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{{short description|Horse breed developed for racing}}
{{use mdy dates|date=May 2023}}
{{Other uses}}
{{pp-move-vandalism|small=yes}}

{{Infobox horse
|name=Thoroughbred
|image= Applebite-Gentlemen.jpg
|image_caption= Thoroughbred horse
|features= Athletic riding horse breed, used for racing and many equestrian sports
|altname=
|alt=A chestnut-colored horse standing in a stableyard
|nickname=Tb (abbreviation); Bloodhorse
|country= England
|group1= The Jockey Club (US)
|std1= https://www.registry.jockeyclub.com/registry.cfm?page=tjcRuleBook
|group2= Australian Stud Book
|std2= http://www.studbook.org.au/DisplayPDF.aspx?ty=RULES
|group3= General Stud Book
|std3= https://www.weatherbys.co.uk/Weatherbys/media/PDFs/gsb-conditions.pdf
}}

The '''Thoroughbred''' is a [[list of horse breeds|horse breed]] developed for [[Thoroughbred racing|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 "[[Hot-blooded horse|hot-blooded]]" horses that are known for their agility, speed, and spirit.

The Thoroughbred, as it is known today, was developed in 17th- and 18th-century England, when native [[mare]]s were [[Crossbreed|crossbred]] with imported  [[stallion (horse)|stallions]] of [[Arabian horse|Arabian]], [[Barb horse|Barb]], and [[Turkoman horse|Turkoman]] breeding. All modern Thoroughbreds can trace their pedigrees to three stallions originally imported into England in the 17th and 18th centuries, and to a larger number of [[foundation bloodstock|foundation]] mares of mostly English breeding. During the 18th and 19th centuries, 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 19th century. Millions of Thoroughbreds exist today, and around 100,000&nbsp;[[foal]]s are registered each year worldwide.

Thoroughbreds are used mainly for racing, but are also bred for other riding disciplines such as [[show jumping]], [[Eventing|combined training]], [[dressage]], [[polo]], and [[fox hunting]]. They are also commonly crossbred to create new breeds or to improve existing ones, and have been influential in the creation of the [[American Quarter Horse|Quarter Horse]], [[Standardbred horse|Standardbred]], [[Anglo-Arabian]], and various [[warmblood]] breeds.

Thoroughbred racehorses perform with maximum exertion, which has resulted in [[Racehorse injuries|high accident rates]] and health problems such as [[Exercise induced pulmonary hemorrhage|bleeding from the lungs]]. Other health concerns include 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 on the subject is ongoing.

==Breed characteristics==
[[File:Rock of Gibraltar - Race Horse.jpg|thumb|upright|left|Thoroughbreds have a well-chiseled head.|alt=Brown horse looking out over a railing. The head is sideways to the camera and the horse is looking into the distance.]]
The typical Thoroughbred ranges from {{hands|15.2|to|17.0}} high, averaging {{hands|16|lk=off}}. They are most often [[Bay (horse)|bay]], dark bay or [[Seal brown (horse)|brown]], [[chestnut (coat)|chestnut]], [[black (horse)|black]], or [[gray (horse)|gray]].<ref name="Patten">Patten ''Light Horse Breeds'' pp. 191–195</ref> Less common colors recognized in the United States include [[roan (horse)|roan]] and [[palomino]]. [[White (horse)|White]] is very rare, but is a recognized color separate from gray.<ref name="color">{{cite web |author= |title=Coat Colors Of Thoroughbreds |url=https://www.registry.jockeyclub.com/registry.cfm?page=dotRegistryIdentifyThoroughbred&CFID=7216657&CFTOKEN=94423595 |access-date=2008-02-17 |work=Interactive RegistrationTM Help Desk: How to Identify a Thoroughbred |publisher=The Jockey Club}}</ref> The face and lower legs may be [[horse markings|marked]] with white,<ref name=Guide12>Bongianni ''Simon & Schuster's Guide to Horses and Ponies'' section 12</ref> but white will generally not appear on the body. Coat patterns that have more than one color on the body, such as [[Pinto horse|Pinto]] or [[Appaloosa]], are not recognized by mainstream breed registries.<ref name=color/><ref>{{cite web|title=Approved Veterinarian Identification of the Thoroughbred in Australia|url=http://www.studbook.org.au/DisplayPDF.aspx?ty=VET|date=May 2008|access-date=2009-02-25|publisher=Australian Stud Book}}</ref> 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.<ref name=Guide12/><ref name=Montgomery338>Montgomery ''The Thoroughbred'' pp. 338–354</ref> Thoroughbreds are classified among the "hot-blooded" breeds, which are animals bred for agility and speed and are generally considered spirited and bold.<ref>Henry ''All About Horses'', pp. 60, 66.</ref>

Thoroughbreds born in the [[Northern Hemisphere]] are officially considered a year older on the first of January each year;<ref name="Rule3">{{cite web |author= |title=Eligibility for Foal Registration |url=http://www.jockeyclub.com/registry.asp?section=3#one |archive-url=https://web.archive.org/web/20080112093116/http://www.jockeyclub.com/registry.asp?section=3#one |archive-date=Jan 12, 2008 |access-date=2008-02-17 |work=The American Stud Book Principal Rules and Requirements |publisher=The Jockey Club |pages=Section V, part C}}</ref> those born in the [[Southern Hemisphere]] officially are one year older on the first of August.<ref name="OzSBRules">{{cite web |author= |year=2007 |title=Rules of the Australian Stud Book |url=http://www.studbook.org.au/DisplayPDF.aspx?ty=RULES |access-date=2008-02-17 |publisher=Australian Jockey Club |page=7 |format=PDF}}</ref> These artificial dates have been set to enable the standardization of races and other competitions for horses in certain age groups.<ref name=TrackTalk38>Phifer ''Track Talk'' p. 38</ref>{{clear}}

