Review of the procedure

Castration or “gelding” is one of the most commonly performed surgeries in horses and most owners consider it to be a routine procedure. However, it has an overall reported complication rate of about 10%. Most of these are minor but occasionally some serious problems can occur.

When it is done and why

A gelding operation involves the surgical removal of the testicles, as horses, (unlike cattle) are not suitable candidates for the crushing of the spermatic cord. The aim is to produce a male horse that is quieter and easier to manage than a stallion. It is most commonly carried out when the colt is a yearling and at a time of the year when flies are unlikely to be a problem.

Surgical overview

Castration under a full general anaesthetic (which causes the horse to lie down) facilitates a more sterile technique. It also allows the blood vessels to be tied off as well as crushed during the operation, thereby reducing the risk of heavy bleeding afterwards. However, every general anaesthetic also carries a risk of death or injury during recovery for the horse so traditionally in the UK and Ireland, the majority of castrations are performed on a standing and sedated horse.

During a routine standing castration, the veterinary surgeon will first sedate the horse before cleaning the scrotal skin and injecting local anaesthetic. Further cleaning is carried out while the anaesthetic is allowed time to take effect. The skin over the testicle is cut to allow it to be lifted out of the incision. An instrument called an emasculators (Fig 1) is placed around the spermatic cord (which contains the testicular blood vessels). As it is closed, it both cuts and crushes the blood vessels. The emasculators is left in place for several minutes to reduce the risk of bleeding. The procedure is then repeated on the second side.

The skin incisions are left open to drain and will heal up within 10-14 days. Some swelling at the site is normal after the surgery and this should start to reduce within three to four days. Gentle cold hosing of the incisions is helpful to reduce the swelling and keep the area clean. If the horse is not turned out, he should be walked twice daily to help the swelling to resolve.

Possible complications

As mentioned above, some swelling is to be expected. However if the swelling is severe enough to result in the horse walking stiffly or becoming reluctant to move/urinate, then further treatment by your veterinary surgeon is needed.

Infection is also a risk and is associated with swelling and pus collecting at the skin incisions. The horse may have an increased temperature (over 38.5C) and be dull and listless or off his feed. Your veterinary surgeon will need to prescribe antibiotics and may also drain any abscesses present. In most cases the infection resolves once it is treated but occasionally a “scirrhous cord” may occur. This refers to a chronic infection associated with a particular type of bacteria known as a staphylococcus. Surgery may be needed to cut away all the infected tissue.

Excessive bleeding can occur after castration. It is normal for blood to drip from the site for up to an hour after the procedure. These drips typically will be slow enough that you can count the individual drops. However if the testicular artery starts to bleed, this will result in a steady flow from the wound and severe blood loss may occur. If this happens the horse needs immediate veterinary attention. The horse should therefore be monitored for several hours after the surgery so that any heavy bleeding can be dealt with immediately. For this reason it is recommended that the surgery is performed in the morning and the horse kept in a clean stable where he can be checked every hour or so for the rest of the day. If all is well, the following morning the horse can then be turned out in a clean paddock for a week or two to continue his recovery (with no access to mares!).

Removal of the testicle also creates a potential link between the skin incision and the horse’s abdominal cavity via a natural opening called the inguinal canal. Occasionally some of the intestinal contents may slip down through this into the incision and a flap of tissue (omentum) or, worse still, a length of intestine may appear from the wound and the horse will start to colic. This is called evisceration (Fig 2) and is more common if the horse had an inguinal hernia (swelling of the scrotum) as a foal.

If evisceration occurs, you should call your veterinary surgeon immediately, as fatal peritonitis or damage to the intestines may occur. In the meantime place a clean, damp towel or sheet under the incision and tie it over the horse’s back to prevent the intestines reaching the floor and being walked on. Keep him as calm and quiet as possible until the veterinary surgeon arrives. A flap of omentum can normally be trimmed away by your veterinary surgeon but if the intestines are involved, surgery may be needed to clean and replace them in the abdomen. If the horse is known to have had an inguinal hernia as a foal, he should be castrated under general anaesthesia so that the inguinal canal can be tied off.

How to work with your vet to reduce the risk of complications

Ensuring that the colt is well handled makes gelding him a lot safer. If he is hard to handle, a lot more sedatives are necessary and they do not work nearly as well as in a calm animal. If he is restless during the surger,y there is a much greater chance of tissue damage and infection. You also need to be able to handle the horse to cold hose or exercise him and administer any painkillers or antibiotics prescribed by your veterinary surgeon for follow up treatment.

Cleanliness greatly reduces infection. The surgery should be performed in a spotlessly clean and well-lit stable on a clean and dry horse (especially the tail hairs and belly). A plentiful supply of clean hot water should be available and a clean straw bed is a suitable bedding material. Shavings are best avoided, as they tend to stick to the wound.

If you are short of help or suitable facilities, let your veterinary surgeon know in advance so that alternatives can be arranged. For example it may be easier to bring the horse to the veterinary practice and have the castration performed as a day surgery. Whilst gelding is a common procedure, it is not a minor one, and so some advance planning with your veterinary surgeon can go a long way towards a straightforward surgery and uneventful recovery for your horse.

Karen Dunne MVB MA, CertEm (Stud Med) is a vet and veterinary nursing programme director at Dundalk Institute of Technology. She’s a member of Veterinary Ireland Equine Group.

E-mail: hq@vetireland.ie

Telephone: 01-4577976