Castration is one of the most commonly performed equine surgical procedures. Most operations go well and wounds heal uneventfully, with your horse returning to work within a month of the operation. There are various options to consider before your horse has the operation and you will need to speak to your vet to decide what is best for your horse and your situation.

Having a colt or stallion neutered prevents, or decreases, male sexual behaviour. Entire males can often be aggressive but following castration horses will become more docile and manageable. This is as a result of the removal of the primary source of hormones (the testicles) that produces male characteristics. Castration also prevents reproduction. Other reasons for castration include cases of testicular neoplasia (tumour), irreparable traumatic testicular damage, spermatic cord torsion (twisting) and inguinal hernias.

Traditionally castration is undertaken during the spring of the yearling year, but it can be undertaken at any age. Castration in a fully mature stallion is a much more serious proposition and needs careful discussion with your veterinary surgeon before it is undertaken. Management practices usually dictate castration at 6 months to 2 years old before sexual behaviour often commences. Castration is normally carried out in the spring or autumn to avoid the flies and dust of the summer and the mud and wet of the winter. Castration of suckling foals can be very effective and much less traumatic to the individual.

The operation can be carried out at home or at a veterinary surgery with the facilities for undertaking equine procedures. You should consult with your veterinary surgeon regarding where they think the operation should be undertaken, because some veterinary surgeons prefer to castrate horses older than 3 years old at a veterinary practice. Some veterinary surgeons castrate certain types of animal using standing sedation but this is only in specific situations.
If the operation is to be performed at home:

  • Your vet will need some help. There must be a competent handler and ideally somebody to assist your veterinary surgeon.
  • Your horse may be anaesthetised and will therefore need to lie on the ground. You will need to ensure there is a danger-free area where the operation can take place.
  • Ideally the weather should be dry and warm and the environment should be dust and mud-free.
  • You need to supply several buckets of clean warm water and a clean sheet to lay everything on.
  • Conditions need to be as sterile as possible with all the necessary equipment to hand. If you are not sure about the conditions you can provide for the operation at home, speak to your vet who will be able to advise what is best for your horse and your situation.

Before the operation your vet will need to know that your horse is in good condition, and free from any disease. It is essential that your horse has up-to-date vaccinations for tetanus. If this is not the case your vet can administer temporary protection (antiserum) at the time of the operation.
Your horse will need to be fasted prior to surgery if it is to be anaesthetised. Your veterinary surgeon will advise you on the specific regime required.
There are different techniques of castration either undertaken in the standing animal or more usually the recumbent (lying down) anaesthetised horse or pony. Standing castration involves deep sedation and a local anaesthetic in to the testicles and scrotum. This method is slightly less expensive and avoids the risks of a general anaesthesia. This method is often used for yearling or two-year old Thoroughbred colts which are well handled.
Some veterinary surgeons prefer to avoid carrying out castrations in smaller horses, or if they are older than three years of age, and may prefer to carry out a standing castration at their practice premises. There are risks to the handler and veterinary surgeon with this method. The recumbent method involves a general anaesthesia and its attendant risks. Your horse will be laid in lateral recumbency (on his side) with his upper back leg pulled forward and ideally secured with a rope.
Castration involves the removal of both testicles through open incisions in the scrotum. There are three different techniques:

The ‘open’ technique

Once the testicles have been removed, the wound is left open to allow for drainage and minimise swelling after the operation – this operation usually only takes about 10 minutes.

The ‘closed’ technique

The testicles are removed and the cord that supplies the testicles with blood is ligated with suture material. The various layers of the scrotum are sutured (sewn) together. This technique decreases the incidence of bleeding post castration and herniation of the intestines through the wound, as well as other post-operative complications – this operation usually takes about 20 minutes.

The ‘modified open’ technique

Similar to the ‘open’ technique, but involves more dissection time, therefore the operation usually takes about 20 minutes.

As with any operation, especially ones involving general anaesthesia, there are risks. To help avoid any complications during anaesthesia your horse will be given a pre-anaesthetic check. Your horse’s physical status will be checked (temperature, pulse, respiration, etc) along with any current medication he is on, and his general attitude and behaviour noted. It is important to realise that although the incidence of anaesthetic deaths is low in healthy individuals it can occur for apparently no reason.
Other risks include haemorrhage from the surgery site, herniation/evisceration of intestines through the wound, swelling around the surgery site, infection and peritonitis. Most of these are fairly uncommon, however swelling is normal after castration and is usually obvious for 3-5 days after the operation. If you notice that the swelling lasts longer or gets worse, you should call your vet for advice. If you notice any other abnormal signs or if your horse seems ‘under the weather’ be sure to call your vet for advice.

After the operation the horse is usually stabled for 24 hours to allow the horse to recover and the surgical site to settle down. The animal should be monitored regularly during this time for complications. If the horse or pony has been castrated in a veterinary hospital they will inform you when they feel it is safe to discharge the animal. Usually 24-48 hours post-operatively.
Once your horse is back at home you will need to exercise him regularly with some periods of trotting and in-hand walking each day for up to 14 days after the operation. This will help to reduce any swelling and help the healing process. If your horse is stabled make sure his bed is clean and deep, a straw bed is ideal as this will not stick to the wound like other materials; if your horse is turned out the paddock should be grassy and free of mud and dust.
The wound can take up to 3 weeks to heal if an open technique is used (there will be discharge from the wound for the first 10-14 days). With the closed method there is no wound discharge and it heals in 12-14 days. Most castration wounds heal uneventfully and your horse should be able to return to work within the month.