| Thoroughbred | ||
|---|---|---|
 Thoroughbred race horse | ||
| Distinguishing features: | Tall, slim horse, most notably used for racing | |
| Country of origin: | England | |
| Common nicknames: | Tb (abbreviation) | |
| Breed standards | ||
| The Jockey Club: | Stds | |
| Australian Stud Book: | Stds | |
| General Stud Book: | Stds | |
The Thoroughbred is a horse breed best known for its use in horse racing. Although the word "thoroughbred" is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed. Thoroughbreds are considered a "hot-blooded" horse, known for their agility, speed and spirit.
The Thoroughbred as it is known today was first developed in 17th and 18th century England, when native marescrossbred with imported Arabian stallions. All modern Thoroughbreds can trace their pedigrees to three stallions originally imported into England in the 1600s and 1700s, and to 74 foundation mares of English and Oriental (Arabian or Barb) blood. During the 1700s and 1800s, the Thoroughbred breed spread throughout the world; they were imported into North America starting in 1730 and into Australia, Europe, Japan and South America during the 1800s. Millions of Thoroughbreds exist worldwide today, with over 118,000 foals registered each year worldwide. were
Thoroughbreds are used mainly for racing, but are also bred for other riding disciplines, such as show jumping, combined training, dressage, polo, and fox hunting. They are also commonly cross-bred with other breeds to create new breeds or to improve existing ones, and have been influential in the creation of many important breeds, such as the Quarter Horse, the Standardbred, the Anglo-Arabian, and various Warmblood breeds.
Thoroughbred racehorses perform with maximum exertion, which has resulted in high rates of accidents and other health problems. Racing has been proven to have a higher fatality rate than all other legal human and animal sports. Also, Thoroughbreds are prone to other health complications, including bleeding from the lungs, low fertility, abnormally small hearts and a small hoof to body mass ratio. There are several theories for the reasons behind the prevalence of accidents and health problems in the Thoroughbred breed, and research continues into how to reduce the accident rate and treat those animals that are injured.
Terminology
The Thoroughbred is a distinct breed of horse, though people sometimes refer to a purebred horse of any breed as a "thoroughbred". The term for any horse or other animal that is derived from a single breed line is "purebred". While the term probably came into general use because the English Thoroughbred's General Stud Book was one of the first breed registries created, in modern usage, horse breeders consider it incorrect to refer to any horse or other animal as a "thoroughbred" except for horses belonging to the Thoroughbred breed. Nonetheless, breeders of other species of purebred animals may use the two terms interchangeably, though the term "thoroughbred" is not used as often for describing purebred animals of other species. The term is a proper noun referring to this specific breed, although it is often not capitalized, especially in non-specialist publications, and outside the US; for example, the Australian Stud Book, the New York Times, and the BBC do not capitalize the word.
Breed characteristics
The typical Thoroughbred ranges between 15.2 to 17.0 hands (hh) high, averaging 16 hh or 64 inches (1.6 m). They are most often bay, brown (dark bay), chestnut, black, or gray. Less common colors include roan and palomino. White is very rare, but is a recognized color separate from gray. The face and lower legs may be marked with white, but white will generally not appear on the body. Coat patterns that have more than one color on the body, such as Pinto or Appaloosa, do not exist in the Thoroughbred. Good quality Thoroughbreds have a well-chiseled head on a long neck, high withers, a deep chest, a short back, good depth of hindquarters, a lean body, and long legs. Thoroughbreds are classified among the "hot-blooded" breeds, which are animals bred for agility and speed and are generally considered spirited and bold.
Thoroughbreds that are born in the Northern Hemisphere technically become a year older on January 1 each year; those born in the Southern Hemisphere turn one year older on August 1. These artificial dates have been set to enable the standardization of races and other competitions for horses in certain age groups.
Registration, breeding, and population
About 37,000 Thoroughbred foals are registered each year in North America, with the largest numbers being registered in the states of Kentucky, Florida and California. Britain produces about 5,000 foals a year, and worldwide, there are more than 195,000 active broodmares, or females being used for breeding, and 118,000 newly registered foals in 2006 alone. The Thoroughbred industry is a large agribusiness, generating around $34 billion in revenue annually in the United States and providing about 470,000 jobs through a network of farms, training centers and race tracks.
