Induction and Control of Ovulation in Swine

Abstract
Follicles capable of ovulation were developed in gilts 5 or 6 days after withdrawal of oral administration of 500 mg. of 6α-methyl-17α-hydroxyprogesterone acetate per female per day for 8, 9 or 10 days. These follicles began to ovulate spontaneously in some gilts about 10 days after treatment but ovulation had not occurred before 18 days after treatment in other cases. Injection of 250 to 2000 i.u. of HCG 5, 6, 7 or 8 days after treatment caused ovulation in 94% of animals 40 hours after the injection. Four percent of the animals showed heat at this ovulation while 71% showed heat 21, 22 or 23 days later. Forty-three percent showed heat in 48 hours when injected subcutaneously with 50 or 100 mg. of diethylstilbestrol. Copyright © . .