中文摘要：

为进一步了解母猪的繁殖规律,为种母猪选育提供参考依据。文章分析了2005—2013年间杜洛克、长白、大约克母猪9720胎次的妊娠期情况,结果表明,品种、血统、分娩季节、分娩年份和分娩胎次对妊娠期均有极显著的影响（P〈0.01）。长白猪平均妊娠期最长,为116.53 d,大约克114.17 d,杜洛克113.52 d;夏秋季节（6—11月）分娩妊娠期最短;前三胎中,初产妊娠期最长,第二胎最短;父本血统显著影响杜洛克母猪妊娠期,妊娠期最大差值达到1.25 d;随着逐年选育,杜洛克、长白和大约克母猪妊娠天数有逐渐缩短的趋势。

英文摘要：

To further understand the reproduction traits of sows and provide reference for pig breeding,9720 records of gestation length（ GL） for Duroc,Landrace and Large White sows from a pig farm during 2005 to 2013 in Zhejiang Province were analyzed. The results indicated that variety,pedigree,farrowing season and year,fetal parity had highly significant effects on gestation length（ P〈0. 01）. Among different varieties,Landrace had the longest average gestation length of 116. 53 d,followed by 114. 17 d in Yorkshire and 113. 52 d in Duroc. Sows which gave birth to piglets in warm temperature season from June to November had the shortest gestation length in Zhejiang Province.In the first three parities,sows had the longest gestation length at primiparity,and shortest at the second parity. The gestation length was significantly influenced by paternal pedigrees for 1. 25 d difference in Duroc. In recent years,gestation length had a gradual shortening trend in Duroc,Landrace and Large White sows.