Stallion

A stallion is an uncastrated adult male horse that is capable of breeding. A male horse is called a colt before reaching maturity; once mature and not castrated, the animal is a stallion. A castrated male is a gelding. The term stud is often used for a stallion kept primarily for breeding or for sires used in breeding programs.

Stallions reach sexual maturity around two to three years, depending on breed and individual. Before breeding, many stallions undergo a breeding soundness examination to assess health, conformation, and fertility, including semen analysis. Mares have an estrous cycle, and stallions may show interest, guard mares, display mounting behavior, and vocalize. Fertility depends on health, nutrition, handling, and absence of disease. In breeding contexts, management aims to balance fertility with safety for mare and handler.

Management and welfare: Stallions can be more challenging to manage than geldings or mares due to territorial and mating behaviors. They typically require experienced handling, secure fencing, and careful exposure to mares. In practice, breeding stallions may be housed separately or under supervision around mares, and training emphasizes obedience, desensitization, and safety. Ethical considerations include responsible breeding, avoiding inbreeding, and ensuring veterinary care and welfare.