Cryptorchidism

Cryptorchidism is a medical term referring to the incomplete or non-existent descent of one or both testicles in the scrotum.

After birth, testicles descend into the scrotum, because it is colder than the normal body temperature of the animal, and this is necessary for the testicles to function properly. In dogs, both testicles are expected to be in their final scrotal position by 2 months old. It can occur later in some breeds but it rarely happens after 6 months old.

Bilaterally cryptorchidic animals are infertile while unilateral are typically fertile. This abnormality can occur in almost all breeds of dogs, but toy and miniature breeds are at a higher risk. Unilateral is more common than bilateral cryptorchidism and the right testicle fails to descend twice as often as the left one. It is believed cryptorchidism has a genetic factor so removal of affected males from the breeding lines is advised.

This condition is rarely associated with pain or any other sign of disease, but dogs with cryptorchidism have a higher risk of testicular neoplasia than normal dogs (approximately 13.6 times higher). Because of this it is recommended for dogs with this condition to be neutered by the time they have reached four years of age.

Tilley, L. P., & Smith, F. W. K. (2011). Blackwell’s Five-Minute Veterinary Consult: Canine and Feline