Prediction of body weight from testicular and morphological characteristics in indigenous mengali sheep of Pakistan using factor analysis scores in multiple linear regression analysis

The objective of the investigation was to predict body weight (BW) from testicular and morphological characteristics of the indigenous Mengali Sheep in Balochistan, Pakistan. The characteristics recorded were: body weight (BW), testicular length (TL), scrotal length (SL), scrotal circumference (SC), body length (BL), withers height (WH) and heart girth (HG) of 107 indigenous Mengali sheep in age range of 12 to 48 months. Only multiple linear regression analysis fitting to the available data showed tendency to multicollinearity problem with VIF >10 and didn't present optimal solutions. With the purpose of removing the multicollinearity problem and especially making more correct interpretation biologically, the data were exposed to a combination of Factor and Multiple Linear Regression analyses. The appropriateness of factor analysis for the current data was determined by using criteria such as Kaiser-Meyer Olkin (KMO) measure of sampling adequacy and Bartlett's test of spherity. These criteria showed that the data were appropriate for the factor analysis, one of the multivariate statistical analysis techniques. Thereafter, the factor analysis was applied to explanatory variables in order to derive new-uncorrelated latent explanatory variables from the variables. In the factor analysis, three new latent variables whose eigenvalues were greater than one were considered as explanatory variable for multiple linear regression analysis. Results obviously illustrated that 79.1% of variation in body weight was effectively explained by these new latent explanatory variables. Consequently, if confirmed at genetic level, the testicular and body traits might provide a significant contribution in the genetic improvement of the body weight of the indigenous Mengali for sheep breeding. © 2012 Friends Science Publishers