Predicting the normal growth curve of calves of Yanbian yellow cattle using compound regression function

the compound regression equation (y=a+b(x-x0)....) was fitted to estimate the body sizes using 66 actual measurements of average body weight and sizes of Yanbian yellow cattle at the age of 24 mo. The results showed that the square of differences between measurements and estimation and the deviation of the point of inflection for male and female calves were 286.56, 0.7 mo and 176.24, 0.3 mo, respectively, the square of differences between measurements and estimation using compound regression equation for male and female was 5214.23, 4007.05 less than that of (y=k/(1+ae.....); the standard error of compound regression equation for the prediction of body measurements was lower than that of (y=a+bx+cx..) except chest width of cows, which fitted well to the actual measurements and eliminate the biases of quadratic polynomial and Blaudi regression equation.