What do you call a horse used for breeding?

A horse used for breeding is typically called a stud (male) or a broodmare (female).

Here are some other terms you might hear:

* Sire: A male horse that has fathered offspring.

* Dam: A female horse that has given birth to offspring.

* Breeding stock: Horses that are kept for the purpose of breeding.

* Stallions: Mature male horses that are used for breeding.

* Fillies: Young female horses that are not yet used for breeding.