title: Germ cell weakness as a cause of testicular hypoplasia in bulls.
abstract: Sporadic cases of testicular hypoplasia were earlier found in bulls of the Swedish Red and White breed. An accumulation of cases have occurred since 1970 in sons of 2 outstanding progenytested bull sires, 2 F and 27 U, which had a common father, 545 B. The history and clinical examination of affected bulls varied. Some had azoospermia and very small testes at a young age, while others could be normal in all respect when they were young but had a short reproductive life and had to be culled at about 3 years of age. Most of the affected bulls were between these 2 extremes. The histologic examination showed principally different degrees of testicular degeneration. There were always some germ cells left in all affected seminiferous tubules indicating that there was not a lack of germ cells causing the hypoplasia. Germ cell weakness is obviously a hereditary condition. The sires 545 B, 2 F and 27 U had a relatively low fertility. In their pedigree were several bulls known to have had a low fertility. No sons of 2 F and only a few sons of 27 U were used for A.I. services and at present only few cases of testicular hypoplasia are seen.
authors: Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
authors: I
authors: I
authors: Settergren
authors: K
authors: K
authors: McEntee
mesh_terms: D000818:Animals; D002417:Cattle / Q000002:abnormalities*; D008297:Male; D013094:Spermatozoa / Q000002:abnormalities*; D013737:Testis / Q000002:abnormalities*