Male horses

thumb|A stallion thumb|A stallion's secondary characteristics include heavier muscling than is seen in mares or geldings, often with muscular development along the crest of the neck. A stallion is an adult male horse that has not been gelded (castrated). Stallions follow the conformation and phenotype of their breed, but within that standard, the presence of hormones such as testosterone may give stallions a thicker, "cresty" neck, as well as a somewhat more muscular physique as compared to female horses, known as mares, and castrated males, called geldings.

right|thumb|A 3-year-old gelding A gelding (/ˈɡɛldɪŋ/) is a castrated male horse or other equine, such as a pony, donkey or a mule. The term is also used with certain other animals and livestock, such as domesticated camels. The equivalent terms for castrated male cattle are steer or bullock, and wether for sheep and goats.

male horse, usually below the age of four years

horse breeding facility in Ireland