The Thoroughbred is a popular horse breed widely recognized for its speed and athleticism. Bred specifically for horse racing since the 17th century, Thoroughbreds continue to rule racetracks around the world.

While the racing industry produces tens of thousands of Thoroughbreds each year, most of these horses move on to second careers after they retire from the track at young ages.

Fortunately, many of the characteristics that make this breed ideal for racing also translate to success in various equestrian sports. However, off-track Thoroughbreds (OTTBs) often have unique training, health, and nutrition needs.

This article will discuss the history, breed characteristics, common health problems, and nutrition requirements of Thoroughbred horses. Keep reading to learn more about caring for and feeding your Thoroughbred.

Thoroughbred History

While horse racing dates back to ancient times, the history of the Thoroughbred breed began just over 300 years ago with three foundation stallions. Since then, selective breeding for speed and endurance has continued to improve the Thoroughbred we know today.


The modern Thoroughbred can trace its ancestry to three stallions imported to England from the Middle East in the late 1600s and early 1700s. These foundation stallions included the Godolphin Arabian, the Darley Arabian, and the Byerley Turk. [1]

Breeders crossed these stallions with English mares to produce offspring that could maintain high speeds over long distances. The term “thro-bred” first emerged in 1713 to describe the resulting cross. [1]

Genetic studies show that most Thoroughbreds alive today descend from just 27 stallions from the 18th and 19th centuries. Over 95% of paternal lineages trace back to the stallion Eclipse, a great-great-grandson of the Darley Arabian. [2]

The first breed registry for Thoroughbred horses emerged with the original volume of the General Stud Book, published by James Weatherby in 1791. The studbook collected and documented the pedigrees of racehorses descended from these bloodlines in Great Britain.

Historic Use

Records indicate flat racing existed in England as early as the year 1174, but the first formal publication devoted to racing, the Racing Calendar, wasn’t founded until 1727. The launch of this publication corresponds with the rising popularity of Thoroughbred bloodlines at racetracks. [3]

The sport gained royal support in Britain under the reign of Charles II, an avid horse racing enthusiast, in the 17th century. [4]

In the early 18th century, Thoroughbred racing concentrated on longer races of up to 4 miles and multiple heats. Race distances changed by the end of the century with the establishment of the English classic races, ranging from 1 mile to 1.75 miles. [1]

The change in race distance led to a shift in breeding practices, emphasizing horses with greater speed that could race at younger ages. Thoroughbred bloodlines in England during this time were also developed for steeplechasing. [1]

American settlers soon brought the sport to the colonies. Bulle Rock, the first Thoroughbred in the American Colonies, crossed the Atlantic in 1730. In the early 19th century, match races popularized Thoroughbred racing in the United States. [5]

In addition to their role in the racing industry, Thoroughbreds were also used to improve other breeds in the U.S. The imported stallion Messenger served as the foundation sire of the Standardbred, and Thoroughbred blood was critical for the development of the American Quarter Horse.

Breed Registry

The Jockey Club is the North American breed registry for Thoroughbred horses. This registry maintains the American Stud Book, which records every Thoroughbred imported to or born in the United States, Canada, and Puerto Rico.

First published in 1873, the American Stud Book is the North American version of Britain’s General Stud Book. The Jockey Club was incorporated in 1894 to establish a governing body dedicated to improving Thoroughbred breeding and racing in North America.

Today, the club’s database contains ped