Effect of superovulatory treatment on serum estradiol-17β and progesterone concentration and its correlation with embryo recovery in mithun cows

The present experiment was conducted to observe the effects of superovulatory treatments on serum estradiol-17 beta and progesterone concentration and its correlation with embryo recovery in mithun cows (Bos frontalis). Healthy cyclic mithun cows (20) between second and fifth lactation were randomly divided into 4 groups (n=5) viz. A, B, C and D. Animals were maintained under intensive system of management at NRC on Mithun, Nagaland. Each animal of groups A, B, C and D was treated, respectively, with 400 mg FSH, 300 mg FSH, 400 mg FSH + 1500 IU hCG and 300 mg FSH + 1500 IU hCG in divided and reducing doses during 4 days starting on day 11 of estrous cycle. Prostaglandin F-2 alpha was injected intramuscularly on day 13 of estrous cycle after sixth injection of FSH. hCG was injected intramuscularly 12 h post oestrus. Results revealed that serum oestradiol-17 beta was higher in cows treated with 400 mg FSH compared to 300 mg that became significant on day 4 of treatment in group C (10.20 +/- 0.34 pg/ml) than group B (9.25 +/- 0.35 pg/ml). Significantly higher serum oestradiol was recorded at induced oestrus in all the treatment groups. Serum progesterone level decreased to a significant level on the day of induced oestrus in all the 4 groups irrespective of treatment. Serum oestradiol-17 beta at induced oestrus had positive correlations with the number of total embryos recovered. It may be concluded that the serum estradiol and progesterone concentration are good indicator of embryo recovery in superovulated mithun cows.