title: Age-related changes in the Leydig cell population, seminiferous tubules, and sperm production in stallions.
mesh_terms: D000375:Aging; D000818:Animals; D006736:Horses / Q000502:physiology*; D007985:Leydig Cells / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D009929:Organ Size; D012671:Seminiferous Tubules / Q000033:anatomy & histology / Q000502:physiology*; D013091:Spermatogenesis; D013737:Testis / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology*