Cryptorchidism is a birth defect involving one or both testicles not descending. It is the most common canine birth defect, with occurrences as high as 15 percent in some breeds. Any breed can have affected individuals, but common breeds include Yorkshire terriers, Dachshunds and boxers. Cryptorchid pets have higher risks of testicular problems, including cancer. Most puppies' testicles have fully descended by 8 weeks old, but it can take them several months to descend.
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In mammals, testicles develop in the abdomen near the kidneys. During development, testicles migrate to the scrotum via the gubernaculum. When this process is interrupted or the gubernaculum does not develop correctly, cryptorchidism results. It is generally considered a genetic problem, with an autosomal-recessive gene. Females may carry the gene and produce normal and cryptorchid offspring. Because of this, a study funded by the American Kennel Club's Canine Health Foundation is working to find DNA indicators that may predict occurrence to eliminate breeding in potentially affected dogs.
Affected puppies generally can be diagnosed by a physical exam. Good breeders should check puppies before selling or adopting them out. Veterinarians also palpate the scrotum, which helps identify abnormalities with your puppy. Many puppies are unilateral cryptorchids but some are bilateral. These puppies can be hard to distinguish from castrated males. It is rare for a very young puppy to already be neutered, although some shelters will perform castrations young. In older puppies and dogs, specific blood tests can be used to distinguish a cryptorchid from a castrated dog.
Cryptorchids can be fertile, although bilateral cryptorchids typically are sterile. Increased temperatures in the abdomen versus the scrotum decrease sperm production. More important consequences are the problems related to keeping your puppy intact. Testicles can twist or torse, which is an emergency, and it can occur anywhere from in the scrotum to the abdomen. Intact dogs also can develop testicular cancer, and higher incidences are seen with cryptorchid dogs.
Cryptorchidism can be corrected by neutering your puppy. This is strongly recommended due to the genetic cause, as well as the increased risk of problems. The location of the retained testicle determines how the surgery occurs. Retained testicles in the inguinal region can sometimes come through the same incision as a descended testicle. Abdominal testicles typically are removed like an ovariohysterectomy or spay in a female dog. Your puppy's recovery is similar to recoveries with other surgeries and generally involves two weeks of exercise restriction with no bathing. Always consult an experienced veterinarian regarding the health and treatment of your pet.
By Elizabeth Muirhead
About the Author
Elizabeth Muirhead is a practicing veterinarian with an undergraduate degree in biological sciences. She has real-world experience with the husbandry, grooming, training and feeding a variety of household pets.