Reproductive performance of purebred landrace and Yorkshire sows in Thailand with special reference to seasonal influence and parity number.

摘要: The purpose of this study was to analyze reproductive performance in purebred Landrace and Yorkshire sows with special reference seasonal influence parity number, under tropical conditions where day length is almost constant throughout the year. Data from three sow herds Thailand during period 1993 1996 were analyzed. two breeds present all herds. analysis comprised records 3848 litters 2033 litters. statistical models included fixed effects month, year, parity, breed sow, herd, two-way interactions breed-parity, breed-herd, breed-month, breed-year, parity-month, month-herd, year-herd month-year. random effect within models. Analysis covariance performed temperature, humidity heat index on number total born per litter (NTB), weaning first service interval (WSI) farrowing rate (FR). had significantly higher NTB (0.6 piglets), live (0.5 average birth weight (0.13 kg) than (P<0.001). Farrowing 3.9% (P<0.01). However, shorter WSI (P<0.001) proportion served 7 days after (P<0.01) sows. No differences found stillborn conception interval. Parity significant parameters Number lower for rainy season other seasons. low mated hot season. Weaning WSI7 prolonged weaned Reproductive unfavorably influenced by elevated temperature mating (NTB FR) or lactation (WSI).