Equine Castration


  • Castration is usually carried out for ease of management
  • Stallions are often difficult to handle and sometimes dangerous
  • The presence of a stallion may result in unwanted covering of mares


  • Colts may be castrated at any age. Both testicles must have descended prior to castration if the horse is less than a year. If both testicles have not descended by one year of age, this may indicate that the horse is a cryptorchid (a ‘rig’)
  • The traditional time for castration is during the spring of their yearling year
  • There is an opinion that colts should be left later to ensure that they fully mature. However, there is little scientific evidence to support that early castration results in any degree of immaturity so early castration is recommended

The practice is happy to castrate horses throughout the year. Please contact the surgery to discuss your requirements or complete our on-line request form.

My horse only has one testicle?

  • This may indicate that the second testicle has not descended
  • Please ask a vet to examine the horse as sometimes the testicles are difficult to see
  • If greater than one year old, the second testicle is unlikely to descend. In this case, castration is very important. The retained testicle may result in unwanted behaviour later and there is more risk of testicular disease of the retained testicle
  • Your horse may require abdominal surgery in order to locate the retained testicle. This should be carried out at a surgical facility and may be considerably more expensive

We can castrate your colt on your premises. In the case of a retained testicle we will arrange for one of our vets to carry this out at a surgical facility.


  • A competent horse handler, preferably one who doesn’t mind the sight of blood
  • A source of warm, clean water
  • A flat clean area or stable

The procedure

The majority of castrations may be performed in the standing horse under heavy sedation. A light stable or barn is appropriate for this method. In some cases, a short general anaesthetic is required and the horse is castrated lying down. In this situation, a flat grass field would be ideal.

  1. The appropriate anaesthetic is administered
  2. If sedation only is being used, the scrotum is cleaned and local anaesthetic is injected into the scrotum and the scrotal skin.
  3. The scrotum is incised and the first testicle is removed using an instrument to crush the blood vessels. In most situations a second incision is required for removal of the second testicle.
  4. The incisions are not stitched to allow for drainage. This is important to reduce the risk of infection.

We recommend turnout into a small paddock area post castration to allow for some movement to prevent excessive swelling.

Antibiotics and pain relief are administered for a few days post surgery. In addition, it is important that your colt is protected against tetanus. If the primary course of vaccinations is not complete, tetanus antitoxin will be administered at the time of castration for immediate protection against tetanus.


Complications and risks

We see very few complications associated with castration. However, because it is carried out in non-sterile facilities, complications may arise.

These include:

  • Injuries / adverse reaction from sedation or anaesthetic used
  • Post operative bleeding – some bleeding is expected for a few hours. If you can no longer count the drops, then please contact us immediately
  • Post operative infection – some swelling is expected. If this seems excessive or you are worried, please call us. If the horse goes stiff behind, this may also be a sign of infection. He may go off his food and become off colour. PLEASE CALL US ASAP IF THIS OCCURS
  • Herniation. This can be potentially very serious. If you see ANY material protruding from the incision site, please contact us IMMEDIATELY. It may only be a small piece of the sac in which the testes were held but there is potential for this to be very serious if not addressed early