This study employed path coefficient analysis within a structural equation modelling framework to investigate the direct and indirect effects of various morphometric traits on body weight in livestock. Data were collected from 259 goats (Boer and Kalahari Red) and 247 sheep (Dorper, Damara, Swakara, Damara × Dorper), comprising both sexes. Measurements included heart girth, body length, wither height, rump height, tail length, and body condition score (BCS). Correlation and path analyses, implemented in R (v4.5.0) using the lavaan package, were used to identify direct and indirect effects of morphometric traits on body weight. Results showed heart girth as the most reliable and consistent predictor of body weight across species and sexes, with BL and wither height providing additional predictive value, while rump height generally exerted negative direct effects but strong indirect influences. Structural equation models (SEM) indicated better model fit for males than females in both species. Predictive equations incorporating heart girth alone explained up to 95% of the variation in body weight for female sheep, while multi-trait models slightly improved accuracy (R² up to 0.97). For goats, heart girth-based models explained ~ 82% of the variation, with inclusion of body length and wither height improving predictive power (R² up to 0.84). These findings confirm heart girth as the most practical single-trait predictor, while multivariate models incorporating body length and wither height offer improved precision. The study provides simplified and field-friendly equations for body weight estimation, supporting improved livestock management where scales are unavailable.
Charamba et al. (Wed,) studied this question.