Abstract
To establish a fixed-time artificial insemination (AI) protocol in pigs after treatment for synchronization of ovulation with a combination of prostaglandin F2α (PGF2α), equine chorionic gonadotropin and human chorionic gonadotropin (hCG), we investigated the reproductive hormone profiles and ovulation in the synchronized sows and determined a satisfactory timing for a single AI to provide sufficient reproductive performance. Plasma progesterone concentrations significantly decreased on the day following PGF2α treatment. A preovulatory surge of luteinizing hormone was observed in all synchronized sows, peaking at 26.0±1.2 hours after hCG treatment, and ovulation was detected at 44.8±2.3 hours after treatment. When a timed AI was performed once at 24 or 36 hours after hCG treatment, normal blastcysts were collected from all of the synchronized pigs. Moreover, farrowing rate and average litter size did not differ between the synchronized pigs inseminated once at 24 or 36 hours after hCG treatment and cyclic pigs inseminated multiple times during natural estrus.
