EFFECT OF SEASON ON SUPEROVULATION RESPONSE, RECOVERY RATE AND QUALITY OF EMBRYO IN CROSSBRED CATTLE

Effect of season (hot dry, hot humid and winter) on superovulation res ponse,embryo recovery rate and their quality in crossbred cattle in tr opics was studied using 40 mg FSH-P. The ovulation rate, donors respon ding to superovulation (%), donors yielding eggs (%), embryo recovery (%) and average number of total, fertilized and transferable embryos p er donor were higher in winter (7.62 +/- 1.69, 97.5, 71.42, 40.98, 3.5 7 +/- 1.82, 3.00 +/- 1.75, 1.57 +/- 1.45) than hot dry (6.5 +/- 2.54, 50.0, 50.0, 10.0, 0.75 +/- 0.47, 0.75 +/- 0.47, 0.75 +/- 0.47) and hot humid (6.75 +/- 1.02, 87.5, 57.4, 23.07, 1.71 +/- 0.83, 1.57 +/- 0.84 , 1.00 +/- 0.94) seasons. Blood plasma progesterone concentration on t he day of initiation of superovulation treatment, a day prior and on t he day of PGF-2 alpha injection did not differ significantly among the seasons and the control. Mean concentration of oestradiol 17-beta at superovulatory oestrous and plasma progesterone on the day of flushing were significantly higher (P<0.05) in gonadotrophin-treated groups du ring all the 3 seasons. Winter season appeared to be favourable for in duction of superovulation and production of embryos.