==Terminology==
The Thoroughbred is a distinct breed of horse, although people sometimes refer to a [[purebred]] horse of any breed as a ''thoroughbred''. The term for any horse or other animal derived from a single [[breed]] line is ''[[purebred]]''.<ref name="Merriam-Webster">{{cite book |url= https://books.google.com/books?id=2yJusP0vrdgC&q=purebred+of+thoroughbred&pg=RA3-PA905 |title=Thoroughbred entry |access-date=2008-02-17 |author=Merriam-Webster |year=1994 |series= Merriam-Webster's Dictionary of English Usage |publisher=Merriam Webster |page=195 |isbn= 978-0-87779-132-4}}</ref><ref name=MW905>Merriam-Webster ''The Merriam-Webster Dictionary of English Usage'' p. 905</ref> While the term probably came into general use because the English Thoroughbred's [[General Stud Book]] was one of the first [[breed registry|breed registries]] created, in modern usage horse breeders consider it incorrect to refer to any animal as a ''thoroughbred'' except for horses belonging to the Thoroughbred breed.<ref name="Merriam-Webster"/> Nonetheless, breeders of other species of purebred animals may use the two terms interchangeably,<ref name=MW905/> though ''thoroughbred'' is less often used for describing purebred animals of other species.<ref name="Merriam-Webster"/><ref name=MW905/> The term is a [[Noun#Proper nouns and common nouns|proper noun]] referring to this specific breed,<ref name="IMH"/> though often not capitalized, especially in non-specialist publications, and outside the US. For example, the Australian Stud Book,<ref>{{cite web |url= https://thoroughbredwelfare.horse/ |title=Thoroughbred Welfare |access-date=2021-01-16 |work=Australian Stud Book Website |publisher= Racing Australia}}</ref> ''[[The New York Times]]'',<ref>{{cite web |url= https://query.nytimes.com/search/query?query=thoroughbred&srchst=nyt |title=Search of the New York Times Website for Thoroughbred |access-date=2008-06-07 |author=New York Times |work=[[The New York Times]] Website }}</ref> and the [[BBC]] do not capitalize the word.<ref>{{cite web |url=http://search.bbc.co.uk/cgi-bin/search/results.pl?go=homepage&scope=all&tab=all&q=thoroughbred&Search=Search |title= Search of the BBC Website for Thoroughbred |access-date=2008-06-07 |author=BBC |work=BBC Website |publisher=BBC}}</ref>

==History==
[[File:Darley Arabian.jpg|thumb |The Darley Arabian, one of the three traditional [[foundation bloodstock|foundation sires]] of the Thoroughbred|alt=Painting of a brown horse walking behind a man in a blue seventeenth century outfit.]]

===Beginnings in England===

====Early racing====
[[Flat racing]] existed in England by at least 1174, when four-mile races took place at [[Smithfield, London|Smithfield]], in London. Racing continued at fairs and markets throughout the [[Middle Ages]] and into the reign of King [[James I of England]]. It was then that [[handicapping]], a system of adding weight to attempt to equalize a horse's chances of winning as well as improved training procedures, began to be used. During the reigns of [[Charles II of England|Charles II]], [[William III of England|William III]], [[Anne, Queen of Great Britain|Anne]], and [[George I of Great Britain|George I]], the foundation of the Thoroughbred was laid.<ref name=Wall7/> The term "thro-bred" to describe horses was first used in 1713.<ref name=Barrett1995>Barrett ''Daily Telegraph Chronicle of Horse Racing'' p. 9</ref>

Under Charles II, a keen racegoer and owner, and Anne, royal support was given to racing and the breeding of race horses. With royal support, horse racing became popular with the public, and by 1727, a newspaper devoted to racing, the ''Racing Calendar'', was founded. Devoted exclusively to the sport, it recorded race results and advertised upcoming meets.<ref name=Wall7>Wall ''Famous Running Horses'' pp. 7–8</ref>

