Testicular Biometry and Serum Testosterone Levels in Red Sokoto Bucks Raised in Kaduna State

Testicular measurements and circulating testosterone concentrations serve as reliable indicators of male reproductive potential in small ruminants, with implications for breeding soundness evaluation and flock management. The Red Sokoto goat, valued for its premium leather and meat production, is extensively raised in Kaduna State in Nigeria's North West zone. This study assessed scrotal circumference, testicular length, width, and volume, and correlating these with serum testosterone levels in 60 sexually mature Red Sokoto bucks. Animals were stratified into three age groups: 12 to 18 months, 19 to 30 months, and above 30 months. Testicular dimensions were measured using digital callipers, and volume was estimated by the prolate spheroid formula. Blood samples were collected by jugular venepuncture, and testosterone was quantified by enzyme-linked immunosorbent assay. Results showed significant positive correlations between scrotal circumference and serum testosterone across all age groups. Mean scrotal circumference increased from 19.2 cm in the youngest group to 24.6 cm in bucks above 30 months old. Serum testosterone was significantly higher in animals above 30 months compared with younger bucks. Seasonal effects on testosterone were observed, with peak concentrations recorded during the dry cool season. These findings provide reproductive reference parameters for Red Sokoto bucks that can guide breeding soundness evaluation programmes in Kaduna State and the North West region. Keywords: testicular biometry, testosterone, Red Sokoto goat, reproductive, Kaduna.