The Relationship between Body Conformation, Testicular Traits and Serum Testosterone Levels in Pre-pubertal Male Boer Goat Crosses

Abstract

In the present study, the relationship among body conformation traits, scrotal circumference and serum testosterone concentrations were investigated in pre pubertal male Boer goat crosses at the Caprine Research and Education Unit Tuskegee University, Tuskegee, Alabama. Body conformation traits (chest girth -CG, height at withers-HTW, body length -BL, body condition scores -BCS, body weight – BW, shoulder width –SW), and scrotal circumference –SC were monitored at week intervals for 12 weeks. Also, blood samples were collected and a calibrated IMMULITE 1000 assay system was used for the quantitative measurement of total serum testosterone levels (TT). Although, results show a non-significant relationship between TT levels and many body conformation traits, serum testosterone levels were lowly and positively correlated to BL (r = 0.19), BW (r = 0.19). Whereas, CG (r= 0.13), HTW (r= 0.11) and SC (r = 0.18) were non-significant. SC was moderately correlated to BL (r = 0.30; P= 0.001) and SW(r = 0.33; P< .001) and strongly correlated with BW (0.61), CG (r = 0.53), HTW (r = 0.41) respectively. In addition, SC and BW increased (P<.01) linearly from week 6 through 1. It is speculated that the week 9 peak of TT levels obtained in this study represents the attainment of sexual maturity (puberty) in Boer goat male crosses. Based on the results of this study, we hypothesized that SC measurements, when used in conjunction with TT levels and body conformation traits can be a valuable breeding soundness evaluation tool for selecting or culling breeding Boer goat sires at an early age by limited resource producers.