====Foundation stallions====
All modern Thoroughbreds trace their origin to one of three stallions imported into England from the Middle East in the late 17th and early 18th centuries: the [[Byerley Turk]] (1680s), the [[Darley Arabian]] (1704), and the [[Godolphin Arabian]] (1729).<ref>Milner ''The Godolphin Arabian'' pp. 3–6</ref><ref>Wall ''Famous Running Horses'' p. 8</ref> Other imported stallions were less influential, but still made noteworthy contributions to the breed. These included the [[Alcock's Arabian]],<ref name=Willet25>Willett ''The Thoroughbred'' p. 25</ref> D'Arcy's White Turk, Leedes Arabian, and [[Curwen's Bay Barb]].<ref name=TrackTalk45>Phifer ''Track Talk'' p. 45</ref><ref name=Morris>Morris ''Thoroughbred Stallions'' pp. 1–2</ref>{{refn|Articles on the mentioned horses are located at {{cite web |url=http://www.tbheritage.com/HistoricSires/FoundationSires/FSDarcyWhite.html |title= Foundation Sires of the Thoroughbred: D'Arcy's White Turk |access-date=2008-02-17 |author=Peters, Anne |work= Foundation Sires of the Thoroughbred |publisher=Thoroughbred Heritage}}, {{cite web |url=http://www.tbheritage.com/HistoricSires/FoundationSires/FoundSiresL.html |title= Foundation Sires of the Thoroughbred: L |access-date=2008-02-17 |work= Foundation Sires of the Thoroughbred |publisher=Thoroughbred Heritage}}, {{cite web |url=http://www.tbheritage.com/HistoricSires/FoundationSires/FSCurwensBayBarb.html |title= Foundation Sires of the Thoroughbred: Curwen's Bay Barb |author=Peters, Anne |access-date=2008-02-17 |work= Foundation Sires of the Thoroughbred |publisher=Thoroughbred Heritage}}|group=notes}} Another was the Brownlow Turk, who, among other attributes, is thought to be largely responsible for the [[gray (horse)|gray]] coat color in Thoroughbreds.<ref name=Willet25/> In all, about 160 stallions have been traced in the historical record as contributing to the creation of the Thoroughbred. The addition of horses of Eastern bloodlines, whether Arabian, Barb, or Turk, to the native English mares<ref name=Willett22>Willett ''The Thoroughbred'' pp. 22-23</ref> ultimately led to the creation of the [[General Stud Book]] (GSB) in 1791 and the practice of official [[breed registry|registration]] of horses.<ref name="IMH">{{cite web |url=http://www.imh.org/History-of-the-Horse/Breeds-of-the-World-by-Continent/Thoroughbred.html |title=Thoroughbred |access-date=2012-04-01 |work=Horse Breeds of the World |publisher=International Museum of the Horse |archive-url=https://web.archive.org/web/20180726071831/http://www.imh.org/History-of-the-Horse/Breeds-of-the-World-by-Continent/Thoroughbred.html |archive-date=2018-07-26 |url-status=dead}}</ref> According to Peter Willett, about 50% of the foundation stallions appear to have been of Arabian bloodlines, with the remainder being evenly divided between Turkoman and Barb breeding.<ref name=Willett22/>{{refn|The identification of exact breeding for most of the foundation stallions is complicated by the practice in the 17th and 18th centuries of calling a horse an Arab or a Barb based on where the horse was acquired, rather than from its actual breeding.<ref name=Willett19>Willett ''The Thoroughbred'' p. 19</ref>|group=notes}}

[[File:Matchem.jpg|thumb |Matchem, a grandson of the Godolphin Arabian, from a painting by [[George Stubbs]]|alt=Painting of a standing next to two men, one of whom is holding the horse's bridle, the other is pouring water into a water trough.]]

Each of the three major [[foundation bloodstock|foundation sires]] was, coincidentally, the ancestor of a grandson or great-great-grandson who was the only male descendant to perpetuate each respective horse's male line: [[Matchem]] was the only descendant of his grandsire, the Godolphin Arabian, to maintain a [[Patrilineality|male line]] to the present;<ref name=Milner140>Milner ''The Godolphin Arabian'' p. 140</ref> the Byerley Turk's male line was preserved by [[Herod (horse)|Herod]] (or King Herod), a great-great-grandson;<ref name=Willett38>Willett ''The Thoroughbred'' pp. 38–39</ref> and the male line of the Darley Arabian owes its existence to great-great-grandson [[Eclipse (horse)|Eclipse]], who was the dominant racehorse of his day and never defeated.<ref name=TrackTalk45/><ref name=Willett37>Willett ''The Thoroughbred'' p. 37</ref> One genetic study indicates that 95% of all male Thoroughbreds trace their direct male line (via the [[Y chromosome]]) to the Darley Arabian.<ref name="Pickrell">{{cite magazine|url=https://www.newscientist.com/article/dn7941-95-of-thoroughbreds-linked-to-one-superstud/|title=95% of thoroughbreds linked to one superstud|last=Pickrell|first=John|magazine=[[New Scientist]]|date=2005-09-06|access-date=2019-09-21}}</ref>

However, in modern Thoroughbred pedigrees, most horses have more crosses to the Godolphin Arabian (13.8%) than to the Darley Arabian (6.5%) when all lines of descent (maternal and paternal) are considered. Further, as a percentage of contributions to current Thoroughbred bloodlines, Curwen's Bay Barb (4.2%) appears more often than the Byerley Turk (3.3%). The majority of modern Thoroughbreds alive today trace to a total of only 27 or 28 stallions from the 18th and 19th&nbsp;centuries.<ref name="Pickrell"/><ref name="Cunningham">{{cite journal | pmid = 11736806 | doi=10.1046/j.1365-2052.2001.00785.x | volume=32 | title=Microsatellite diversity, pedigree relatedness and the contributions of founder lineages to thoroughbred horses | date=December 2001 | journal=Anim. Genet. | pages=360–4 | last1 = Cunningham | first1 = EP | last2 = Dooley | first2 = JJ | last3 = Splan | first3 = RK | last4 = Bradley | first4 = DG| issue=6 }}</ref>