Unlike a significant number of registered breeds today, a horse cannot be registered as a Thoroughbred (with The Jockey Club registry) unless conceived by "live cover"; that is, by the witnessed natural mating of a mare and a stallion. Artificial insemination (AI) and embryo transfer (ET), though commonly used and allowable in many other horse breed registries, cannot be used with Thoroughbreds. One reason is that a greater possibility of error exists in assigning parentage with AI, and although DNA and blood testing eliminate many of those concerns, AI still requires more detailed record keeping. The main reason, however, may be economic: a stallion has a limited number of mares who can be serviced by live cover. Thus, the practice prevents an oversupply of Thoroughbreds, though modern management still allows a stallion to live cover more mares in a season than once was thought possible. By allowing a stallion to cover only a couple hundred mares a year rather than the couple thousand possible with AI, it also preserves the high prices paid for horses of the finest or most popular lineages.
Concern exists that the closed stud book and tightly regulated population of the Thoroughbred is at risk of loss of genetic diversity because of the level of inadvertent inbreeding inevitable in such a small population. According to one study, 78% of alleles in the current population can be traced to 30 foundation animals, 27 of which are male. Ten foundation mares account for 72% of maternal (tail-female) lineages, and, as noted above, one stallion appears in 95% of tail male lineages. Thoroughbred pedigrees are generally traced through the maternal line, called the "distaff" line. The line that a horse comes from will often determine the price paid regardless of the actual talent or potential of the horse.
Uses
Although the Thoroughbred is primarily bred for racing, the breed is also used for show jumping and combined training because of its athleticism, and many retired and retrained race horses become fine family riding horses, dressage horses, and youth show horses. The larger horses are sought after for hunter/jumper and dressage competitions, whereas the smaller horses are in demand as polo ponies.
Horse racing
Thoroughbred horses are primarily bred for racing under saddle at the gallop. Thoroughbreds are often known for being either distance runners or sprinters, and their conformation usually reflects what they have been bred to do. Sprinters are usually well muscled, while stayers, or distance runners, tend to be smaller and slimmer. The size of the horse is one consideration for buyers and trainers when choosing a potential racehorse. Although there have been famous racehorses of every height, from Man o' War and Secretariat who both stood at 16.2 hands[93][94] to Hyperion (15.1), the best racehorses are generally of average size. Larger horses mature more slowly and have more stress on their legs and feet, making them more predisposed to lameness. Smaller horses are considered by some to be at a disadvantage due to their shorter stride and a tendency of other horses to bump them, especially in the starting gate. Historically, Thoroughbreds have steadily increased in size: the average height of a Thoroughbred in 1700 was about 13.3 hands high. By 1876 this had increased to 15.3. The United States champion racer Forego stood 17 hands. Statistically, fewer than 50% of all race horses ever win a race, and less than 1% ever win a stakes race such as the Kentucky Derby or the Epsom Derby.
In 2007, there were 71,959 horses who started races in the United States, and the average Thoroughbred racehorse in the United States and Canada ran 6.33 times in that year. In Britain, the British Racing Authority states there were 8,556 horses in training for flat racing for 2007, and those horses started 60,081 times in 5,659 races.
Horses finished with a racing career that are not suitable for breeding purposes often become riding horses or other equine companions. A number of agencies exist to help make the transition from the racetrack to another career, or to help find retirement homes for ex-racehorses.
Other disciplines
In addition to racing, Thoroughbreds compete in eventing, show jumping and dressage at the highest levels of international competition, including the Olympics. They are also used as show hunters, steeplechasers, and in western riding speed events such as barrel racing. Mounted police divisions employ them in non-competitive work, and recreational riders also use them. Thoroughbreds are one of the most common breeds for use in polofox hunting field as well. in the United States. They are often seen in the
Crossbreeding
Thoroughbreds are often crossed with horses of other breeds to create new breeds or improve existing ones. They have been influential on many modern breeds, including the American Quarter Horse,[105] the Standardbred, and possibly the Morgan, a breed that went on to influence many of the gaited breeds in North America. Other common crosses with the Thoroughbred include crossbreeding with Arabian bloodlines to produce the Anglo-Arabian as well as with the Irish Draught to produce the Irish Sport Horse. Thoroughbreds are often crossed with various Warmblood breeds due to their refinement and performance capabilities.
