Horse breeding and studs

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.

thumb|A broodmare. Note slight distension of belly, indicating either early pregnancy or recent foaling.

thumb|A foal at about weaning age

human-directed process of selective horse breeding

official list of animals belonging to a certain species, subspecies or lineage

horse disease

horse breed