Gelding truly is a kindness, offering colts a life with more freedom and less frustration, such as being able to run with their peers.

Gelding Guidelines

Gelding can be done at almost any time and at any age, although the yearling year seems ideal. Be sure that vaccinations are up-to-date before the procedure.  Begin light exercise the day after the surgery to reduce swelling. Plan to keep your colt stress-free for at least two weeks after the procedure. Watch carefully for bleeding and signs of infection. Wait several weeks before turning your gelding out with mares to prevent unwanted pregnancies.

The thought of owning a stallion may be appealing, but there’s a lot to be said in favor of owning a nice gelding. Surgically removing a colt’s testicles is neither inhumane nor unkind—so put aside those pangs of guilt. Castration is generally a trouble-free procedure, and having your colt gelded will allow him to live a freer, more contented life among people and other horses.

A horse can be gelded at any age, and many veterinarians believe “the sooner, the better,” primarily because younger horses have smaller testicles, less risk of heavy bleeding, and often seem to recover more quickly. Early castrations are usually done at 4 to 6 months of age, before weaning. However, there are pros and cons for gelding at various ages and stages of development.

Although there aren’t any good formal studies on this point, many vets believe that when horses are castrated this young, it delays the closure of the growth plates (physes) in their bones. This is a plus if you want a tall, lanky horse, but not if you were planning to start training early.

Colts younger than 4 to 6 months can also be gelded, as long as their testicles have descended into the scrotum and are easy to find. However, anesthesia is riskier in very young foals, so you’ll want to use a vet who is very familiar with drug responses in this age group.

We also don’t know the consequences for growth, development and health. For example, in other species, very early castration tends to result in individuals that are oversized and tend toward easy weight gain. Picture those 30- to 40-pound house cats that result from early castration.

Most horses are castrated in the spring or fall of their yearling year. By this time, the horse has achieved most of his adult height and his growth plates are beginning to close. This is also the time when many colts are showing early fertility and may impregnate a mare—another good reason to geld at this time. While yearlings are young males in terms of fertility, they are still very immature when it comes to aggressive behavior. By removing the influence of male hormones at this point, you’re more likely to get the more docile, laid-back personality associated with most geldings.

By the age of 2 to 3, the horse has reached full sexual maturity. The testicles are now larger and have a well-developed blood supply. Castration can still be done at this, or any later age, but risk of complications is higher. (See sidebar on page 49.) If left intact for too long, there is a greater risk that any undesirable, aggressive behavior toward humans or other horses will not disappear after the castration. When older stallions are gelded, often they will continue to mount mares for one or more years, possibly for life.

Surgical Choices
When a horse is castrated, an incision is made in the scrotum, the testicles are removed, and the spermatic cord and blood vessels are crushed. In an “open” procedure, the incision is not sutured. That way the wound can drain and is left to heal from the inside out. Most castrations are done using the open technique because it’s quicker, less expensive, and can be done on the farm. Open castrations can be done either with the horse standing and heavily sedated, using local anesthesia injected into the surgical site, or with the horse “asleep” under general anesthesia.

In a “closed” procedure, the scrotum is sutured. With a closed castration, which takes longer to perform, the horse is put under general anesthesia so the horse remains perfectly still. Closed castrations are recommended in older horses and horses with large inguinal rings (the opening between the abdomen and the scrotum) because of the higher risk of complications.

The closed technique is also used when gelding a cryptorchid, a condition whereby one or both testicles do not descend into the scrotum. Sometimes the testicles will be all the way inside the abdominal cavity. Locating and extracting the testicles is obviously a more complicated and time-consuming procedure than a regular castration.

