Fertility after estrous cycle control using gonadotropin and prostaglandin F2 alpha treatment of sows.

Two experiments were conducted to determine farrowing rates in sows after estrus and ovulation were controlled by the use ofgonadotropins and prostaglandin F2a (PGF2a). Accessory corpora lutea (CL) were induced in 74 Yorkshire and Duroc sows by an injection of 1,500 IU of pregnant mare serum gonadotropin (PMSG) followed 72 hr later by 750 IU of human %horionic gonadotropin (HCG). Thirtyeight sows (Experiment 1) were injected on days 13 and 14 after HCG with 10 mg and 5 mg of PGF2a , respectively. Sows were artificially inseminated on the second day of estrus after PGF2a treatment with 6 billion spermatozoa in the Behsville L-1 extender. Three groups of 12 sows each were used in Experiment 2. Group 2-1 sows were treated and inseminated as described for sows in Experiment 1. Groups 2-2 and 2-3 sows were injected on days 13 and 14 after HCG with 10 mg of PGF2a and were injected at the time of a second PGF2a injection with 1,000 IU of PMSG followed by 500 IU of HCG either 72 hr later (Group 2-2) or 96 hr later (Group 2-3). Groups 2-2 and 2-3 sows were artificially inseminated 30 to 32 hr after the 500 IU of HCG. Plasma progesterone was