Aplasia of the ductuli efferentes--a new sterilizing congenital syndrome in the bull.

A young bull of Holstein-Friesian breed showed constant aspermia and increasing swelling of both testes. The histo-pathological examination of the testis-epididymis after slaughter gave the explanation that the aspermia was due to lack of connection between rete testis and ductus epididymidis, i.e. aplasia of the ductuli efferentes. The characteristic ductuli efferentes epithelium was only found in a group of rudimentary ducts, collapsed and empty, situated in the right caput epididymidis. In rete testis an accumulation of loose sperm heads and a strong spermiophagic reaction were seen both in the epithelium and in the interstitia, characterized by abundant occurrence of giant cells and plasma cells. The case reported here necessitates that this new type of aplasia in the future should be regarded as a specific syndrome: aplasia of the ductuli efferentes, in contrast to segmental aplasia of the Wolffian duct (Blom & Christensen 1951).