Determination of camel weight regression equation using biometrical traits of Yazdi camels breed by multivariate linear regression analysis based on the principal components analysis

The objective of the current study was to determine the live body weight regression equation using four traits including bodylength, heart circumference, height of withers and abdominal circumference in 150 camels of Yazdi breed. It was tried to describe the adequate details about an appropriate method for fixing or decreasing the problems of collinearity instability and correlation between independent variables related to live body weight of Yazdi camel ecotype. The results of this study showed that the problem of multicollinearity within the data was associated to body weight of Yazdi camel breed and related independent variables could be fixed by the principal components analysis. Among the independent variables, body height and abdominal circumference had the highest and lowest coefficient in estimating the body weight of Yazdi camel, respectively. It suggested that the principal components analysis be used when there is the problem of collinearity in multivariable linearly regression analysis because of more precise estimation than least squares method. Also this method can help to the breeders to select the best animals by predicting the precise value of some important traits and selecting the best independent variables for predicting the traits