The American Quarter Horse is the most popular horse breed in the world. The AQHA has registered more than 6 million Quarter horses since 1940, thanks to the breed’s trademark character and versatility.
As one of the oldest recognized breeds in the United States, the Quarter Horse has a rich history closely intertwined with that of America. Initially bred for quarter-mile races, the working Quarter Horse eventually found a niche on the western frontier.
Modern Quarter Horses thrive in a wide range of disciplines as pleasure and performance horses. But the breed has an increased risk of genetic diseases and health conditions requiring specialized nutrition and management.
This breed profile will discuss the history, characteristics, common health problems, and nutrition requirements of the American Quarter Horse. Keep reading to learn everything owners need to know about caring for and feeding their Quarter Horses.
Quarter Horse History
While the American Quarter Horse Association originated in 1940, the history of the Quarter Horse can be traced long before that to Colonial America. As the young country evolved, the Quarter Horse evolved with it.
Most horses in Colonial America were the descendants of hardy English stock, imported as working animals for settlers in the Colonies.
To produce a faster racehorse, American colonists began crossing the English stock with speedy ponies bred by the indigenous Cherokee and Chickasaw people. 
The Cherokee and Chickasaw ponies descended from Spanish Barbs initially brought to the Americas by Spanish explorers. Many of the free-roaming Mustangs of the American West can also trace their ancestry to these Spanish horses. 
The resulting cross excelled at sprinting short races of a quarter-mile distance, which earned the breed its name. These races often occurred down the main streets of small villages. 
In 1752, John Rudolph of Virginia imported the stallion Janus to improve the stamina of the short sprinters. Janus was a son of the Godolphin Arabian, a foundation sire of the Thoroughbred. 
After the American Revolution, the tall, sleek Thoroughbred gained popularity as the preferred racehorse on the newly established manicured racetracks of the Atlantic coast. 
The smaller, tougher Quarter Horse left the main streets of east coast villages as settlers moved west. Their hardiness from the original English stock, power from the Chickasaw ponies, and stamina from Janus made them well-suited to carry frontiersmen through the wilderness.
West of the Mississippi, these horses crossed with Mustangs to produce an equine with greater vigour for long working days on the range. The American Quarter Horse found its niche as a versatile cow horse there. 
The cattle industry of the American West grew exponentially after the Civil War. The Quarter Horse became essential to ranching operations, and ranchers purposefully bred the horses as dependable mounts for working cattle.
One of the most influential early bloodlines originated from the stallion Steel Dust in Texas. Cowboys revered the intelligence, speed, heavy muscle, and cow sense of the stallion’s descendants, and the “Steeldusts” played a pivotal role in shaping the breed standard. 
The American Quarter Horse Association, or AQHA, is the largest breed registry in the world. This association is the official governing body responsible for maintaining ownership records and cataloging all performance data on Quarter Horses.
The association aims to preserve the pedigree and integrity of the American Quarter Horse while promoting the welfare of its horses. AQHA also provides educational resources for current owners and people interested in Quarter Horse ownership.
The unique characteristics that made the Quarter Horse an ideal cow horse now make the breed a perfect match for many horse owners.
Quarter Horses are stock horses with relatively short stature and heavy muscular development. Most Quarter Horses are between 14 and 16 hands tall, with a typical weight of 900 to 1200 pounds.
Characteristic features of the American Quarter Horse include a short, wide head with small ears and a deep, broad chest. They are usually built more downhill than modern sport horses and have powerful, well-muscled hindquarters. 
Some Quarter Horse crosses, such as Appendix Quarter Horses, may have different physical characteristics depending on their breeding.
Common Quarter Horse colours include:
Quarter Horses are renowned for their willingness and trainability. In general, these horses have good temperaments and a docile disposition. However, personalities can vary between individuals depending on bloodlines.
Compared to other breeds, Quarter Horses are not considered particularly spooky or hot to ride or handle. The breed was developed to be a reliable mount that could work all day and safely carry its rider through varied environments.
Still, several factors influence temperament. Correct handling and training are essential for promoting appropriate behaviour in all horses, even breeds that are known for their good natures.
Many Quarter Horses still work today as cow horses in modern ranching operations. Quarter Horses are known for having an innate “cow sense” bred into them by generations of cowboys.
Today, the Quarter Horse is the breed of choice for competitive disciplines involving cattle, such as cutting and roping. However, the heritage of the American Quarter Horse also makes them a popular choice for western disciplines, including:
- Barrel racing
- Western pleasure
- Team penning
Quarter Horse breeding programs often focus on producing horses suited to excel at one of these disciplines. However, the Quarter Horse is a versatile mount for many disciplines, thanks to its temperament and athleticism.
Quarter Horses compete in nearly every type of arena, from hunter classes and low-level dressage to halter and showmanship. In addition, many owners enjoy their Quarter Horses as pleasure mounts and dependable trail riding partners.
Quarter Horse Health
No matter what you use your Quarter Horse for, proper management is essential for keeping him happy and healthy.
Most Quarter Horses are bred for a sturdy conformation that promotes long-term soundness. But some Quarter Horse bloodlines carry equine genetic diseases.
These diseases don’t have a cure, but testing and management can help limit adverse effects. 
Genetic diseases are caused by genes that horses inherit through their bloodlines. The AQHA has developed a five-panel disease test that allows horse owners to screen their horses for common genetic diseases in Quarter Horses.
These include glycogen branching enzyme deficiency (GBED), hereditary equine regional dermal asthenia (HERDA), hyperkalemic periodic paralysis (HYPP), malignant hyperthermia (MH), and polysaccharide storage myopathy (PSSM).
Glycogen Branching Enzyme Deficiency
GBED is an autosomal recessive disease caused by a mutation in the GBE1 gene. The mutation reduces the function of an enzyme involved in storing and mobilizing glycogen in the brain, liver, and muscle. 
Glycogen provides energy to the muscles, and impaired storage eventually leads to death. GBED usually results in stillbirths or abortions, and most foals that survive birth die within eight weeks. This disorder is always fatal. 
Hereditary Equine Regional Dermal Asthenia
Approximately 3.5% of Quarter Horses are carriers of HERDA, another autosomal recessive disease. In this disease, a mutation in the PPIB gene causes defective collagen formation. 
Collagen comprises connective tissues in the skin, bones, muscles, and cartilage. The defective collagen causes the outer layer of skin to split from the lower layers in horses with HERDA, sometimes leading to the entire skin sloughing off and leaving a raw wound. 
Young horses affected by this disease often have unusual cuts on the skin. Saddling these horses causes the skin to tear, and many horses wit