The American QuarterHorse is the most popular breed in the United States today, and the American QuarterHorse Association is the largest breed registry in the world, with almost 3 million living American Quarter Horses registered in 2014. The compact body of the American QuarterHorse is well-suited for the intricate and quick maneuvers required in reining, cutting, working cow horse, barrel racing, calf roping, and other western riding events, especially those involving live cattle.
The American QuarterHorse is also used in English disciplines, driving, show jumping, dressage, hunting, and many other equestrian activities. In the 1600s on the Eastern seaboard of what today is the United States began to breed imported English Thoroughbred horses with assorted “native” horses.
One of the most famous of these early imports was Janus, a Thoroughbred who was the grandson of the Go dolphin Arabian. The influence of Thoroughbreds likes Janus contributed genes crucial to the development of the colonial QuarterHorse “.
As flat racing became popular with the colonists, the QuarterHorse gained even more popularity as a sprinter over courses that, by necessity, were shorter than the classic racecourses of England. These courses were often no more than a straight stretch of road or flat piece of open land.
When competing against a Thoroughbred, local sprinters often won. As the Thoroughbred breed became established in America, many colonial Quarter Horses were included in the original American stud books.
This began a long association between the Thoroughbred breed and what would later become officially known as the QuarterHorse “, named after the 1 4 mile (0.40 km) race distance at which it excelled. In the 19th century, pioneers heading West needed a hardy, willing horse.
On the Great Plains, settlers encountered horses that descended from the Spanish stock Hernán Cortés and other Conquistadors had introduced into the viceroyalty of New Spain, which today includes the Southwestern United States and Mexico. The horses of the West included herds of feral animals known as Mustangs, as well as horses domesticated by Native Americans, including the Comanche, Shoshone and New Peace tribes.
Another early foundation sire for the breed was , foaled in 1828, who tracks his lineage through the Barley Turk, a foundation sire of the Thoroughbred horse breed. The main duty of the ranch horse in the American West was working cattle.
Even after the invention of the automobile, horses were still irreplaceable for handling livestock on the range. The skills required by cowboys and their horses became the foundation of the rodeo, a contest which began with informal competition between cowboys and expanded to become a major competitive event throughout the west.
To this day, the QuarterHorse dominates in events that require speed as well as the ability to handle cattle. As a result, more Thoroughbred blood was added into the developing American QuarterHorse breed.
The American QuarterHorse also benefited from the addition of Arabian, Morgan, and even Standard bred bloodlines. In 1940, the American QuarterHorse Association (Aqua) was formed by a group of horsemen and ranchers from the Southwestern United States dedicated to preserving the pedigrees of their ranch horses.
After winning the 1941 Fort Worth Exposition and Fat Stock Show grand champion stallion, the horse honored with the first registration number, P-1, was Wimpy, a descendant of the King Ranch foundation sire Old Sorrel. Other sires alive at the founding of the Aqua were given the earliest registration numbers Joe Reed P-3, Chief P-5, Oklahoma Star P-6, Cowboy P-12, and Wagoner's Rainy Day P-13.
The Thoroughbred race horse Three Bars, alive in the early years of the Aqua, is recognized by the American QuarterHorse Hall of Fame as one of the significant foundation sires for the QuarterHorse breed. Other significant Thoroughbred sires seen in early Aqua pedigrees include Rocket Bar, Top Deck and Depth Charge.
Since the American QuarterHorse was formally established as a breed, the Aqua stud book has remained open to additional Thoroughbred bloods via a performance standard. The resulting offspring is registered in the “appendix” of the American QuarterHorse Association's studbook, hence the nickname.
Horses listed in the appendix may be entered in competition, but offspring are not initially eligible for full Aqua registration. If the Appendix horse meets certain conformation criteria and is shown or raced successfully in sanctioned Aqua events, the horse can earn its way from the appendix into the permanent studbook, making its offspring eligible for Aqua registration.
Some breeders argue that the continued addition of Thoroughbred bloodlines are beginning to compromise the integrity of the breed standard. European nations such as Germany and Italy have imported large numbers of Quarter Horses.
