Larry Catt, D.V.M.
Larry G. Martin, D.V.M.

24 Hour Emergency
El Cajon (619) 590-1991
Ramona (760) 789-6845


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A cryptorchid or “ridgling” is a male horse with one or both testicles retained in the abdomen. Normally the testicles have descended from the abdomen into the scrotum by the time a colt is born. In cryptorchids, the testicle(s) do not descend from the abdomen, or they only partially descend, lodging in the inguinal canal between the abdomen and the scrotum.

Cryptorchids demonstrate stallion-like behavior, though externally no testicles are apparent. The condition is typically first recognized when a colt is presented for castration.

The term “proud cut” describes any apparent gelding that acts “studdish”. “Studdish” behavior includes raising the ears, head and legs in a characteristic gait when around other horses, teasing of mares, and sometimes actual penile penetration of mares.

Proud-cut geldings may have had a small amount of testicular tissue left in the scrotum after the gelding procedure. This tissue continues to produce testosterone, which accounts for the “studdish” behavior. However, many geldings that have been properly castrated (gelded) show stallion-like behavior. Training and avoidance are the best ways of dealing with this behavior.

Hormone evaluations are of great use for determining if a horse is in fact a gelding, cryptorchid (having one or both testicles retained in the abdominal cavity), or a complete stallion. In addition, these hormone assays are helpful in the diagnosis of hermaphrodites. These are horses possessing sexual genitalia of both the mare and stallion.

If you have a horse that is exhibiting stallion like behavior without having a testicle present in the scrotum, it is wise to have a blood test performed. The blood is sent to a lab which determines the levels of testosterone and estrone sulfate. From the values that your horse has, the lab can determine if your horse is a gelding with non-hormone related behavior, a stallion or a cryptorchid. Following the blood test result you can make an educated decision on what method of treatment you want to pursue.

Normal levels of Estrone sulfate and Testosterone:

  Testosterone Estrone sulfate
Stallion 1.0 – 4.0 ng/ml > 15,000 pg/ml
Cryptorchid —— > 4,500 pg/ml
Gelding < .25 ng/ml < 1,200 pg/ml

Cryptorchids can be surgically corrected. The surgery is much more extensive than a routine castration because it involves locating the testicles in either the inguinal rings or in the abdominal cavity.

Please call the office if you have any questions regarding Cryptorchidism.