Ovulation in prenatally androgenized ewes

The ovarian activity of prenatally androgenized ewes was studied by measuring plasma progesterone concentrations in daily samples of peripheral blood, and by examining the ovaries at laparotomy. Ewes that were exposed to testosterone between days 30 and 80, 50 and 100 or 70 and 120 of foetal life by implanting their mothers with 1 g testosterone, failed to show regular overt oestrous cycles, although some of them ovulated, whereas ewes exposed to testosterone between days 90 and 140 of foetal life had normal oestrous cycles. The incidence of ovulatory failure appeared to increase with age in ewes treated between days 50 and 100 or days 70 and 120 of foetal life.