Owners of cryptorchid dogs are often unaware of their dog’s retained testicles until they take their puppy to a veterinarian for a wellness examination and puppy vaccination series. Most veterinarians normally check male puppies to see if both testicles are in their proper anatomical location. This is detectable by manual palpation. Usually, both testicles are completely descended into the scrotum by 8 to 10 weeks of age. However, in some dogs the process takes longer. If one or both testicles are retained by the time the puppy reaches 6 months of age, he is considered to be a cryptorchid and in most cases should be neutered.
Several laboratory tests are available to help a veterinarian determine whether a supposedly neutered male dog has in fact been fully castrated, or whether he has a retained testicle or testicles. An appropriate dosage of a substance called human chorionic gonadotropin (hCG) can be injected intravenously or intramuscularly, with blood samples being taken several hours before and after hGC administration. Another substance, called gonadotropin-releasing hormone (GnRH), can also be used, in lieu of hCG. Both of these normally stimulate the release of testosterone into circulation in intact male dogs, including those dogs with retained functional testicles. However, if a dog has been properly neutered, his blood testosterone levels will be low and will remain unchanged before and after administration of hCG or GnRH.
Another very useful diagnostic tool is transabdominal ultrasound, which can identify the precise location of undescended testicles, whether they are retained in the abdomen or in the inguinal canal. Abdominal ultrasound is completely painless and non-invasive. Normally, it requires no sedation and is well-tolerated by the patient.
Males with retained testicles should not be used for breeding and cannot be shown in the American Kennel Club conformation ring. If you are buying a male puppy as a potential show dog, it is quite important to be sure that both of his testicles have properly descended by the time you acquire him, to avoid future disappointment and economic loss.