Age-dependent phenotypic correlations of body weight and morphometric traits in Nellore brown sheep

The morphometric measurements are extensively utilized as indirect selection traits for predicting body weight and improving growth and productivity in sheep, although their biological relevance varies with age and physiological maturity. The age-specific phenotypic associations between body weight (BW) and morphometric traits (craniofacial, skeletal frame, girth-related, and peripheral traits) were evaluated in Nellore Brown sheep. Data were collected from 86 sheep (31 males and 55 females) and classified into two age groups: Group 1 (Age < 1 year; N=23) and Group 2 (Age > 1 year; N=63). Partial Pearson’s correlation coefficients were estimated separately for each age group while controlling for sex. The BW showed moderate to strong (r>0.4) associations with thoracic and body circumference traits in Group 1. Whereas BW was strongly associated (r>0.6) with chest girth, paunch girth, body length, and withers height in adult age Group 2. The study concluded that girth-related traits are reliable indirect selection criteria for improving body weight in adult sheep.