Phenotypic Characterization and Weight Estimation of Young Thalli Sheep Through Multivariate Traits

Abstract

The aim of this study was to evaluate the multivariate traits in Thalli sheep for phenotypic characterization and their association with the live bodyweight of the animals for the selection of superior individuals by using the principal component analysis (PCA) technique and regression equation. Twenty-one (21) multivariate traits were taken of young Thalli sheep aged 0-12 months in Thall area of Punjab, Pakistan. Morphometric traits measured were withers height (WH), head width (HW), head length (HL), body length (BL), ear width (EW), ear length (EL), neck width (NW), neck length (NL), heart girth (HG), rump length (RL), tail length (TL), rump width (RW), barrel depth (BD), birth weight (BiW), live body weight (BW), sacral pelvic width (SPW), teat diameter (TED), teat length (TEL), testes length (TsL), scrotal circumference (SC) and testes width (TsW). Positive and highly significant (P≤0.01) correlations among different morphometric traits were present in overall animals of 0-12-month age groups of Thalli sheep such as WH, BL, HL, HW, EL, EW, NL, NW, HG, RL, BD, SPW, BiW and BW. The results of principal component analysis of data for all age groups of young Thalli sheep were showed that three principal components (PCs) were extracted as PC1, PC2, and PC3. For the 0-3-month age group, PC1 showed high variance before and after rotation (44.33% and 37.68%), for 4-6-month age group, PC1 had a high value of variance as 58.45% and PC2 had 15.17%, for 7-9-month age group, three principal components were extracted with high eigenvalues (7.56) for PC1 and high variance 50.45% and for 10-12-month age group, PC1 had a high value of variance as 50.05% and PC2 and PC3 had values as 10.67% and 9.05% respectively and their cumulative variance was 69.79%. Regression equations for all age groups of young Thalli sheep presented a very close relationship between predicted bodyweight and actual live bodyweight. The present study showed that hearth girth, body length, and withers height are very important parameters for the estimation of body weight and phenotypical characterization.