Cryptorchid Confusion

Q. I recently went to look at a horse that I was interested in buying. The man selling the horse told me that when the horse was gelded only one testicle had dropped. A friend who came with me to look at the horse told me to walk away because he was "proud cut" and could potentially become a danger to my other gelding. After doing research about the term “proud cut,” I found the horse is actually a cryptorchid. I really like the horse—should I not consider buying him?

Ashleigh, via email

A. A cryptorchid is where one or both testicles have not fully descended into the horse’s scrotum. This retained testicle can be located just above the scrotum in the inguinal ring or in the abdomen.

The retained testicle is unable to produce spermatozoa due to the increased surrounding temperature (versus the cooler temperature surrounding a descended testicle) but is still hormonally active. The main hormone produced by the testicle is testosterone, which causes stallionlike behavior (for example, increased vocalization around mares, mounting of mares, aggressive behavior toward other horses, etc.) to be exhibited. This behavior often starts when the horse becomes sexually mature, around 2 to 3 years of age. Often this behavior is unacceptable to the majority of owners.

Fortunately you found out this horse is a cryptorchid before purchasing him; the vast majority of owners only find out that their newly purchased gelding is a cryptorchid with a retained testicle after having him home and witnessing stallionlike behavior.

Fortunately a cryptorchid can be fixed with no long-term behavioral issues. Depending on the location of the testicle, there are several surgical techniques that veterinarians can utilize to remove the testicle. Once the retained testicle is removed, testosterone values fall to that of a gelding within a few days.

If you think this is the horse for you I would not let the fact that he is a cryptorchid keep you from buying him. Just realize that he could have some unacceptable behavioral issues in the future that will require surgery to fix. Typically the surgery will only keep a horse out of performance for a few weeks or months, depending on the specific surgery performed.

About the Author

Ryan Ferris, DVM, MS, Dipl. ACT

Ryan Ferris, DVM, MS, Dipl. ACT, graduated from veterinary school at Washington State University in 2007. He then completed an internship in equine surgery, medicine and reproduction at the Equine Medical Center of Ocala in 2008. He subsequently completed a two-year equine theriogenology residency program at Colorado State University (CSU). Ferris joined the CSU faculty as a clinical instructor in the department of clinical sciences in 2010. He is primarily is involved in the clinical broodmare, foaling, and embryo transfer programs at the Equine Reproduction Laboratory. He also consults on reproduction cases and emergencies at the CSU James L. Voss Veterinary Teaching Hospital.

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