SCROTAL AND TESTICULAR DIMENSIONS IN SOME WEST AFRICAN BULLS

Résumé

A series of studies were  conducted to estimate testicular size from scrotal measurement and determine the relationship between testicular size, age and liveweight in some West African bulls. Repeatability estimate for scrotal circumference measurements between technicians was 0.96. scrotal circumference was highly correlated to paired testes weight (r = 0.88) and volume (r = 0.87). Testes weight and volume were reclosely related (r = 0.997) but their ration (g/cc)varied in 30 bulls from 0.962 to 1.119, with a mean and standard deviation of 1.027 + 0.029. The regression equation for estimating tests weight (Y) from scrotal circumference (X) was Y = 506.17 + 27.70X. Significant correlations existed between scrotal circumference and age (r from 0.59 to 0.79) or liveweight (r from 0.62 to 0.83) in N Dama, Bunaji and Sokoto-Gudali bulls. However, examination of the partial correlations showed that most of the age effects were attributable to changes in liveweight. Limited evidence indicate that young Bunaji bulls have larger testis than the other two breeds although they may be overtaken by Sokoto-Gudali bulls after 5 years of age