Progesterone profile during estrus cycle in different breeds of cow under tropical climate

Abstract

Progesterone profile in Holstein Friesian (HF;15), Halfbred (FxH; 20) and Hariana (13) cows was estimated at a organized farm under tropical climate. Study was carried out throughout a year, which was divided into 3 different seasons, viz. cool comfortable, hot dry and hot humid based on atmospheric temperature and relative humidity. Progesterone concentration was estimated in blood plasma collected on alternate days starting from day of oestrus to day 21 or up to the day of subsequent oestrus. Cows were selected in oestrus by parading a teaser bull 3-times a day. Peak values of progesterone concentration were observed 6.20±0.38 and 6.09±0.23 ng/ml on day 15 of estrus cycle in Holstein Friesian and halfbred cows, respectively, during cool comfortable season, whereas 5.45±0.34 ng/ml on day 13 in Hariana cows. The trend was similar in other seasons also. Concentrations were significantly higher during cool comfortable seasons also. Concentrations were significantly higher during cool comfortable season than that in hot dry and hot humid seasons in Holstein Friesian cows. Difference was noticed from day 7 to day 15 of estrus cycle. In contrast to Holstein Friesian, progesterone concentration was significantly higher in halfbred cows during cool comfortable season compared to hot dry season only from day 5 to day 15, although difference was marked from day 3. However, it was similar to hot humid season from day 7 to day 21. In Hariana cows, the concentration was nonsignificantly higher during cool comfortable season than other 2 seasons on most of the days from day 5 to day 21. Thus the study revealed that in Holstein Friesian cows, progesterone concentration during estrus cycle is affected by both high temperature and humidity whereas in halfbred cows only by high temperature, which affects reproductive activity in these breeds accordingly.