====Foundation mares====
The [[mare]]s used as foundation breeding stock came from a variety of breeds, some of which, such as the [[Irish Hobby]], had developed in northern Europe prior to the 13th&nbsp;century.<ref name="mtDNA3">Erigero [http://www.tbheritage.com/GeneticMarkers/mtdnaintbdamlines3.html "Who's Your Momma III"] ''Animal Genetics''</ref> Other mares were of oriental breeding, including Barb, [[Turkoman horse|Turk]] and other bloodlines,<ref name="mtDNA2">Erigero [http://www.tbheritage.com/GeneticMarkers/mtdnaintbdamlines3.html "Who's Your Momma II"] ''Animal Genetics''</ref> although most researchers conclude that the number of Eastern mares imported into England during the 100 years after 1660 was small.<ref name=Willett22/> The 19th-century researcher Bruce Lowe identified 50&nbsp;mare "families" in the Thoroughbred breed, later augmented by other researchers to 74.<ref name="mtDNA1">Erigero [http://www.tbheritage.com/GeneticMarkers/mtdnaintbdamlines.html "New Research Sheds Light on Old Pedigrees"] ''Animal Genetics''</ref> However, it is probable that fewer genetically unique mare lines existed than Lowe identified.<ref name="mtDNA1"/> Recent studies of the [[Mitochondrial DNA|mtDNA]] of Thoroughbred mares indicate that some of the mare lines thought to be genetically distinct may actually have had a common ancestor; in 19&nbsp;mare lines studied, the [[haplotype]]s revealed that they traced to only 15&nbsp;unique foundation mares, suggesting either a common ancestor for foundation mares thought to be unrelated or recording errors in the GSB.<ref name="mtDNA1"/>

===Later development in Britain===
By the end of the 18th century, the English [[British Classic Races|Classic races]] had been established. These are the [[St. Leger Stakes]], founded in 1776, [[Epsom Oaks|The Oaks]], founded in 1779, and [[Epsom Derby|The Derby]] in 1780. Later, the [[2,000 Guineas Stakes|2,000&nbsp;Guineas Stakes]] and the [[1,000 Guineas Stakes]] were founded in 1809 and 1814. The 1,000&nbsp;Guineas and the Oaks are restricted to [[filly|fillies]], but the others are open to racehorses of either sex aged three years. The distances of these races, ranging from {{convert|1|mi|spell=in}} to {{convert|1.75|mi}}, led to a change in breeding practices, as breeders concentrated on producing horses that could race at a younger age than in the past and that had more speed. In the early 18th&nbsp;century, the emphasis had been on longer races, up to {{convert|4|mi}}, that were run in multiple heats. The older style of race favored older horses, but with the change in distances, younger horses became preferred.<ref name=Classic34>Willett ''The Classic Racehorse'' pp. 34–36</ref>

Selective breeding for speed and racing ability led to improvements in the size of horses and winning times by the middle of the 19th&nbsp;century. [[Bay Middleton (horse)|Bay Middleton]], a winner of the Epsom Derby, stood over 16&nbsp;hands high, a full hand higher than the Darley Arabian. Winning times had improved to such a degree that many felt further improvement by adding additional Arabian bloodlines was impossible. This was borne out in 1885, when a race was held between a Thoroughbred, Iambic, considered a mid-grade runner, and the best Arabian of the time, Asil. The race was over {{convert|3|mi|m}}, and although Iambic was [[Handicap (horse racing)|handicapped]] by carrying {{convert|4.5|st|kg lb}} more than Asil, he still managed to beat Asil by 20&nbsp;lengths.<ref name=Classic39>Willett ''The Classic Racehorse'' pp. 39–41</ref> The improvement of the breed for racing in this way was said by noted 19th century racing writer, Nimrod, to have created "the noblest animal in the creation".{{sfn|Nimrod|1901|p=5}}

An aspect of the modern British breeding establishment is that they breed not only for flat racing, but also for [[Steeplechase (horse racing)|steeplechasing]].<ref name=Classic57>Willett ''The Classic Racehorse'' p. 57</ref> Up until the end of the 19th century, Thoroughbreds were bred not only for racing but also as saddle horses.<ref name=Derry31>Derry ''Horses in Society'' p. 41</ref>

Soon after the start of the 20th&nbsp;century, fears that the English races would be overrun with American-bred Thoroughbreds because of the closing of US racetracks in the early 1910s, led to the [[Jersey Act]] of 1913.<ref name=Classic111>Willett ''The Classic Racehorse'' pp. 111–113</ref> It prohibited the registration of any horse in the General Stud Book (GSB) if they could not show that every ancestor traced to the GSB. This excluded most American-bred horses, because the 100-year gap between the founding of the GSB and the American Stud Book meant that most American-bred horses possessed at least one or two crosses to horses not registered in the GSB. The act was not repealed until 1949, after which a horse was only required to show that all its ancestors to the ninth generation were registered in a recognized Stud Book.<ref name=Classic71>Willett ''The Classic Racehorse'' pp. 71–74</ref> Many felt that the Jersey Act hampered the development of the British Thoroughbred by preventing breeders in the United Kingdom from using new bloodlines developed outside the British Isles.<ref name=Classic56>Willett ''The Classic Racehorse'' p. 56</ref>

===In America===
[[Image:Diomed.jpg|thumb|Diomed, an important sire in American Thoroughbred breeding.]]
The first Thoroughbred horse in the [[Thirteen Colonies|American Colonies]] was [[Bulle Rock]], imported in 1730.<ref name="Robertson16">Robertson ''History of Thoroughbred Racing in America'' p. 16</ref><ref name="ASB10">Bruce ''The American Stud Book'' Volume 1 p. 10</ref> [[Maryland]] and [[Virginia]] were the centers of Colonial Thoroughbred breeding, along with [[South Carolina]] and New York. During the [[American Revolution]] importations of horses from England practically stopped but were restarted after the signing of a peace treaty. Two important stallions were imported around the time of the Revolution; [[Messenger (horse)|Messenger]] in 1788 and [[Diomed]] before that.

