云上黑山羊体尺性状对体重影响的通径分析

旨在利用云上黑山羊体尺性状对体重进行较为准确的估计,剖析云上黑山羊各体尺性状对体重的影响。选取6月龄(n=292)、7月龄(n=46)和成年(n=368)3个阶段的云上黑山羊母羊为试验对象,测定其体长(X1,cm)、体高(X2,cm)、胸围(X3,cm)和管围(X4,cm)4个体尺性状,并记录体重(Y,kg)。利用逐步回归法建立云上黑山羊体尺性状与体重间的多元线性回归方程,运用相关分析和通径分析剖分云上黑山羊体尺性状对体重的影响。结果表明:6月龄、7月龄和成年云上黑山羊母羊体重与体尺性状的多元线性回归方程分别为Y=-39.363+0.521X1+0.530X3、Y=-45.328+0.537X1+0.603X3和Y=-69.131+0.648X1+0.851X3,3个阶段云上黑山羊母羊胸围对体重的直接作用均大于体长对体重的直接作用以及体长通过胸围对体重影响的间接作用。结果提示,本研究建立的3个方程可用于云上黑山羊的选育实践,胸围是影响云上黑山羊母羊体重的主要体尺因素。

Path Analysis on Effects of Body Size Traits on Body Weight of Yunshang Black Goat

A study on Yunshang Black goat was performed to estimate the body weight accurately using body size traits and to analyze the effects of body size traits on body weight.In this study,individuals from three stages including 6-month-old does(n=292),7-month-old does(n=46)and adult does(n=368)were selected to record their body weight(Y,kg)and to measure four body size traits consisting of body length(X 1,cm),body height(X 2,cm),chest circumference(X 3,cm)and cannon circumference(X 4,cm).Stepwise regression method was employed to establish multiple linear regression equations between body size and body weight of Yunshang Black goat.Then,the correlation analysis and path analysis were used to calculate the effects of body size traits on body weight of Yunshang Black goat.The results showed that the multiple linear regression equations of body weight and body size traits of female animals were 6-month-old:Y=-39.363+0.521 X 1+0.530 X 3,7-month-old:Y=-45.328+0.537 X 1+0.603 X 3 and adult:Y=-69.131+0.648 X 1+0.851 X 3,respectively.The direct effects of chest circumference on the body weight of female black goat in three stages were greater than that of body length and the indirect effects of body length through chest circumference.The results suggested that the three equations established in this study could be used for the breeding practice of Yunshang Black goat,and the chest circumference was the main body factor affecting body weight of black goat.