Cryptorchidism (Retained Testicles) in Horses

August 18, 2008 (published)

Today on the program I am going to talk about cryptorchidism in horses. Cryptorchidism is a condition in which one or both testicles are not in the scrotum. The testicles are either still in the horse's abdomen, which is called an abdominal cryptorchid, or can be in the tissue above the scrotum just outside the abdominal wall, which is called an inguinal cryptorchid. Cryptorchidism is fairly common as one study indicated that one out of every 6 colts that were 2 to 3 years old presented to a veterinary teaching hospital was a cryptorchid. The only treatment for an abdominal cryptorchid is surgical removal of the testicle as it is very unlikely a testicle will leave the abdominal cavity and enter the scrotum after the age of 2 years. Testicle removal is important because even though the testicle will not produce viable sperm, it will produce hormones that will cause the horse to still act like a stud. Some cowboys have castrated horses that are cryptorchids by just removing the one testicle in the scrotum and unethically selling the horse as a gelding.

In the past, the standard surgery to remove a cryptorchid testicle required general anesthesia. However, laparoscopic surgery is being used routinely to remove the retained testicle. In the laparoscopic procedure, instruments are inserted in the horse's flank while the horse is standing. By using a camera, the surgeon can look around in the abdomen, find the testicle and remove it. This is less invasive than making a large incision in the horse's abdomen and is less risky because general anesthesia is not required. If you have a colt that is cryptorchid, ask your vet about laparoscopic castration.

VIN News Service commentaries are opinion pieces presenting insights, personal experiences and/or perspectives on topical issues by members of the veterinary community. To submit a commentary for consideration, email

Information and opinions expressed in letters to the editor are those of the author and are independent of the VIN News Service. Letters may be edited for style. We do not verify their content for accuracy.