Concentration of serum estradiol, progesterone and cortisol during biological stress period of normal cyclic and silent Oestrous crossbred cows of Assam

Abstract

The present study was planned to compare the concentration of serum estradiol, progesterone and cortisol level during biological stress period of normal cyclic and silent oestrous cycles of crossbred cows of Assam. Jugular blood samples were collected from ten normal cyclic and ten silent oestrous cows on day 0, 10, 17 and 20 of cycles for the present study. These 3 hormones were estimated by using ELISA kit manufactured by LDN GmbH& Co.KG, Germany, by solid phase enzyme-linked immunosorbent assay. Both estradiol and progesterone concentrations in serum were varied significantly (P< 0.01) between days of oestrous cycles of normal and silent oestrous cows. Lowest level of progesterone with concomitant highest level of estradiol was recorded on the day of oestrus. On the other hand, highest concentration of progesterone was found on the day 10 of cycles with lowest concentration of estradiol on day 17 of cycle. The mean levels of cortisol varied significantly between days of cycles with highest level on the day of oestrus.