POSTLACTATIONAL ESTRUS REACTION AND SOWS FARROWING RATE IN COLD AND WARM SEASONE

The effects of the warm and cold period of the year on the sows postlactational estrus reaction and farrowing rate, were investigated on an intensive pig production farm unit in Vojvodina. Average weaning-to-estrs interval duration was significantly (P>0.01) longer (8.1 vs. 6.0 days) and farrowing rate was significantly (P>0.05) lower (72.9% vs.80.2%) in worm compared with cold season. The present results support the findings of other authors that higher temperature and extended photoperiod, during summer months, are the main factors influencing reduction the reproductive parameters in the breeding sows herds. This phenomenon is known as a “summer sows infertility”.