Gelding
A gelding is a castrated horse or other equine, such as a donkey or a mule. Castration, and the elimination of hormonally driven behavior associated with a stallion, allows a male horse to be calmer and better-behaved, making the animal quieter, gentler and potentially more suitable as an everyday working animal. As a verb, "gelding" or "to geld" refers to the castration procedure itself.
Etymology
The word comes from the Old Norse geldr ("barren").
History
The Scythians are thought to have been the first people to geld their horses. They valued geldings as war horses because they were quiet, lacked mating urges, were less prone to call out to other horses, were easier to keep in groups, and were less likely to fight with one another.
Reasons for gelding
A male horse is often gelded to make him better-behaved and easier to control. Gelding can also remove lower-quality animals from the gene pool. Ideally, horse breeders choose to leave only their best animals as stallions; lesser specimens are gelded, to improve the overall quality of the breed.