Effect of exogenous gonadotropins on the weaning-to-estrus interval in sows.

摘要

70 lactating American Yorkshire sows (average parity = 4.6) were dried off after 27.7±0.4 days of lactation and injected with prostaglandin 600 (400 IU PMSG + 200 IU HCG) or 0.9% saline (controls). Prostaglandin treatment increased the percentage ofsows in oestrus within 7 days of weaning (97.1 vs. 82.9; P<0.05). Compared with controls, treated animals showed oestrus sooner (3.8±0.1 vs. 4.5±0.1 days; P< 0.01). Sows exhibiting oestrus within 7 days of treatment were artificially inseminated 0 and 24 h after first exhibiting oestrus. Farrowing rate tended to be higher in control than treated sows (96.6 vs. 82.3%). The number of pigs born alive was similar for the 2 groups (12.7±0.6 and 11.7±0.7). Piglets farrowed by control sows tended to be heavier than those from treated sows (1.49±0.06 kg vs. 1.34±0.06 kg).