新太湖猪选育过程中近交技术的应用及效应分析

Application and Effect of Inbreeding in the process of New Taihu Pig Breeding

利用新太湖猪选育过程中（１９８６～１９９４）６个世代母猪的分娩产仔记录，后备猪生长发育测定资料，分析了近交对繁殖性能和生长发育性状的影响。相关分析表明，近交与产仔数、产活仔数的相关系数分别为－０．１６２５、－０．１５４６。与１８０日龄活重、体高、胸围、及８０ｋｇ时背膘厚度的相关系数分别为－０．１３５，－０．２１１，－０．２１８，－０．２０４。回归分析表明，近交系数每上升１０％，产仔数下降０．３９头，１８０日龄活重下降１．５ｋｇ，背膘厚下降０．０７４８ｃｍ。产仔记录分析表明，母猪近交系数在２０％以下时，产仔数比非近交组下降０．２７头，差异不显著（Ｐ＞０．０５）；近交系数在２０％以上时，下降１．３５头，差异不显著（Ｐ＞０．０５）。生长发育性状表明，近交系数在３０％以上时，１２０日龄活重、１８０日龄活重等性状都显著下降。８０ｋｇ活体背膘厚当个体近交系数上升到２０％以上时，与非近交组相比下降０．１６ｃｍ，差异显著（Ｐ＜０．０５）。

Reproductive and growth records of 6 generations of New Taihu Pig were analysed to study the influence of inbreeding on its performances.The results showed that correlation coefficients of inbreeding coefficient with litter size and live litter size were -0 1625、-0 1546 respectively. Correlation coefficients of inbreeding coefficient with the weight、height at withers and chest girth at 180 days of age and fat thickness at 80 kg body weight were -0 135,-0 211,-0 218,-0 204.Regression analysis showed that when the inbreeding coefficient raised by 10%,litter size decreased by 0 39,180 days' body weight decreased by 1 5 kg,and fat thickness decreased by 0 0748 cm.Reproductive performance analysis showed that when the inbreeding coefficient of sows was less than 20%,litter size of the sows was 0 27 less than in the non inbreeding group(P>0 05),and when the inbreeding coefficient was more than 20%,litter size was 1.35 less than in the non inbreeding group(P>0 05).The growth performance analysis showed that when inbreeding coefficient was more than 30%,120 and 180 days' body weight and the like descended significantly.When the inbreeding coefficient was more than 20%,fat thickness at 80 kg body weight in the inbreeding group was 0 16 cm lower than that in the non inbreeding group(P<0 05).