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试验旨在通过大通牦牛体尺性状对其体重做较为准确的估计,剖分牦牛各体尺性状对体重的影响。随机选取了6~12月龄的88头大通牦牛为研究对象,其中公牛48头,母牛40头。测量各牦牛的体长、体高、胸围3个体尺指标,并称量其体重;采用逐步线性回归的方法建立大通牦牛体重与体尺的多元线性回归方程;利用通径分析方法计算各体尺性状对体重的直接作用和间接作用。结果表明:各性状之间的表型相关均达到了极显著水平(P<0.01);大通牦牛公牛和母牛的多元线性回归方程分别为Y=-194.708+0.766X_1+0.782X_2+1.229X_3和Y=-118.056+0.910X_1+1.106X_3,其中Y为体重(kg),X_1为体高(cm),X_2为体长(cm),X_3为胸围(cm),体重估计值与实际观察值差异不显著;胸围对体重的直接作用大于通过其他性状影响体重的间接作用,且胸围的间接作用在体高和体长对体重影响中做了主要贡献。通过研究结果可知,研究所得多元线性方程可以应用于大通牦牛良种选育实践,大通牦牛体重的主要影响因素来自于其胸围指标。
The purpose of this experiment is to make a more accurate estimation of the body weight of the body of the yak by dividing the body size of the yak body weight. Eighty-six Chamaeks yaks aged from 6 to 12 months were randomly selected as study subjects, including 48 bulls and 40 cows. The body length, body height and bust of each yak were measured and their body weights were measured. Multiple linear regression equations of body weight and body size of Datong yak were established by using stepwise linear regression method. Direct and indirect effects on weight. The results showed that the phenotypic correlations of all traits reached extremely significant level (P <0.01). The multiple linear regression equations of Yat Bulls and Dairy Cattle were Y = -194.708 + 0.766X_1 + 0.782X_2 + 1.229X_3 and Y = -118.056 + 0.910X_1 + 1.106X_3, where Y is body weight (kg), X_1 is body height (cm), X_2 is body length (cm) and X_3 is bust (cm). The difference between body weight estimation and actual observation is not significant Significantly, the immediate effect of bust on body weight was greater than the indirect effect of body weight through other traits, and the indirect effect of bust was a major contributor to body weight due to body height and body length. The results show that the multivariate linear equation obtained from the study can be applied to breed breeding of Chase Yak. The main influencing factors of Chase Yak weight are its bust index.