The knobbed acrosome defect in four closely related dogs.

The knobbed acrosome defect (KAD) has only once been reported in dog sperm. This report describes the breeding history, clinical presentation and semen evaluation of four closely related miniature Schnauzer dogs that had between 8 and 44% sperm with KAD. Two of the dogs had no substantial reproductive or sperm defects other than the KAD and were of normal fertility.