Estimation of live weights at the beginning and the end of grazing season in Tuj lambs via scores of factor analysis

Abstract

This study was conducted in order to eliminate multicollmeanty between body measurements of Tuj lambs and to estimate their live weights in the beginning and the end of grazing season (GS) using factor analysis scores, which were determined by calculating some body measurements, in multiple regression model. For this purpose, the matenal of the study consisted of 297 Tuj lambs born between 2009 and 2013. Live weights (LW) of lambs in the beginning and at the end of GS and body length (BL), withers height (WH), chest girth (CG), chest depth (CD), circumferences of cannon forelimb (CCF) and circumferences cannon hmdlimb (CCH) measurements were analyzed m the study. Factor analysis were used to determine the estimated equation between the characteristics. It was determined that there was a multicollinearity between, CCF and CCH measured at the beginning of GS. Problem of multicollinearity between independent vanables was eliminated by using factor scores (FS) determined by factor analysis in multiple regression models. Consequently, two factors were detected from results of factor analysis applied to body measurements to determine live weights of Tuj lambs m the beginning and at the end of GS. These factors for LW m the beginning and at the end of GS were found to explain 84 8% and 78 9% of total variance, respectively. Thereby, it was revealed that more accurate estimations could be made by using factor analysis scores m estimating live weights of Tuj lambs at the beginning and the end of GS. In addition, it was concluded that applying factor analysis scores denved from independent vanables decreased mistake m the model according to least squares method.