[Studies on the effect of the HCG injection date on the fertility of ovulation-synchronized gilts].

The time gap between pregnant mare serum gonadotropine injection (PMSG) and subsequent human chorionic gonadotropine injection (HCG) had major effects, within 72 to 80 hours, on the number of animals with recorded toleration reflex to deadline-oriented insemination as well as on actual fertility. Delay of injections within the above limits always led to higher farrowing and piglet rates. HCG injection was round to be optimally timed when 78-80 hours were allowed to elapse from the preceding PMSG injection.