Owners of cryptorchid cats are often unaware that their companion has one or two retained testicles. The condition is usually discovered during the kitty’s initial visit to a veterinarian for a wellness examination and kitten vaccination series. Most veterinarians will check to see if both of a male kitten’s testicles have descended into their proper anatomical location. This can be detected by manual palpation. Usually, both testicles are completely descended into the scrotum by about 6 to 8 weeks of age. Occasionally, the process takes a bit longer. If one or both testicles are not descended by the time the kitten reaches 6 months of age, he will be considered to be a cryptorchid. It is uncommon for both testicles to be retained in a cryptorchid cat; usually, one descends normally and one doesn’t.
Manual palpation is usually sufficient to identify whether a cat’s testicles have descended normally. Sometimes, a male cat is neutered but still has a retained testicle in his abdomen or inguinal canal and may still be fertile. Several laboratory tests are available to help a veterinarian determine whether a supposedly neutered male has in fact been fully castrated, or whether he has a retained testicle or testicles. A substance called human chorionic gonadotropin (hCG) can be injected into the cat’s veins (intravenously) or muscles (intramuscularly). Blood samples will be taken several hours before and after the hGC is administered. If the cat has one or two retained functional testicles, his circulating testosterone levels will go up after he is given hGC. Another substance, called gonadotropin-releasing hormone (GnRH), can also be used, instead of hCG. Both of these substances are normally produced in cats. They stimulate the release of testosterone into the bloodstream of intact males, including those thought to be properly neutered that still have one or two retained functional testicles. If a male cat has been successfully neutered, his blood testosterone levels will not change after administration of either hCG or GnRH. If he has a retained testicle, his blood testosterone levels will go up.
Another useful diagnostic tool is transabdominal ultrasound, which can identify the precise location of undescended testicles in male cats, whether they are retained in the abdomen or in the inguinal canal. Abdominal ultrasound is completely painless and non-invasive. Normally, it doesn’t require any sedation and is tolerated extremely well by the patient.
Most authorities recommend that male cats with retained testicles should not be used for breeding and should not be shown. Cryptorchid cats should be neutered so that they don’t pass on this hereditary condition.