The hereditary 'short tail' sperm defect - A new reproductive problem in Yorkshire boars

This study describes a new sperm defect in Yorkshire boars. The length of t he sperm tail is markedly reduced, resulting in a total immotility in all s permatozoa. At transmission electron microscopy revel, the morphology of th e midpiece microtubular components area is seriously affected. This boar sp erm defect differs from the 'tail stump' defect observed in bulls, the tail s being longer in most spermatozoa than those found in affected bulls. Ther efore, the term 'short tail' sperm defect is more adequate. The authors obs erved the first case in 1987. In 1998, this defect became a noteworthy repr oductive problem, when it was observed in nine boars intended for breeding. In one litter, three littermates were affected with the 'short tail' sperm defect. At the present time the authors believe that the defect is recessi vely inherited.