Reproductive performance in sows treated with estradiol benzoate/human chorionic gonadotrophin combination at weaning.

The effects of estradiol benzoate plus human chorionic gonadotrophin administered on the day of weaning on the reproductive performance in sows was studied. The treatment advanced the onset of estrus but the duration of estrus was slightly prolonged. Breeding on the post-weaning estrus was associated with poor pregnancy rate and smaller litters. The treatment did not cause permanent damage to the reproductive tract as the reproductive performance of the treated sows after subsequent breedings were unaffected. The possible causes of the poor fertility in the estradiol benzoate plus human chorionic gonadotrophin treated sows are discussed.