Messenger left little impact on the American Thoroughbred, but is considered a foundation sire of the [[Standardbred horse|Standardbred]] breed. Diomed, who won the Derby Stakes in 1780, had a significant impact on American Thoroughbred breeding, mainly through his son [[Sir Archy]].<ref name="Montgomery">Montgomery ''The Thoroughbred'' pp. 131–136</ref><ref name="DerbyWins">{{cite web |title=Turf Hallmarks: Epsom Derby Stakes |url=http://www.tbheritage.com/TurfHallmarks/racecharts/epderby.html |url-status=dead |archive-url=https://web.archive.org/web/20080302082133/http://www.tbheritage.com/TurfHallmarks/racecharts/epderby.html |archive-date=2008-03-02 |access-date=2008-02-17 |work=Turf Hallmarks |publisher=Thoroughbred Heritage}}</ref> John F. Wall, a racing historian, said that Sir Archy was the "first outstanding stallion we can claim as native American."<ref name="Wall114">Wall ''Famous Running Horses'' pp. 114–115</ref> He was retired from the racetrack because of lack of opponents.<ref name=Wall114/> Medley and Shark, who arrived in the [[United States]] before Messenger and Diomed, became important [[broodmare]] and dam sires by producing [[foundation stock]], and their daughters and granddaughters were bred primarily to [[Diomed]].

After the American Revolution, the center of Thoroughbred breeding and racing in the United States moved west. [[Kentucky]] and [[Tennessee]] became significant centers. [[Andrew Jackson]], later [[President of the United States]], was a breeder and racer of Thoroughbreds in Tennessee.<ref name=Montgomery142>Montgomery ''The Thoroughbred'' pp. 142–143</ref> Match races held in the early 19th&nbsp;century helped to popularize horse racing in the United States. One took place in 1823, in [[Long Island|Long Island, New York]], between Sir Henry and [[American Eclipse (racehorse)|American Eclipse]]. Another was a [[match race]] between [[Boston (horse)|Boston]] and [[Fashion (horse)|Fashion]] in 1838 that featured bets of $20,000 from each side.<ref name=Montgomery143>Montgomery ''The Thoroughbred'' pp. 143–147</ref> The last major match races before the [[American Civil War]] were both between [[Lexington (horse)|Lexington]] and Lecompte. The first was held in 1854 in [[New Orleans]] and was won by Lecompte. Lexington's owner then challenged Lecompte's owner to a rematch, held in 1855 in New Orleans and won by Lexington. Both of these horses were sons of Boston, a descendant of Sir Archy.<ref name=Montgomery152>Montgomery ''The Thoroughbred'' pp. 152–154</ref> Lexington went on to a career as a breeding stallion, and led the sires list of number of winners for sixteen years, fourteen of them in a row.<ref name=Wall119>Wall ''Famous Running Horses'' p. 119</ref>

After the [[American Civil War]], the emphasis in American racing changed from the older style of four-mile (6&nbsp;km) races in which the horses ran in at least two heats. The new style of racing involved shorter races not run in heats, over distances from five [[furlong]]s up to {{convert|1.5|mi}}. This development meant a change in breeding practices, as well as the age that horses were raced, with younger horses and sprinters coming to the fore. It was also after the Civil War that the American Thoroughbred returned to England to race. [[Iroquois (horse)|Iroquois]] became the first American-bred winner of the Epsom Derby in 1881. The success of American-bred Thoroughbreds in England led to the Jersey Act in 1913, which limited the importation of American Thoroughbreds into England.<ref name=Willett159>Willett ''The Thoroughbred'' pp. 159–163</ref> After [[World War I]], the breeders in America continued to emphasize speed and early racing age but also imported horses from England, and this trend continued past World War II.<ref name=Willett165>Willett ''The Thoroughbred'' pp. 165–171</ref> After [[World War II]], Thoroughbred breeding remained centered in Kentucky, but [[California]], New York, and [[Florida]] also emerged as important racing and breeding centers.<ref name=Willett175>Willett ''The Thoroughbred'' pp. 175–176</ref>

Thoroughbreds in the United States have historically been used not only for racing but also to improve other breeds. The early import Messenger was the foundation of the Standardbred,<ref name=Evans28>Evans ''The Horse'' pp. 28–29</ref> and Thoroughbred blood was also instrumental in the development of the [[American Quarter Horse]].<ref name=Evans23>Evans ''The Horse'' pp. 23–27</ref> The foundation stallion of the [[Morgan horse|Morgan]] breed is held by some to have been sired by a Thoroughbred.<ref name=Evans36>Evans ''The Horse'' p. 36</ref> Between World War I and World War II, the [[United States Army|U.S. Army]] used Thoroughbred stallions as part of their [[United States Army Remount Service|Remount Service]], which was designed to improve the stock of [[cavalry]] mounts.<ref name=Derry137>Derry ''Horses in Society'' pp. 136–137</ref><ref name=Fort27>Buecker ''Fort Robinson'' pp. 27–29</ref>

