POSTWEANING ESTRUS REACTION of sows after the treat MeNT with eCG IN WARM AND COOL SEASONS

Numerous studies show significantly reduced sow fertility in the warm period of the year. The aim of this study was to investigate the effect of sow treatment with eCG preparation, 24h after weaning, on the estrous reaction level. A significantly (p<0.01) higher number of sows, treated with single eCG injection of 1,000IU (primiparous) or 1,500IU (older sows), manifested estrus within 7 days after weaning (83.7%)in comparison with the sows which were not treated (63.9%). In addition, the treatment with eCG results in a high level of estrus synchronization, both in the warmer and in the cooler season of the year. Namely, on day 4 and day 5 after weaning, estrus was detected in 81% of eCG treated sows within the cooler season, and in 78% of sows treated in the warmer season. These values were significantly (p