Читать книгу Bovine Reproduction - Группа авторов - Страница 205

Testicular degeneration may be temporary or permanent; temporary degeneration is much more common and, with removal of underlying cause, testis structure and function often recover. It may be difficult to distinguish between degeneration and a severe disturbance of spermatogenesis, with a marked decline in semen quality. The term “degeneration” is somewhat arbitrary, but usually implies reduction in scrotal circumference, testes may be soft, and sperm quality is poor (usually <20% morphologically normal). With temporary degeneration, there is loss of germinal cell layers near the lumen in many or all seminiferous tubules. Sertoli cells and spermatogonia, which are more resistant to damage, are likely to be retained and if the cause of degeneration is removed, tubules are repopulated with spermatocytes and spermatids, restoring testis size and semen quality. Advanced degenerative changes causing permanent damage include spermiostasis, tubular mineralization, granuloma formation, thickened basement membranes, and fibrosis in focal or diffuse areas of testicular parenchyma.