===In Europe===
Thoroughbreds began to be imported to France in 1817 and 1818 with the importation of a number of stallions from England, but initially the sport of horse racing did not prosper in France. The first Jockey Club in France was not formed until 1833, and in 1834 the racing and regulation functions were split off to a new society, the ''Société d'Encouragement pour l'Amélioration des Races de Chevaux en France'', better known as the [[Jockey-Club de Paris]].<ref name=Willett119>Willett ''The Thoroughbred'' pp. 119–122</ref> The ''French Stud Book'' was founded at the same time by the government.<ref name=Classic130>Willett ''The Classic Racehorse'' p. 30</ref> By 1876, French-bred Thoroughbreds were regularly winning races in England, and in that year a French breeder-owner earned the most money in England on the track.<ref name=Willett127>Willett ''The Thoroughbred'' pp. 125–128</ref> World War I almost destroyed French breeding because of war damage and lack of races.<ref name=Willett134>Willett ''The Thoroughbred'' p.134</ref> After the war, the premier French race, the Grand Prix, resumed and continues to this day. During [[World War II]], French Thoroughbred breeding did not suffer as it had during the first World War, and thus was able to compete on an equal footing with other countries after the war.<ref name=Willett139>Willett ''The Thoroughbred'' pp. 139–143</ref>

Organized racing in Italy started in 1837, when race meets were established in Florence and Naples and a meet in Milan was founded in 1842. Modern flat racing came to Rome in 1868. Later importations, including the Derby Stakes winners Ellington (1856) and Melton (1885), came to Italy before the end of the 19th&nbsp;century.<ref name=DerbyWins/><ref name=Willett180>Willett ''The Thoroughbred'' pp. 180–82</ref> Modern Thoroughbred breeding in Italy is mostly associated with the [[breeding program]] of [[Federico Tesio]], who started his breeding program in 1898. Tesio was the breeder of [[Nearco]], one of the dominant sires of Thoroughbreds in the later part of the 20th&nbsp;century.<ref name=Willett182>Willett ''The Thoroughbred'' pp. 182–187</ref>

Other countries in Europe have Thoroughbred breeding programs, including Germany,<ref name=Classic162>Willett ''The Classic Racehorse'' pp. 162–169</ref> Russia, Poland, and Hungary.<ref name=Classic202>Willett ''The Classic Racehorse'' pp. 202–211</ref>

===In Australia and New Zealand===
Horses arrived in Australia with the [[First Fleet]] in 1788 along with the earliest colonists.<ref name=Willett202>Willett ''The Thoroughbred'' pp. 202–205</ref> Although horses of part-Thoroughbred blood were imported into Australia during the late 18th century, it is thought that the first pureblood Thoroughbred was a stallion named Northumberland who was imported from England in 1802 as a [[Driving (horse)|coach horse]] sire.<ref name=Australia>{{cite web |url=http://www.tbheritage.com/TurfHallmarks/Aus/AusHistHerringer.html |title= Thoroughbred Horse Racing in Australia |access-date=2008-02-27 |author= Herringer, Philip|year= 2006|work= Turf Hallmarks|publisher= Thoroughbred Heritage}}</ref> By 1810, the first formal race meets were organized in Sydney, and by 1825 the first mare of proven Thoroughbred bloodlines arrived to join the Thoroughbred stallions already there.<ref name=Willett202/> In 1825, the [[Australian Turf Club|Sydney Turf Club]], the first true racing club in Australia, was formed. Throughout the 1830s, the Australian colonies began to import Thoroughbreds, almost exclusively for racing purposes, and to improve the local stock. Each colony formed its own racing clubs and held its own races.<ref name=Australia/> Gradually, the individual clubs were integrated into one overarching organization, now known as the [[Australian Racing Board]].<ref>{{cite web |url= http://www.tbheritage.com/Breeders/AUS/ASB.html|title= History of the Australian Stud Book: Part 1|access-date=2008-02-27 |author= Ford, Michael|date=June 2006|work= Breeders and Breeding|publisher= Thoroughbred Heritage}}</ref> Thoroughbreds from Australia were imported into New Zealand in the 1840s and 1850s, with the first direct importation from England occurring in 1862.<ref name=Willett213>Willett ''The Thoroughbred'' pp. 213–215</ref>

===In other areas===
Thoroughbreds have been exported to many other areas of the world since the breed was created. Oriental horses were imported into South Africa from the late 17th century in order to improve the local stock through crossbreeding. Horse racing was established there in the late 18th and early 19th centuries, and Thoroughbreds were imported in increasing numbers.<ref>{{cite web |url= http://www.tbheritage.com/Breeders/SABreeding/SABreeders.html|title= Thoroughbred Horse Racing and Breeding in South Africa|access-date=2008-02-27 |author=Herringer, Philip |year= 2004|work= Breeders and Breeding|publisher= Thoroughbred Heritage}}</ref> The first Thoroughbred stallions arrived in [[Argentina]] in 1853, but the first mares did not arrive until 1865. The Argentine Stud Book was first published in 1893.<ref name=Willett233>Willett ''The Thoroughbred'' pp. 233–235</ref> Thoroughbreds were imported into Japan from 1895, although it was not until after World War II that Japan began a serious breeding and racing business involving Thoroughbreds.<ref name=Willett238>Willett ''The Thoroughbred'' pp. 238–40</ref>

