Dehorning is the process of removing the horns of livestock. Cattle, sheep, and goats are sometimes dehorned for economic and safety reasons. Disbudding is a different process with similar results; it cauterizes and thus destroys horn buds before they have grown into horns. Disbudding is commonly performed early in an animal's life, as are other procedures such as docking and castration. In some cases, it can be unnecessary.

Many breeds of cattle and sheep are naturally hornless. The polled gene can occur naturally in particular breeds or easily manipulated during breeding to lack horns, therefore do not need to be dehorned or disbudded. Although polling is common among cattle and sheep, a variety of livestock species cannot easily be bred to lack horns naturally. In one case, the poll gene in goats was linked to hermaphrodism in a single study several decades ago, although fertile polled goats have been bred.

Horns are removed because they can pose a risk to humans, other animals and to the bearers of the horns themselves (horns are sometimes caught in fences or prevent feeding). Dehorning is only recommended with local anesthesia and sedation by a veterinarian or a trained professional, although a 2011 study showed that only 10% of dairy farmers follow guidelines. Removal of larger horns is usually performed during spring and autumn to avoid fly season. In very large horns, "tipping" (removal of the tip of the horn) may be recommended to minimize bleeding. Dehorning is not routinely performed, since it is a difficult and painful process for the animal. Instead, most breeders disbud their animals while young, when the process is quick and easy. Dehorning is controversial because of the pain it causes.