng/ml was found in 13 [72.2%] animals while rectal examination on day 60 of breeding showed 12 [66.7%] animals to be pregnant. However, both methods demonstrated that progesterone decreases calving interval by exhibiting early oestrus