Health issues
Although Thoroughbreds are seen in the hunter-jumper world and in other disciplines, modern Thoroughbreds are primarily bred for speed, and racehorses have a very high rate of accidents as well as other health problems.
One tenth of all Thoroughbreds suffer orthopedic problems, including fractures. Current estimates indicate that there are 1.5 career-ending breakdowns for every 1,000 horses starting a race in the United States, an average of two horses per day. The State of California reported a particularly high rate of injury, 3.5 per 1000 starts, although it is interesting to note that several other countries do not suffer the same rate, with the United Kingdom having 0.9 injuries/1000 starts (1990-1999) and the courses in Victoria, Australia producing a rate of 0.44 injuries/1000 starts (1989-2004). Thoroughbreds also have other health concerns, including a majority of animals who are prone to bleeding from the lungs (Exercise Induced Pulmonary Hemorrhage), 10% with low fertility, and 5% with abnormally small hearts. Thoroughbreds also tend to have smaller hooves relative to their body mass than other breeds, with thin soles and walls and a lack of cartilage mass, which contributes to foot soreness, the most common source of lameness in racehorses.
Selective breeding
One argument for the health issues involving Thoroughbreds suggests that inbreeding is the culprit. It has also been suggested that capability for speed is enhanced in an already swift animal by raising muscle mass, a form of selective breeding that has created animals designed to win horse races. Thus, according to one theory, the modern Thoroughbred travels faster than its skeletal structure can support. Veterinarian Robert Miller states that "We have selectively bred for speeds that the anatomy of the horse cannot always cope with."
Poor breeding may be encouraged by the fact that many horses are sent to the breeding shed following an injury. If the injury is linked to a conformational fault, the fault is likely to be passed to the next generation. Additionally, some breeders will have a veterinarian perform straightening procedures on a horse with crooked legs. This can help increase the horse's price at a sale and perhaps help the horse have a sounder racing career, but the genes for poor legs will still be passed on.
Excess stress
A high accident rate may also occur because Thoroughbreds, particularly in the United States, are first raced as 2-year-olds, well before they are completely mature. Though they may appear full-grown and are in superb muscular condition, their bones are not fully formed. However, catastrophic injury rates are higher in 4- and 5-year-olds than in 2- and 3-year-olds. Some believe that correct, slow training of a young horse (including foals) may actually be beneficial to the overall soundness of the animal. This is because, during the training process, microfractures occur in the leg followed by bone remodeling. If the remodeling is given sufficient time to heal, the bone becomes stronger. If proper remodeling occurs before hard training and racing begins, the horse will have a stronger musculoskeletal system and will have a decreased chance of injury.
Medical challenges
The level of treatment given to injured Thoroughbreds is often more intensive than for horses of lesser financial value but also controversial, due in part to the significant challenges in treating broken bones and other major leg injuries. Leg injuries that are not immediately fatal still may be life-threatening because a horse's weight must be distributed evenly on all four legs to prevent circulatory problems, laminitis and other infections. If a horse loses the use of one leg temporarily, there is the risk that other legs will break down during the recovery period because they are carrying an abnormal weight load. While horses periodically lie down for brief periods of time, a horse cannot remain lying in the equivalent of a human's "bed rest" because of the risk of developing sores and internal damage and congestion.
Whenever a racing accident severely injures a well-known horse, such as the major leg fractures that led to the euthanization of 2006 Kentucky Derby winner Barbaro, or 2008 Kentucky Derby runner-up Eight Belles, animal rights groups have denounced the Thoroughbred racing industry. On the other hand, advocates of racing argue that without horse racing, far less funding and incentives would be available for medical and biomechanical research on horses. Although horse racing is hazardous, veterinary science has advanced. Previously hopeless cases can now be treated, and earlier detection through advanced imaging techniques like scintigraphy can keep at-risk horses off the track.
