[Progesterone and estradiol levels in blood plasma of calves following superovulation treatment].

Studies into quantitative behaviours of oestradiol and progesterone in the blood plasma of six heads of prepuberal cattle, following superovulation treatment, using pregnant-mare serum gonadotropin (PMSG) and human chorionic gonadotropin (HCG) have shown the oestradiol concentrations to double, as early as two days after PMSG, and to go up to ten times their original values, after another four days had elapsed. Progesterone values increased, as early as along with induced oestrus, and, consequently, suggested scatter of the ovulation process. The maximum progesterone levels reached something in the vicinity of 100 ng/ml, following superovulation, and, consequently, were far in excess of anything recordable from spontaneously ovulating cyclic cattle. Hormone analyses were continued over six weeks from induced oestrus and superovulation, with evidence being produced to the effect that no permanent cyclic activity had been introduced. All calves rather returned to their prepuberal condition.