Using factor analysis to characterise the body structure of male and female indigenous Tswana goat at kid and grower ages

Abstract

This study was conducted to estimate the relationships among body measurements and determine underlying factors describing the body structure of female and male Tswana goats at kid and grower age-groups. Body-weight (BW), body-length (BL), heart-girth (HG), height-at-withers (HW), shoulder-width (SW), neck-length (NL), tail-length (TL) and ear-length (EL) were recorded from 273 female and 278 male kids, 699 female and 281 male growers. Fifteen farmers keeping goats were randomly selected from each district excluding Tsabong and Ghanzi districts and records taken on a random sample of 4-12 animals per farm in 2001. Data were analysed to determine correlations among the variables and factors explaining the variability in the body structure of Tswana goats were extracted. Significant (P<0.05) strong and positive correlations (r=0.81 to 0.89) of BW to BL, HW and HG in male and female kids and male growers were found. There were significant weak to moderate correlations (r=0.21 to 0.51) between BW and SW while in female growers, the correlation between BW and HW was not significant (P>0.05). In female kids general body size factor explained 54% of the variation in body structure. For male kids and growers, general body size and shoulder width factors explained 72.3% and 61.3% of the variation respectively. Neck-length, body shape and shoulder-width factors explained 58.4% of the body variation in female growers. The identified one to three factors (height at withers, heart girth, shoulder width and body length) described the body structure of the Tswana goats and have potential use in selection for improved productivity.