Testicular biometry and seasonal variations in semen parameters of Black Bengal goats

Abstract

Body weight, growth rate and testicular biometry of Black Bengal bucks (19) belonging to different age groups were studied. Further, this study was extended to delineate the histological changes in the testes with advancement of ages and to evaluate the seasonal variations in the important semen parameters. The body weight differed significantly across the age groups but the body weight gain (g/d) was higher in the age groups of 0–4 and 17–20 months. The mean scrotal circumference increased with the advancement of age and attained maximum circumference at the age of 12 months. The mean testicular diameter increased significantly till 10th month of age. All these biometrical parameters were highly correlated with each other, and with age and body weight. The histological examination of testes revealed an effect of age on the seminiferous tubules and stages of the spermiogenesis. At 3.5 months of age, lumen of seminiferous tubules became distinct with the abundance of spermatozoa. These observations along with testicular biometry indicated the age at which bucks attained puberty. Significant effect of the seasons (e.g., spring and summer) was observed on the semen parameters with the improvement in the progressive motility, percentage of live spermatozoa, chromatin integrity and a drop in membrane integrity during summer. These results will provide an important impetus in selection of breeding bucks of Black Bengal breed.