Next to the American QuarterHorse Association (which also encompasses Quarter Horses from Canada), the second largest registry of Quarter Horses is in Brazil, followed by Australia. The British American QuarterHorse breed society is the AQHA-UK.
With the internationalization of the discipline of reining and its acceptance as one of the official seven events of the World Equestrian Games, there is a growing international interest in Quarter Horses. The American QuarterHorse is the most popular breed in the United States today, and the American QuarterHorse Association is the largest breed registry in the world, with nearly 3 million American Quarter Horses registered worldwide in 2014.
A halter-type QuarterHorse The QuarterHorse has a small, short, refined head with a straight profile, and a strong, well-muscled body, featuring a broad chest and powerful, rounded hindquarters. They usually stand between 14 and 16 hands (56 and 64 inches, 142 and 163 cm) high, although some Halter-type and English hunter-type horses may grow as tall as 17 hands (68 inches, 173 cm).
The stock horse type is shorter, more compact, stocky and well-muscled, yet agile. The racing and hunter type Quarter Horses are somewhat taller and smoother muscled than the stock type, more closely resembling the Thoroughbred.
Other recognized colors include bay, black, brown, buckskin, palomino, gray, dun, red dun, grille (also occasionally referred to as blue dun), red roan, blue roan, bay roan, per lino, cello, and white. In the past, spotted color patterns were excluded, but now with the advent of DNA testing to verify parentage, the registry accepts all colors as long as both parents are registered.
Horses shown in-hand in Halter competition are larger yet, with a very heavily muscled appearance, while retaining small heads with wide jowls and refined muzzles. There is controversy amongst owners, breeder and veterinarians regarding the health effects of the extreme muscle mass that is currently fashionable in the specialized halter horse, which typically is 15.2 to 16 hands (62 to 64 inches, 157 to 163 cm) and weighs in at over 1,200 pounds (540 kg) when fitted for halter competition.
Not only are there concerns about the weight to frame ratio on the horse's skeletal system, but the massive build is also linked to hyperkalemic periodic paralysis (Hype) in descendants of the stallion Impressive (see Genetic diseases below). A QuarterHorse warming up for hunt seat competition QuarterHorse race horses are bred to sprint short distances ranging from 220 to 870 yards.
Quarter Horses race primarily against other Quarter Horses, and their sprinting ability has earned them the nickname, “the world's fastest athlete.” The show hunter type is slimmer, even more closely resembling a Thoroughbred, usually reflecting a higher percentage of appendix breeding.
There are several genetic diseases of concern to QuarterHorse breeders: Hyperkalemic periodic paralysis (Hype), which is caused by an autosomal dominant gene linked to the stallion Impressive.
There is a DNA test for Hype, which is required by the Aqua. Since 2007, the Aqua bars registration of horses who possess the homozygous form (H/H) of the gene, and though heterozygous (H/N) horses are still eligible for registration, altering that status is currently being discussed.
Additionally, all Quarter Horses born 2007 or later that are confirmed to be descendants of Impressive must carry a note about the risks of Hype on their registration papers. Due to Hype, the halter classes are undergoing significant changes.
Halter classes are dominated by the Impressive bloodline. Impressive, a very prolific halter horse, brought to the stock breeds the muscle mass that is popular in halter competition today.
This muscle mass is linked to Hype, and as the condition is reduced within the breed, the style of horse in halter classes is also likely to change. Already there have been rule changes, including the creation of a “Performance Halter class” in which a horse must possess a Register of Merit in performance or racing before it can compete.
A causative mutated allele, anodyne receptor 1 gene (RyR1) at nucleotide C7360G, generating a R2454G amino acid substitution. has been identified in the American Quarter Horse and breeds with Quarter Horse ancestry, inherited as an autosomal dominant It can be caused by overwork, anesthesia, or stress.
Hereditary Equine Regional Dermal Athenian (Herd), also known as hyperkeratosis cuts (HC). When a horse has this disease, there is a collagen defect that results in the layers of skin not being held firmly together.
Thus, when the horse is ridden under saddle or suffers trauma to the skin, the outer layer often splits or separates from the deeper layer, or it can tear off completely. Most horses with Herd are euthanized for humane reasons between the age of two and four years.
