When a male puppy is in the womb its testicles are drawn up inside the body. After birth the testicles begin a journey from inside the tummy (abdomen) to the scrotum. Both testicles should have descended to the scrotum by six month of age and be easy to palpate. If testicles do not end up in the scrotum by this age they are said to be ‘retained’. Retained testicles are a relatively common occurrence in male puppies, particularly in certain breeds. If your puppy has retained testicles we will probably recommend an operation to remove them (castration).

In most cases cryptorchidism is caused by a defective gene. In order to cause this condition the gene is usually present in both the mother and the father. Since the defective gene may be passed on to future generations animals that are cryptorchid should not be allowed to breed. Breeding should also be avoided from the mother and father of affected animals.
To avoid future complications dogs with retained testicles should be castrated. Removing retained testicles can be a difficult operation as they may be located anywhere in the abdominal cavity. Sometimes the internal testicle can be detected – usually by ultrasound but often it is too small to be seen clearly. In any case your vet will need to open up your dog’s belly to remove the missing testicles. This should be done before the dog reaches middle-age to reduce the risk of the retained testicle becoming cancerous.
Since the animal is not suitable for breeding (due to the high risk of passing on the condition) both testicles should be removed – even if one is in the scrotum. This is important to prevent possible future confusion. If the puppy is rehomed and only one testicle is found in the scrotum further surgery might be carried out to try to locate the (already removed) other testicle.