胎次和配种季节对美系大白母猪妊娠期及产仔性能的影响.

[Objective]In order to optimize parity structure and mating time of pig population, the effects of parity and mating season on gestation length and litter performance were studied. [Method]A reproductive record of total 3278 parities in 2016-2017 years for American Large White Sows from breeding pig faom of Yunnan Huijia Breeding Company Limited was analyzed. [Result] The breeding season had significant effect on the total litter size, the number of live litters（P <0.05）. The total number born and number born alive of sows in spring were significantly higher than those in summer and autumn（P <0.05）. It had significant difference under different parities for the total number born number born alive number of stillbirths, gestation period and so on（P<0.05）. The litter performance of the 3rd-5th parities and the 7th parity was better than that of other parities. [Conclusion] The best reproductive performance of the American White Sows is the 3rd, 4th, 5th and 7th parities, and the mating performance of sows in spring is better than that in other seasons. [ABSTRACT FROM AUTHOR]