The very hotly debated and controversial theory, put forth by researchers at Cornell University and Mississippi State University is that the sire line of the great foundation stallion Polo Buena is implicated as the origin of the disease. As of May 9, 2007, Researchers working independently at Cornell University and at the University of California, Davis announced that a DNA test for Herd has been developed.
Glycogen Branching Enzyme Deficiency (Bed) is a genetic disease where the horse is lacking an enzyme necessary for storing glycogen, the horse's heart muscle and skeletal muscles cannot function, leading to rapid death. The disease occurs in foals who are homozygous for the lethal Bed allele, meaning both parents carry one copy of the gene.
Equine polysaccharide storage myopathy, also called EPSM or PSM, is a metabolic muscular condition in horses that causes tying up, and is also related to a glycogen storage disorder. While also seen in some draft horse breeds, PSM has been traced to three specific but undisclosed bloodlines in Quarter Horses, with an autosomal recessive inheritance pattern.
48% of Quarter Horses with symptoms of neuromuscular disease have PSM. To some extent it can be diet controlled with specialized low-starch diets, but genetic testing is advised before breeding, as the condition exists at a subclinical level in approximately 6% of the general Quarter Horse population.
Although dropout Quarter Horses with Paint markings were not allowed to be registered for many years, the gene for such markings is a recessive and continued to periodically appear in Quarter Horse foals. Thus, it is believed that some Quarter Horses may carry the gene for Lethal White Syndrome.
Cleft Palate Birth defect, this is not just a genetic disorder. It can be caused from genetics, hormones, mineral deficiency, tranquilizers, or steroids.
The surgery to repair the cleft palate does not have a high success rate. Some observations of a horse with a cleft palate and no surgery are: lifting head high when eating, dropping head low to drink, coughing when beginning of exercise, and placing workers or other oral medications in the side of the jaw and taking about hour to administer full dose.
4–8 ^ Reinhardt Quarter Running Horse pp. ^ Dotson, Judith (2012), Story's Illustrated Guide to 96 Horse Breeds of North America, Story Publishing, p. 64, ISBN 9781603429184 ^ Iowa Quarter Horse Racing Association.
Lost Bloodline ^ Sir Arch ^ History of the Quarter Horse ^ Down, Ryan; Cohen, Noah D; Sawyer, Jason; Affair, Cousin; Johnson, Charlie D; Din dot, Scott V (2012). “Whole-Genome sequencing and genetic variant analysis of a quarter Horse mare”.
^ American Quarter Horse Association Combined Stud Book 1-2-3-4-5 p. 1 ^ “Three Bars (TB)” (PDF). ^ Wiggins Great American Speed horse p. 166 ^ “Documents and Forms”.
National Foundation Quarter Horse Association. The Official Horse Breeds Standards Guide: The Complete Guide to the Standards of All North American Equine Breed Associations.
^ “Details on Aqua Hip rules for registration”. “Malignant Hyperthermia Associated with Anodyne Receptor 1 (C7360G) Mutation in Quarter Horses”.
^ Lens, Tom R. “Heritable Diseases of the American Quarter Horse and Their Management” (PDF). Val berg SJ, Michelson JR, Gallant EM, Maclean JM, Lent L, DE la Core F (1999).
“Exertional rhabdomyolysis in quarter horses and thoroughbreds: one syndrome, multiple etiologies”. ^ “Herd: DNA Tests Available for Disfiguring Skin Disease”.
“Glycogen Branching Enzyme Deficiency (Bed) in Horses”. ^ Val berg et al., Exertional rhabdomyolysis in quarter horses and thoroughbreds “, Equine Vet Journal Supplement, pp.
Purdue University, Animal Disease Diagnostic Lab. “Clinical characteristics of horses and foals diagnosed with cleft palate in a referral population: 28 cases (1988–2011)”.
Val berg SJ, Michelson JR, Gallant EM, Maclean JM, Lent L, DE la Core F (July 1999). “Exertional rhabdomyolysis in quarter horses and thoroughbreds: one syndrome, multiple etiologies”.