EFFECT OF GONADOTROPIN-RELEASING-HORMONE (GNRH) ON SUPEROVULATION RESPONSE, EMBRYO RECOVERY AND THEIR QUALITY IN CROSSBRED CATTLE IN THE TROPICS

Effect of gonadotrophin-releasing hormone (GnRH) on superovulation res ponse, embryo recovery and their quality in ccossbred cattle under tro pical climate was studied. The ovulation rate was higher in PMSG + GnR H groups (6.62 +/- .38) than in PMSG group (4.00 +/- 1.77), while it d id not differ between FSH-P + GnRH and FSH-P group. The number of unov ulated large follicles were considerably reduced in-both the GnRH-trea ted groups. The plasma progesterone concentration on the day of flushi ng was higher in PMSG + GnRH group than in PMSG group. This correspond ed with the higher ovulation rate recorded in this group. However, it did not differ between FSH-P + GnRH and FSH-P. Animals responding to s uperovulation were higher in PMSG + GnRH group (87.5%) than in PMSG (5 0.0%) group; however, it did not differ between FSH-P and FSH-P + GnRH group embryo recovery (%), donors yielding eggs (%), and average numb er of total and fertilized eggs were higher in GnRH-groups than in PMS G and FSH-P group. Better superovulation response and higher embryo pr oduction in GnRH-treated animals suggested its beneficial effect.