A study on the factors influencing resumption of postpartum ovarian activity in crossbred cows*

The aim of the study was to identify the factors influencing postpartum resumption of ovarian activity in crossbred cows. Sixty crossbred cows on day 30 postpartum were selected and the details of age, parity, milk yield, peripartum and postpartum complications were recorded. Animals were examined per rectally from 30 to 90 days postpartum at 12 days interval for the presence of corpus luteum (CL) of any stage during the period of study. Serum progesterone concentrations were estimated and cows which resumed ovarian activity (progesterone concentration >1 ng/mL) at early and late postpartum periods were identified. Association of age, parity, BCS, milk yield and reproductive complications with postpartum resumption of ovarian activity (ROA) at varying periods was analysed. No significant association between ROA and variables such as age, parity. milk yield and reproductive complications were observed. BCS was significantly (P<0.01) associated with ROA. The higher number of animals with postpartum complications belonged to not resumed period than that of early and late resumed periods. The odds ratio for BCS indicated 6.46 times risk for ROA for every unit increase of BCS