摘要
对947头0～24月龄中国荷斯坦牛体高、胸围、体斜长进行测定,用线性回归、二次回归和三次回归方程进行拟合。结果表明:中国荷斯坦牛体高、胸围、体斜长的生长曲线呈抛物线型,三次回归方程拟合结果与实测值吻合度最高。除体高离回归平方和高于二次回归方程外,胸围和体斜长的离回归平方和都明显低于用线性回归和二次回归方程计算的结果,表明三次回归方程曲线拟合效果最好,线性回归方程曲线拟合效果最不理想。体高的拐点月龄为16.5,胸围和体斜长的拐点月龄均为18。
The height at withers, chest circumference and the body length of 947 growing Chinese Holstein from 0 to 24 months were detected and fitted by linear regression, quadratic regression and cubic regression equation. The results showed that the growth curves of height at withers, chest circumference and the body length of Chinese Holstein were the shape of the parabola. The R^2 of cubic regression equation for three body measurements was the highest. Sum of squares of partial regression of cubic regression equation were least for chest circumference and the body length except Sum of squares of partial regression of quadratic regression equation was least for height at withers. This indicated that the cubic regression equation was best and the linear regression equation was worst for the fitting of growth curve of Chinese Holstein. An inflexion was observed at the age of half and 16 months for the height at withers and 18 months for chest circumference and body length of growing Chinese Holstein.
出处
《中国畜牧杂志》
CAS
北大核心
2009年第3期1-4,共4页
Chinese Journal of Animal Science
基金
国家863计划(2008AA10Z144)
扬州大学留学回国人员科研启动基金项目
关键词
体高
胸围
体斜长
生长曲线
中国荷斯坦牛
height at withers
chest circumference
body length
growth curve
Chinese Holstein
