Horses are usually castrated at the age of 2 years. Preferably, this is done in spring or autumn so that horses do not have to endure so many flies. In winter it is often too cold to perform a complete anaesthetic on a horse as it will get in a hypothermic state too fast. It is also best when a horse can move a lot after castration because by standing still the castration wound and the shaft of the horse swell too much.

With modern anaesthetics at our disposal nowadays it is not necessary any more to castrate a horse while standing. Although this is still possible, it results more painful for the horse than a full anaesthetic.