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AskHQ: Gelding your yearling

Q: My yearling is being gelded, but this is my first youngster, and I’m unsure of the castration process and the aftercare required. What can I expect?

A: An ‘entire’ male horse’s behaviour is driven largely by testosterone, and this hormone causes ‘entire’ male horses to display herding instincts, sexual interest, and aggression. While typical in a feral herd of horses, this behaviour is much more challenging to manage in the domestic situation, particularly if handlers are not experienced. As a result, castration or ‘gelding’ of colts is common practice.

The procedure

The most common method of castration is permanent, surgical castration. Other methods, such as suppressing testosterone by using drugs, exist but are impractical in most cases. Surgical castration is performed standing, under sedation and with a local anaesthetic. The area is scrubbed, and a surgical incision is made to allow the testicles to be removed using a set of emasculators. These work like clamps and are applied for a few minutes, basically causing the blood supply to the testicles to clot off. The testicles below this point are then removed. The wound is left open to allow drainage from the incision site and usually heals in around a week.


Your colt will need to be kept clean, and you will need to monitor his healing, as it is an open wound, so infection is possible. You need to hose the area with clean, running water, keep his bed clean, and turn him out in a clean pasture. Around 20% of castrations require a vet visit to treat an infection.

Monitoring swelling and bleeding is most important. Swelling is to be expected – the size is dependent on the size of the horse. You should ask your vet for guidance on this. Bleeding is normal initially, but any bleeding that does not stop after a few seconds or where you cannot count the drips needs a call to the vet. Use your vet’s expectations to guide you throughout the aftercare process.


You would expect your horse to be a little easier to manage just three or four weeks after gelding. However, it is worth noting that some behaviours are learned, so – particularly if your horse was castrated late – gelding won’t necessarily remove all behavioural issues.