A study was conducted to evaluate the influence of non-genetic factors on production performance in pigs, including piglet body weight, litter size, and litter weight. A total of 180 farrowing records collected over a ten-year period (2014-2023) in Tamil Nadu, India were used for the analysis. The data were analyzed using the General Linear Model (GLM) procedure. The results showed that season and parity had a significant effect (P < 0.01) on the traits studied. The highest birth weight of piglets was observed during the North East Monsoon (NEM), followed by summer and the South West Monsoon (SWM) seasons. In contrast, the highest weaning weight was recorded during the South West Monsoon season, followed by summer, winter, and the North East Monsoon. An increasing trend in both birth weight and weaning weight was observed from the first to the seventh parity, with statistically significant differences among parities (P < 0.01). Similarly, higher weaning weights were recorded in the first three parities of the sow, likely to be due to the uniform birth weights of piglets within the litter. The highest litter weight was observed in the seventh parity, and a better growth rate was noted at weaning, with significant differences (P < 0.01). Although litter size showed some variation, it did not affect the litter size at weaning. It is suggested to breeding of sows at earlier than usual in favorable season and it can be maintained up to seventh parity or at the age of four years old.
THIRUNAVUKKARASU et al. (Tue,) studied this question.