High Quality Content by WIKIPEDIA articles! Standardbreds are a breed of horse best known for their ability to race in harness at a trot or pace instead of under saddle at a gallop. Developed in North America, the breed is now recognized worldwide for its harness racing ability. They are solid, well-built horses with good dispositions that are also used under saddle for a variety of equestrian activities, particularly in the Midwest and eastern United States.In the 17th century, the first trotting races were held in the Americas, usually in fields on horses under saddle. However, by the mid-18th century, trotting races were held on official courses, with the horses in harness.