[Histological characteristics of the testis and epididymis of calves during postnatal development].

A histologic investigation was carried out of the testis and epididymis of a total of 42 calves of the Black-and-white grouped in 14 test groups. The animals were currently castrated after the age of 2 months and were raised in the open. Material for investigation was taken on the 1st and 15th day, and once in every following month up to the completion of 12 months of age. It was found that up to the 3rd month there was no lumen in the testicular tubules, but only differentiating Sertoli cells and gonocytes were seen. Spermatogonia and spermatocytes were first observed at the age of 4 months, and prespermatids and sporadic spermatids--in the 8th month. Single spermatozoa in the phase of final shaping appeared in the 10th month, and completed spermatogenesis--in the 11th month. The histogenesis of the wall of the tubules of the epididymis completed earlier as compared to the histogenesis process in the testis--by the age of 8 months. Later on there were morphologically in the epididymis some proliferation and folding of the tubules with widening of the lumen, whereupon the amount of the surrounding connective tissue relatively decreased.