Monto Veterinary Surgery

Equine Castration

Becoming educated on the entire process of castrating horses will help you make decisions that are best for your horse. Castration has been used to control masculine/aggressive behavior in the male horse for hundreds of year and is often also referred to as: gelding, cutting, or emasculating. 

Although equine castration is commonly performed by the Veterinarians in our practice, it should never be considered routine, as the procedure can have very serious complications. Furthermore, the follow-up care is extremely important. In this article below, we'll see how castration is performed in the horse, when it can be performed, potential complications, and the myths behind castration in horses.

Why Castration? 
Castration in any species involves the removal of one or both testicles and associated structures (such as the epididymis) and part of the spermatic cord. Removal of both testicles usually rids the horse of unwanted stallion-like behavior, including screaming at and fighting with other horses, attempting to mount other horses, erection and potentially aggressive behavior toward humans. However, when castration is performed at a late age and/or after the horse has been used to breed mares, is not always successful in abolishing learned stallion-like behavior. Even though the horse will not be able to reproduce, the behavior of mounting mares in the pasture in an attempt to breed and aggressive behavior with other horses might not cease. 

When To Castrate? 
Horses can be castrated at any age, but at MVS, we advise that castration of horses at a young age (less than one year old) is ideal. Male horses at that age have smaller testicles that are easier to remove and have less of a chance of severe bleeding post-operatively. The ideal time to castrate a horse is variable and will depend on several factors, including the management of your farm, the climate, training schedules, and so on. 

The most basic requirement for a normal castration is that the horse has two testicles descended into the scrotum. This must be confirmed before surgery is begun! If one or both testicles are "missing" then the horse is considered a cryptorchid and it requires more extensive surgery than a routine castration.

Although castration is one of the most common surgical procedures performed in the horse, it also has several complications, some of them quite serious. The most common complications are swelling at the incision sites or in the prepuce (sheath), and post-operative bleeding. It is normal for an occasional small amount of blood to drip from the incision sites; however, a steady drip or stream of blood is too much. If bleeding persists after surgery, then the incision must be packed with gauze to apply pressure and stop the bleeding. In cases of severe bleeding, the horse usually is anesthetized again and the offending blood vessel is ligated (tied) to prevent further hemorrhage. 

It is normal and expected for a certain amount of swelling to be present at the castration site. However, severe swelling usually indicates a problem, usually infection. 

Follow-Up Care 
Care after the surgery is extremely important, especially if the skin incisions are left open to heal on their own. The horse should rest quietly in his stall for 24 hours following castration. After that time, however, it is imperative that he has exercise for at least one hour every day. Frequently, people make the mistake of turning the horse out in a paddock or pasture. Many times the horse, especially if he is a little sore, will just stand quietly and graze. Castrated horses need exercise to keep their incisions draining appropriately. Therefore, they need to be lunged or chased! 

If they are not exercised appropriately, then the skin incisions can close prematurely, and the area can become very swollen, painful, and infected. Daily cold water hosing also helps keep the swelling down and will help clean the incisions. 


The "Proud-Cut" Myth 
Geldings which continue to mount mares or those which have continued aggressive behavior following castration are often referred to as being "proud cut." This term has been used to imply that the castration was not completely performed, and that a portion of a testicle or epididymis was left in the horse and is still producing hormones that cause stallion-like behavior. If a portion of the epididymis was left in the horse, it would not cause the horse to continually act like a stallion as the epididymis cannot produce testosterone on its own. 

If you have a "gelding" which acts like a stallion, there are two possibilities.

Problem 1: The horse might have a cryptorchid testicle that is retained high in the flank or in the abdomen that still is producing testosterone and creating the stallion-like behavior. The testicle was not found during a normal castration, and the entire testicle or a major portion of it was left in the horse.

Solution: Your veterinarian can take blood samples to determine if your horse is producing testosterone at similar levels to a stallion. A baseline blood sample is taken, then a hormone (hCG--human chorionic gonadotropin) is administered and will stimulate testosterone production if the horse has functional testicular tissue in his body. This is one of the best ways to determine if a horse has a cryptorchid testicle hidden somewhere. 

Problem 2: Your horse is a true gelding with no testosterone-producing tissue in his body (i.e., no testicular tissue) and still displays stallion-like behavior, possibly due to learned behavior. On the other hand, in one study in which male horses' behavior was evaluated following castration, there was no significant difference in behavior whether the horses were castrated at less than two years of age or at more than three years of age. Regardless of the age at which they were castrated, up to 30% of the horses still displayed stallion-like behavior, including aggression toward other horses. The study noted that 5% of the horses displayed aggression toward humans.

Solution: Most veterinarians believe that in true geldings, appropriate training can reduce or eliminate the stallion-like behavior. Luckily, most castrations in horses are performed with no complications, and a healthy, well-adjusted gelding is the end result.