早胜牛母牛体重与体尺性状相关回归分析

Correlation regression analysis between body weight and body size traits in Zaosheng cows

为了阐明不同月龄早胜牛母牛体重与体尺指标之间的关系,以建立不同月龄早胜牛的体重估测模型,试验分别测定了12月龄(233头)、18月龄(514头)和24月龄(797头)共1544头早胜牛母牛的体重(Y)、体高(X_(1))、体斜长(X_(2))、胸围(X_(3))和管围(X_(4))指标,并进行了相关分析、通径分析和逐步回归分析。结果表明:12,18,24月龄早胜牛母牛体重与体尺指标均呈极显著正相关(P<0.01),其中均与胸围的相关性最高,相关系数分别为0.947,0.848,0.908;12,18,24月龄早胜牛母牛体尺指标间均呈极显著正相关(P<0.01);12,18,24月龄早胜牛母牛体尺指标对体重的直接影响由大到小均依次为胸围(0.677,0.409,0.574)、体斜长(0.188,0.394,0.378)、体高(0.134,0.255,0.048)和管围(0.057,-0.015,-0.009);12月龄早胜牛母牛体斜长对体重的间接影响最大,胸围对体重的间接影响最小;18,24月龄早胜牛母牛体高对体重的间接影响最大,管围对体重的间接影响最小;建立了12,18,24月龄早胜牛母牛体重预测多元线性回归模型,分别为Y=93.023+0.717X_(1)+0.229X_(2)+0.171X_(3)+0.285X_(4)、Y=107.257+0.652X_(1)+0.571X_(2)+0.448X_(3)、Y=-245.280+2.430X_(1)+1.519X_(2)+0.182X_(3),3个模型的R2分别为0.925,0.872,0.880,拟合度较高。说明可通过测定早胜牛母牛胸围、体斜长和体高指标,利用上述不同月龄的体重回归模型估测其体重。

To elucidate the relationship between body weight and body size indicators in Zaosheng cows with different ages and establish weight estimation models of Zaosheng cows at different ages,the body weight(Y),body height(X_(1)),body slant length(X_(2)),chest circumference(X_(3)),and girth circumference(X_(4))of 1544 Zaosheng cows aged 12 months(233 cows),18 months(514 cows)and 24 months(797 cows)were measured,and correlation analysis,path analysis,and stepwise regression analysis were conducted.The results showed that there were significant positive correlation between body weight and body size indicators at 12,18,and 24-month old cows(P<0.01),and the correlation between body weight and chest circumference was the highest.Their correlation coefficients were 0.947,0.848,and 0.908,respectively.There was a significant positive correlation among the body size indexes of 12,18,and 24-month old Zaosheng cows(P<0.01).The direct impact of body size indicators on body weight 12,18,24 month old cows from large to small,was chest circumference(0.677,0.409,0.574),body slant length(0.188,0.394,0.378),body height(0.134,0.255,0.048),and girth circumference(0.057,-0.015,-0.009).At 12 months,body slant length had the greatest indirect impact on body weight,while chest circumference had the smallest impact.At 18 and 24 months,body height had the greatest indirect impact on body weight,and girth circumference had the smallest impact.Multivariate linear regression models for predicting body weight at 12,18,and 24 months were established as follows:Y=93.023+0.717X_(1)+0.229X_(2)+0.171X_(3)+0.285X_(4),Y=107.257+0.652X_(1)+0.571X_(2)+0.448X_(3),Y=-245.28+2.430X_(1)+1.519X_(2)+0.182X_(3).The fitting(R2)for the three models were 0.925,0.872,and 0.880,respectively,indicating a high degree of fit.The results indicated that body weight was estimated by measuring chest girth,body diagonal length and body height with the help of the above regression model for weight of Zaosheng cows at different months of age.