Relationship between serum testosterone levels and morphometric indices in Ongole bulls

Abstract

The study evaluated the relationship between serum testosterone concentration and morphometric traits in Ongole breeding bulls. Six breeding bulls were included in the study. Serum testosterone (nmol/L) was quantified via ELISA, while scrotal circumference, body girth and body length were measured; body weight was derived using Shaffer’s formula. Testosterone demonstrated statistically significant correlations with age (r=0.918) and scrotal circumference (r=0.915), while body girth (r=0.622) length (r=0.586) and calculated body weight (r=0.566) showed non-significant moderate trends. With regression analysis it was elucidated that age (R²=0.843) and scrotal circumference (R²=0.837) independently accounted for the variation in testosterone while scrotal circumference emerged to be a more practical selection trait. Inversely, scrotal circumference depends on the testosterone concentration, establishing bi-directional relationship. The findings suggest that scrotal circumference might be considered as a useful morphometric biomarker for testosterone, thereby for evaluating the endocrine and reproductive potential of breeding bulls.