中文摘要：

为了研究胎次对杜洛克、长白和大白母猪繁殖性能的影响,根据江苏省某国家级生猪核心育种场2009—2011年出生的繁殖母猪资料,分别选取128头杜洛克、681头长白和610头大白母猪共7280窝生产数据,统计分析不同胎次母猪的总产仔数、产活仔数、断奶仔猪数、初生窝重及校正21日龄窝重。此外,依据胎次将母猪分为3个繁殖阶段（1-2胎、3-6胎及7-8胎）来探究品种差异对母猪繁殖性能的影响。结果表明：胎次对母猪繁殖性能有显著影响（P〈0.05）,母猪1-4胎的总产仔数、产活仔数、断奶仔猪数及初生窝重随胎次呈增加趋势,第4胎达到高峰,且显著高于其他胎次（P〈0.05）;3-6胎繁殖性能较好,7胎之后出现迅速下降趋势;除在第4胎略有下降外,其他胎次的校正21日龄窝重随胎次递增。品种对母猪繁殖性能的影响显著（P〈0.05）,长白和大白母猪的繁殖性能均极显著高于杜洛克母猪（P〈0.01）;长白母猪的产活仔数和校正21日龄窝重显著高于大白母猪（P〈0.05）,2个品种其他繁殖性能无显著差异（P〉0.05）。综上所述,杜洛克、长白和大白母猪的最佳繁殖胎次为3-6胎,长白猪的繁殖性能总体上优于大白猪,就本试验所在的育种场而言,长白猪可能更适合作为二元母猪生产中的母本。

英文摘要：

To investigate the effect of parities on the reproductive performance of sows,the production records of Duroc（128）,Landrace（681）and Yorkshire（610）sows were collected in a national breeding farm in Jiangsu province from 2009 to 2011,then analyzed the total number born,number born alive,litter size at weaning,newborn litter weight and corrected litter weight at 21 days of different parities.Besides,the sows were divided into three stages（1st to 2nd parities,3rd to 6th parities and 7th to 8th parities）to explore the effects of different breeds on the reproductive performance according to the parities.The results showed that the parities have significant effect on the reproductive performance（P〈0.05）.The total number born,number born alive,litter size at weaning and newborn litter weight of sows were improved gradually from 1st to 4th parity,the peak of which was at the 4th parity,and the reproductive performance of the 4th parity was significantly higher than other parities（P〈0.05）.The reproductive performance of sows from 3rd to 6th was preferable,and then it decreased rapidly after the7 th parity.The corrected litter weight at 21 days of each parity（except for the 4th parity）presented an increasing trend.The breeds also had significant effect on the reproductive performance（P〈0.01）.The reproductive performance of Landrace and Yorkshire sows was significantly higher than that of Duroc sows（P〈0.01）.Landrace sows was significantly higher than Yorkshire sows in total number born and corrected litter weight at 21days（P〈0.05）.In summary,the reproductive performance of 3rd to 6th parities was the best in all three breeds;The reproductive performance of Landrace was superior to Yorkshire in general,so Landrace sows might be more suitable for female parent in the production of two-breed cross sows to this breeding farm.