Complications of Castraction

Castration is the most common surgery performed in horses, and is usually uneventful. However, there are always risks: Anesthesia. Although rare, it’s always possible for a horse to have an unusual reaction to a sedative or anesthetic. Particularly dangerous are reactions involving the heart, blood pressure, or breathing. These are rare, but they do happen. If the horse is having surgery at a veterinary hospital, all the necessary drugs and equipment to support the horse will be available. Bleeding. Bleeding after castration is the most common complication. It is most likely to occur in older horses with larger testicles and blood vessels. If the bleeding can’t be stopped by keeping the horse quiet or packing the wound with gauze, it will be necessary to anesthetize the horse so that the vet can find the bleeding area and suture the site. There is much less risk of bleeding with closed castrations. Swelling. Some degree of swelling of the scrotum and the sheath is common for the first 24 to 48 hours. It is managed by cold hosing and exercise. Swelling that lasts longer probably indicates infection. Infection. Because most castration sites are left open to heal rather than sutured, infections are fairly common. Your vet will handle this by making sure the surgery site is open so that material can drain freely, and may prescribe antibiotics. Eventration. This is when a section of omentum, the fatty tissue surrounding the intestines, or even a section of intestinal tract itself, falls through the castration site. The testicle and spermatic cord drop into the scrotum through an opening called the inguinal canal, a direct passageway into the abdomen. If the opening is large enough, it can let omentum or bowel out of the abdomen too. While not a common problem, it has been reported in as high as 12% of draft horse colts and is also more common in castration of older horses. Experienced vets will always carefully check to determine the size of the inguinal ring and whether there is any material already coming through it other than the spermatic cord before starting a castration. If there is any question, a closed castration under general anesthesia will be recommended.

Preparation & Aftercare
Castration is major surgery, so be sure your horse is in good health. You should also pick a time when your horse will not be under any particular stress for at least two weeks after the surgery. Vaccinations, especially tetanus, should be up-to-date.

Your vet will need hot water and someone who is capable (and not squeamish) at the horse’s head. Most vets prefer to do castrations in an open, grassy area so that there is less danger of the horse hurting himself if he goes down, or if the vet needs to put him under stronger anesthesia for any reason. Depending on your facility layout, the vet may opt for a stall. Leave this decision to the vet.

Immediately after castration, your horse will still be groggy from the sedative or anesthetic. If the procedure is done at a clinic under general anesthesia, your horse will likely stay overnight. If castration was done at home, your vet will instruct you on how long you should wait to move, feed or water the horse, depending on the types of drugs used.

You will be told to watch carefully for signs of bleeding during the first few hours after surgery. Anesthetics and sedatives lower blood pressure. As these drugs wear off, some slight seepage from the open castration sites is common. If this is a steady drip or stream, though, you need to call the vet immediately. Closed castration sites won’t drip blood, but if there is bleeding inside the closed scrotum, it will start to swell within the first few hours. Again, if there’s any question, call your vet.

Also call your vet immediately if any tissue starts to protrude from the bottom of an open castration. This could be an “eventration,” in which fatty tissue or intestine drops down through the abdomen into the surgical site.

Keep the horse by himself in a small, quiet area for the first 18 to 24 hours. During this time, the horse may seem depressed or subdued. This is understandable considering he’s just had surgery. His appetite and energy levels should recover in a day or two.

After the first 24-48 hours, depending on your veterinarian’s recommendations, the best thing you can do for your horse is to keep him moving. This encourages any fluids in the surgical area to drain and helps eliminate tissue swelling.

In completely uncomplicated cases, swelling is minimal and healing may be virtually complete within 10 to 14 days. Your vet may administer antibiotics to reduce potential infection. But you’ll want to watch for signs of any low-level infection, which causes swelling to persist for longer than usual, and slows healing. Your vet will decide if any special treatment is needed.

Fertility & Behavioral Changes
If your colt is a yearling or older, do not put him in with mares for at least a couple of weeks after he has been castrated. Many people choose to wait three to four weeks to be absolutely sure their new gelding no longer has any viable sperm in his body. Although castration removes the testicles and the sperm they contain, other areas of the reproductive tract are left inside the horse and these still harbor sperm. Studies have found that sperm can be recovered from a horse for as long as three weeks, although after the seven-day mark, the sperm do not move and therefore probably can’t make a mare pregnant. Just to be on the safe side, it’s usually advised that a recently castrated horse not be put with mares for three weeks.

If the horse was castrated for behavioral reasons, don’t expect his personality to change overnight. Once a horse has become aggressive toward people or horses, it may take days, weeks or even years to abate after castration, and the horse may require extensive retraining to change the behavior. Some horses remain aggressive despite castration.

Aggression toward humans usually stops before aggression toward other horses, which is a more complicated social issue than the owner/animal relationship. Sexual behavior will be greatly reduced by castration, but this might not be completely eliminated right away either. If the horse was 2 or older when castrated and already had the muscular crest to his neck and thicker jowls of a stallion, this will become less obvious over time.

Though horses can and should be exercised beginning the day after castration, don’t plan anything strenuous until the surgical area is fully healed. During the healing process, which takes about two weeks, the horse will also completely regain his strength and energy.