==Registration, breeding, and population==
{{Main|Thoroughbred breeding theories}}
{{See also|Horse breeding}}
[[File:Twilight20008-300.jpg|thumb|Twilight, the Thoroughbred mare who serves as the subject of the Equine Genome Project]]
The number of Thoroughbred [[foal]]s registered each year in North America varies greatly, chiefly linked to the success of the auction market which in turn depends on the state of the economy.<ref>{{cite news|last1=Wincze Hughes|first1=Alicia|title=Decline in Thoroughbred foal crop hurting racetracks while strengthening sales market|url=http://www.kentucky.com/sports/horses/article44508813.html|newspaper=Lexington Herald-Leader|access-date=29 September 2016}}</ref> The foal crop was over 44,000 in 1990, but declined to roughly 22,500 by 2014.<ref name=JCAbout>{{cite web |url= http://www.jockeyclub.com/default.asp?section=FB&area=2 |title= Annual North American Registered Foal Crop |access-date=2016-09-29 |author=The Jockey Club |work=The Jockey Club Website |publisher=The Jockey Club}}</ref> The largest numbers are registered in the states of Kentucky, Florida and California.<ref name=Factbook>{{cite web |url= http://www.jockeyclub.com/factbook.asp?section=4 |title= Distribution of Registered Foal US Foal Crop by State |access-date=2008-02-17 |author=The Jockey Club |date=c. 2007 |work=The Jockey Club Online Factbook |publisher=The Jockey Club}}</ref>{{refn|Note that some promotional materials from The Jockey Club state that there are slightly under 1.3&nbsp;million Thoroughbreds in the United States today registered with The Jockey Club,<ref>{{cite web |url= http://www.jockeyclub.com/pdfs/thoroughly_thoroughbred.pdf |title= Thoroughly Thoroughbred |access-date=2008-04-01 |author=The Jockey Club |work=The Jockey Club Website |publisher=The Jockey Club}}</ref> but combining this information with figures on foal registrations gives an average lifespan for registered Thoroughbreds of almost 35 years, which is well beyond normal for horses.|group=notes}} Australia is the second largest producer of Thoroughbreds in the world with almost 30,000&nbsp;broodmares producing about 18,250&nbsp;foals annually.<ref name="Racing Fact Book">{{cite web| url= http://australianracingboard.com.au/uploadimg/arb2010.pdf| title= Racing Fact Book| publisher= Australia Racing Board| page= 72| date= 2009–2010| access-date= 2010-12-03| archive-url= https://web.archive.org/web/20101214103139/http://www.australianracingboard.com.au/uploadimg/arb2010.pdf| archive-date= 2010-12-14|url-status=dead}}</ref> Britain produces about 5,000 foals a year,<ref>{{cite web|url= http://www.britishhorseracing.com/owning_breeding/breeding/3.2.3.asp|title= British Breeding: Overview|access-date= 2008-06-05|author= British Horseracing Authority|work= British Horseracing Authority Website|publisher= British Horseracing Authority|url-status=dead|archive-url= https://web.archive.org/web/20080509165347/http://www.britishhorseracing.com/owning_breeding/breeding/3.2.3.asp|archive-date= 2008-05-09}}</ref> and worldwide, there are more than 195,000&nbsp;active [[mare|broodmare]]s, or females being used for breeding, and 118,000&nbsp;newly registered foals in 2006 alone.<ref>{{cite web |url= http://www.jockeyclub.com/factbook.asp?section=17 |title= Thoroughbred Racing and Breeding Worldwide|access-date=2008-03-30 |author=The Jockey Club |work=The Jockey Club Website |publisher=The Jockey Club}}</ref> The Thoroughbred industry is a large [[agribusiness]], generating around $34&nbsp;billion in revenue annually in the United States and providing about 470,000&nbsp;jobs through a network of farms, training centers, and [[race track]]s.<ref name="NTRA">{{cite web |url= http://www.ntra.com/content/WTWG_final_report.pdf |title= Improving Security in the United States Pari-Mutuel Wagering System: Status Report and Recommendations |access-date=2008-02-17 |author= NTRA Wagering Technology Working Group in conjunction with Giuliani Partners LLC |date=August 2003 |work=National Thoroughbred Racing Association Web Site |publisher= National Thoroughbred Racing Association|archive-url = https://web.archive.org/web/20080228005111/http://www.ntra.com/content/WTWG_final_report.pdf  |archive-date = 2008-02-28}}</ref>

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'', the witnessed natural [[horse breeding|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.<ref>{{cite web |url= http://www.jockeyclub.com/registry.asp?section=3#one|title= Rules and Regulations of Thoroughbreds |access-date=2007-07-04 |publisher= The Jockey Club|work=The Jockey Club Website}}</ref> One reason is that a greater possibility of error exists in assigning parentage with artificial insemination, and although DNA and blood testing eliminate many of those concerns, artificial insemination still requires more detailed record keeping.<ref name=BreedMan349>Equine Research ''Breeding Management and Foal Development'' p. 349</ref> 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, although modern management still allows a stallion to live cover more mares in a season than was once thought possible. As an example, in 2008, the Australian stallion [[Encosta De Lago]] covered 227 mares.<ref name="studbook.org.au">[http://www.studbook.org.au/horse.aspx?hid=529224&pagetype=STALFERT Australian Stud Book: Encosta De Lago (AUS), Australian Jockey Club Limited and Victoria Racing Club Limited] Retrieved 2009-1-25</ref> By allowing a stallion to cover only a couple of hundred mares a year rather than the couple of thousand possible with artificial insemination, it also preserves the high prices paid for horses of the finest or most popular lineages.<ref name=HorseInfoFAQ>{{cite web |url= http://www.horseinfo.com/info/faqs/faqbreedingQ2.html |title= Frequently Asked Questions: Breeding |access-date=2008-02-17 |author= Russell Meerdink Co |work=HorseInfo.com Web Site |publisher= Russell Meerdink Co}}</ref>

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 [[allele]]s in the current population can be traced to 30&nbsp;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.<ref name="Cunningham"/> Thoroughbred pedigrees are generally traced through the [[Mother|maternal]] line, called the ''distaff'' line. The line that a horse comes from is a critical factor in determining the price for a young horse.<ref name="Napier">Napier ''Blood will tell'' pp. 17–18</ref>

