The problem stud dog.

When presented with a dog for infertility examination, a complete history, physical examination, and semen evaluation should be completed. Abnormalities of the spermiogram should be documented and differential diagnoses determined. Potential causes of infertility include prostatic, testicular, epididymal, scrotal, vascular, neoplastic, traumatic, infectious, endocrine and autoimmune diseases. Failure to breed and ejaculatory disorders may also play a role. This article reviews the diagnostic work-up, differentials, and treatments for infertility in stud dogs.