Cryptorchidism in Dogs

The testicles in a male dog should normally descend into the scrotum by 2 months of age. In certain dogs, it may occur later, but rarely past 6 months of age. Therefore, any dog 6 months of age or older, that has one or both testicles missing from their final scrotal position, is considered to be cryptorchid. Cryptorchidism affects 1-3% of dogs and can occur in all breeds. Toy breeds such as Pomeranians, Poodles, and Yorkshire Terriers are at a higher risk.

Most cryptorchid dogs (around 75%) will have only one retained testicle. The right testicle is more than twice as likely to be the retained testicle in this case. Retained testicles are located either in the abdomen or in the inguinal canal (groin). Sometimes the cryptorchid testicle can be seen just under the skin in the groin area.

Causes of Cryptorchidism in Dogs

Cryptorchidism appears to have some genetic predisposition because it is seen in the familial lines of dogs. The exact cause, however, is unknown. It is considered to be an X-linked autosomal recessive trait, so a cryptorchid male should not be used for breeding.

Clinical Signs of Cryptorchidism in Dogs

Retained testicles are rarely associated with pain or other clinical signs unless a complication develops. One complication, called spermatic cord torsion, occurs when the testicular cord twists around itself. This presents as sudden severe abdominal pain.

Another possible complication, a Sertoli cell tumor, can develop in a retained testicle and cause the secretion of estrogen. This will result in feminine characteristics in a male dog, such as the development of mammary tissue.

The most severe complication of cryptorchidism is testicular cancer in the retained testicle. This risk is estimated to be at least 10 times greater in dogs with cryptorchidism when compared with normal dogs.

Bilaterally cryptorchid dogs, or dogs with both testicles retained, will usually be sterile because the body temperature in the abdomen is too high to allow for the development of sperm. They will still exhibit male behaviors such as marking and territorial aggression, despite not appearing to have testicles.

Diagnosing Cryptorchidism in Dogs

In cases of inguinal cryptorchidism, the retained testicle can be seen or felt in the inguinal canal. When there is one testicle that has normally descended into the scrotum, and the second testicle cannot be palpated in the inguinal area, the retained testicle is assumed to be abdominal. This can be definitively diagnosed using abdominal ultrasound or radiographs but is rarely required to proceed with surgery. If a dog is exhibiting male behaviors but does not appear to have testicles in the scrotum, a blood test for testosterone can be performed.

Treatment for Cryptorchid Dogs

Surgical removal is the only treatment for cryptorchidism. If the dog is a unilateral cryptorchid, both testicles should still be surgically removed. The retained testicle should be removed to prevent testicular cancer, and the normal testicle should be removed to prevent cryptorchid offspring.

Often, cryptorchid dogs will have 2 incisions following their neuter surgery, one for each testicle. The recovery time can be a bit longer than that for a routine neuter, and your vet will likely recommend 2 weeks of reduced activity, especially if the cryptorchid testicle was in the abdomen.

Prognosis for Cryptorchid Dogs

The prognosis is excellent for cryptorchid dogs who undergo neuter surgery early, before any problems develop. Cryptorchid dogs who have both testicles removed and have no other defects will generally live a normal lifespan for their breed.

Read more:

What You Need to Know About Neutering Your Male Dog

Diseases of the Dog’s Prostate

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