A male puppy's testicles usually descend from his abdomen into his scrotum by the time he's 10 days old. If one or both haven't dropped by the age of 4 months, it's unlikely to happen. That makes your dog a cryptorchid. Because cryptorchidism carries serious health risks, he'll require surgery to remove the retained testicle as well as the one that fell.
A dog might be unilaterally cryptorchid, with only one testicle descending, or bilaterally cryptorchid, whereby neither drops. In unilateral cryptorchids, the right testicle is far less likely to drop than the left one. Occasionally, dogs are born as monorchids, meaning only one testicle developed. That diagnosis generally occurs after a vet performs surgery to remove the undescended testicle and can't find it. It's possible that testicles don't descend in some canines because of insufficient testosterone production, according to the website Pet Informed.
Any male canine, purebred or mixed, can experience retained testicles. However, certain breeds appear genetically predisposed to cryptorchidism. These include the Chihuahua, the Maltese, the Pekingese, the Pomeranian, the German shepherd, the miniature and the toy poodle, the Yorkshire terrier, the Old English sheepdog, the dachshund, the boxer, the bulldog, the Shetland sheepdog, the American Staffordshire terrier, the cairn terrier, the miniature schnauzer and the Siberian husky. Dogs with retained testicles can't show in conformation classes, as it is a defect; they should not be bred.
Dogs with retained testicles have a risk of testicular cancer that's 10 times greater than that for an intact dog with both testes. Often, a cancer known as a Sertoli cell tumor forms, causing a feminizing appearance in male dogs. They're also vulnerable to testicular torsion, or twisting of the testicle. Attached to the vas deferens, a testicular cord, the twisting retained testicle cuts off the blood supply provided by the cord. Untreated, this painful condition can cause potentially fatal peritonitis as the testicle dies within the body.
It's not enough to conventionally neuter a dog with one descended testicle and leave the undescended testicle alone. Because of the risk factors, and the fact that the dog will still exhibit the male dog's desire to breed without the ability to do so, the retained testicle requires surgical extraction. Before surgery, your vet locates the undescended testicle via ultrasound. The testicle could be just above the scrotum -- never quite making it into the sac -- inside the inguinal canal or still in the abdominal cavity. The vet might need to do some exploratory surgery if the testicle's location wasn't clear on the ultrasound.
Because the dog has to undergo abdominal surgery, he will take longer to recover than from a traditional neuter surgery. Recuperation more resembles that of the spayed female dog. Keep him quiet for at least two weeks after the operation while his body heals. He'll probably have to wear the "cone of shame," or Elizabethan collar, to prevent him from chewing at the sutures.