Castration in horses

Equine vet Alex discusses castration in horses; where it takes place, how it’s done and what to expect before, during and after the procedure.

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Castration in horses is common, in Scarsdale patients alone we see 2% stallions compared to 98% geldings! Equine vet Alex discusses what’s involved;

When should I castrate my colt?

Castration is usually performed between 6 months and 2 years of age, or later in life for horses used for breeding. The time of castration is decided depending on the horse’s growth, temperament and presence of testicles.
We recommend performing castrations in spring and autumn to avoid the fly season (June-September) and the cold wet weather in winter, when turnout is limited.

Prior to the surgical procedure, the horse must be examined by the veterinary surgeon in order to assess its health status, presence of both testicles and decide the method of castration. Sedation is often administered for a better assessment.
It is recommended that horses are vaccinated against tetanus prior to surgery.

Where can a castration take place?

CastrationThe surgical procedure can take place at the Markeaton practice, or at the horse’s stabling address. For standing castration at the owner’s premises, a clean stable with fresh bedding must be provided.

For smaller breeds, castration under general anaesthesia can be performed at home, only under appropriate weather and environment conditions. A large flat soft surface with no obstacles, good grass cover or enough bedding is required to minimise the risks of accidents at induction and recovery. Prior to general anaesthesia the horse has to be starved overnight and have free access to water. For bigger horse breeds, castration under general anaesthesia is recommended to be performed in the operating theatre at Markeaton due to higher risks of injury associated with recovery from anaesthesia.

How is a colt castrated?

castration in horsesThe castration can be performed under sedation with the horse standing or under general anaesthesia with the horse lying down in lateral recumbency. The most common techniques are the open and the closed castration.

The open castration is usually performed in horses less than 3 years of age. This technique is suitable for standing castration in less temperamental horses with well-developed testicles. Two deep parallel cuts are made through the scrotum and the tunic (testicles supporting tissue) and a cut-and clamp instrument (emasculators) will crush the blood vessels and the spermatic cord, allowing the testicles to be removed. The skin lesions will be left unsutured to allow drainage.
Following this method, post-operative management involves stabling for the first 24 hours to monitor post-surgery complications and turn-out as much as possible after 24 hours to avoid swelling and encourage drainage.

The closed castration is recommended in horses 3 years old and over, donkeys and mules of any age due to bigger size of testicles and blood vessels and risk of post-operative inguinal hernia. This method requires strict aseptic measures and is only performed in the operating theatre at Markeaton, under general anaesthesia. The cut involves only the scrotal skin, leaving the tunic and the testicle intact. One surgical suture will be placed around the blood vessels and spermatic cord and the testicle will be removed together with its protective tissue following application of the emasculators. The lesion in the scrotum is then sutured closed. Following this procedure, the horses will be kept on box rest hand walked for 1-2 weeks and will gradually return to normal work.

The choice of the castration method depends on the horse’s age, breed and temperament, size and position of the testicles.

Prior to castration, one dose of antibiotics and nonsteroidal anti-inflammatory drugs will be administered. Following surgery, a course of oral nonsteroidal anti-inflammatory drugs will be continued for a few days. Depending on the procedure and the associated risks, a course of oral antibiotics might be advised.

Post-castration complications

All the listed complications require veterinary attention;

Lethargy, colic and fever can occur after the surgery due to pain, prolonged time of surgery and post-surgical infections.
Haemorrhage (slow drip) from the scrotum is normal in the first few hours after castration. Continuous fast drip from the lesion has to be reported to the veterinary surgeon.
Swelling of the penis sheath and scrotum is expected in the first few days. If the swelling persists and causes discomfort, the veterinary surgeon has to be contacted.
Herniation of intestine or different anatomical structures from the surgical site represents an emergency and has to be reported to the veterinary surgeon as soon as possible.

Possible cryptorchid (rig)

Cryptorchids are horses that have one or two retained testicles.
The presence of retained testicular tissue can be confirmed by the presence of increased hormone levels in a blood test.
The testicle can be retained in the inguinal canal where they can be palpated under sedation and removed using the afore-mentioned techniques.
If the testicles are retained in the abdomen, laparotomy (abdominal surgery) or laparoscopy has to be performed in order to localise and remove the retained testicle(s). This is a more complex and prolonged surgery with higher risks and extended period of box rest.


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