Horses - Breeding and Life Stages

Horses can be capable of breeding from 18 months old, but domesticated horses are usually allowed to mature to at least three years old before breeding.  Gestation lasts about 11 months, typically between 320 and 370 days, with an average of 340 days, depending on the breed, and usually results in the birth of just one foal. The foal is capable of standing and running within a short time after birth. 

There is specific terminology used to describe horses depending on their age:

    •    Foal: A horse of either sex less than one year old.

    •    Yearling: A horse of either sex that is between one and two years old.

    •    Colt: A male horse under the age of four. 

    •    Filly: A female horse under the age of four.

    •    Mare: A female horse four years old and older.

    •    Stallion: A non-castrated male horse four years old and older.

    •    Gelding: A castrated male horse of any age. Castration mostly occurs between 6 months and 2 years for temperament and handling reasons.

Regardless of when a horse is born, for horses that enter into racing competitions, a year is added to its age every January 1st in the Northern Hemisphere and every August 1st in the Southern Hemisphere!