Evaluating Infertility in the Stud dog

A thorough exam should include a comprehensive review of past breeding performance, as well as a family history looking for predisposing hereditary causes. Other factors to consider are recent illnesses, medications, vaccinations, and diet.

Collecting and evaluating semen is a most important part of the infertility exam. The number of sperm per milliliter and the quality of the semen are the two most important considerations. When the sperm count is low (a condition called oligospermia), there may be a problem with the epididymis or testicles. The complete absence of sperm (azospermia) suggests severe testicular degeneration, a blockage in the spermatic ducts, testicular tumor, testicular hypoplasia, or retrograde ejaculation. In a dog with retrograde ejaculation, sperm will be found in urine collected from the bladder shortly after ejaculation. The semen and prostatic fluid are cultured to rule out infection.

Baseline laboratory tests screen for chronic diseases. Measuring the sex and thyroid hormones (testosterone, FSH, LH, and a complete thyroid panel) provides information on possible endocrine causes of infertility. Testicular biopsy gives information on causes of low sperm count, as well as the likelihood the dog will respond to medical treatment.