Études des paramètres morpho-pondéraux chez les ovins de la race EL-Hamra. Application des arbres de décision CART pour la prédiction du poids vif chez les brebis

Abstract

This study is a contribution to the phenotypic characterization of the El-Hamra sheep breed raised at the ITELV demonstration farm in Ain El Hedjar, Saïda province, Algeria. The aim of this study is to provide additional information on the morpho-weight characteristics of males and females El-Hamra sheep. We measured the live body weight (LTRC) of the animals as well as 8 quantitative morphological traits: Total length (LP), trunk length (PP), chest width (TO), chest depth (HG), chest girth (HS), height at withers (HW), and height at sacrum (HS). A total of 61 adult animals were used in this study (40 ewes and 21 rams). The Classification and Regression Tree (CART) technique was applied to determine the LW from the body measurements. The results show that the strongest relationship (r=0.789, P<0.01) observed in females was between LW and TL, while in males, the strongest relationship (r=0.836, P<0.01) was observed between CG and LW. The CART model proposed for predicting LW in ewes shows good performance, indicated by high R² and adjusted R² values of 0.792 and 0.746, respectively, and an RMSE value of 2.906. The results suggest that the proposed CART model could be considered suitable for predicting live weight in El-Hamra ewes.