==Value==
{{Main|Thoroughbred valuation}}
Prices of Thoroughbreds vary greatly, depending on age, [[Purebred|pedigree]], [[equine conformation|conformation]], and other market factors.<ref>{{cite web |url=http://extension.umd.edu/publications/PDFs/FS665.pdf |title=Price Factors and Sales Trends |access-date=2008-06-05 |work=Maryland Cooperative Extension |author=Commer, Malcolm |publisher=University of Maryland |archive-url=https://web.archive.org/web/20081031105044/http://extension.umd.edu/publications/PDFs/FS665.pdf |archive-date=2008-10-31}}</ref> In 2007, [[Keeneland Sales]], a United States-based sales company, sold 9,124 horses at auction, with a total value of $814,401,000, which gives an average price of $89,259.<ref name=Keeneland2007>{{cite web|url=http://ww2.keeneland.com/sales/lists/copy/recap.aspx|title=Yearly Sales Recap|access-date=2008-06-05|author=Keeneland Sales|work=Keeneland Sales Website|publisher=Keeneland Sales|url-status=dead|archive-url=https://web.archive.org/web/20080513173403/http://ww2.keeneland.com/sales/lists/copy/recap.aspx|archive-date=2008-05-13}}</ref> As a whole for the United States in 2007, The Jockey Club auction statistics indicated that the average [[weanling]] sold for $44,407, the average yearling sold for $55,300, average sale price for two-year-olds was $61,843, broodmares averaged $70,150, and horses over two and broodmare prospects sold for an average of $53,243.<ref>{{cite web |url=http://www.jockeyclub.com/factbook.asp?section=13 |title=2007 Auction Statistics |access-date=2008-06-05 |author=The Jockey Club |work=The Jockey Club Factbook |publisher=The Jockey Club}}</ref> For Europe, the July 2007 Tattersall's Sale sold 593 horses at auction, with a total for the sale of 10,951,300 [[Guinea (British coin)|guineas]],<ref>Traditionally, the obsolete guinea, £1.05, formerly 21 [[Shilling (United Kingdom)|shillings]], is retained as the unit of account for these sales.</ref> for an average of 18,468 guineas.<ref>{{cite web |url=https://www.tattersalls.com/sales/july-sale/4DCGI/Sale/JUL07/Main |title=Tattersall's July Sale 2007 |access-date=2008-06-05 |author=Tattersalls |work= Tattersall's Website |publisher=Tattersall's }}</ref> Also in 2007, Doncaster Bloodstock Sales, another British sales firm, sold 2,248 horses for a total value of 43,033,881 guineas, making an average of 15,110 guineas per horse.<ref>{{cite web |url=http://www.dbsauctions.com/news/SalesStatistics.htm |title=Sales Statistics |access-date=2008-06-05 |author=Doncaster Bloodstock Sales |work= Doncaster Bloodstock Sales Website |publisher= Doncaster Bloodstock Sales |archive-url = https://web.archive.org/web/20080317143123/http://www.dbsauctions.com/news/SalesStatistics.htm  |archive-date = 2008-03-17}}</ref> Australian prices at auction during the 2007–2008 racing and breeding season were as follows: 1,223 Australian weanlings sold for a total of $31,352,000, an average of $25,635 each. Four thousand, nine hundred and three yearlings sold for a total value of [[Australian dollar|A$]]372,003,961, an average of A$75,853. Five hundred two-year-olds sold for A$13,030,150, an average of A$26,060, and 2,118 broodmares totalled A$107,720,775, an average of A$50,860.<ref name=AUS2007>{{cite web|url=http://www.australianracingboard.com.au/uploadimg/arbFinalBook.pdf|title=Australian Sales Results|access-date=2010-01-18|author=Australian Racing Board Limited|work=Sales Website|publisher=Australian Racing Board Limited|archive-url=https://web.archive.org/web/20110220193606/http://www.australianracingboard.com.au/uploadimg/arbFinalBook.pdf|archive-date=2011-02-20|url-status=dead}}</ref>

Averages, however, can be deceiving. For example, at the 2007 Fall Yearling sale at Keeneland, 3,799 young horses sold for a total of $385,018,600, for an average of $101,347 per horse.<ref name=Keeneland2007/> However, that average sales price reflected a variation that included at least 19 horses that sold for only $1,000 each and 34 that sold for over $1,000,000 apiece.<ref>{{cite web |url=http://ww2.keeneland.com/sales/lists/sale/results.aspx?SaleId=200802 |title=Keeneland September 2007 Yearling Sale Results |access-date=2008-06-05 |author=Keeneland Sales |work=Keeneland Sales Website |publisher=Keeneland Sales |url-status=dead|archive-url=https://web.archive.org/web/20080125221957/http://ww2.keeneland.com/sales/lists/sale/results.aspx?SaleId=200802 |archive-date=2008-01-25 }}</ref>

The highest price paid at auction for a Thoroughbred was set in 2006 at $16,000,000 for a two-year-old colt named [[The Green Monkey]].<ref name="Green Monkey">{{cite web|url=http://www.bloodhorse.com/horse-racing/articles/43609/the-green-monkey-retired|title= The Green Monkey Retired|author=Biles, Deirdre |date=February 13, 2008 |access-date=December 19, 2009 |publisher=Bloodhorse.com}}</ref> Record prices at auction often grab headlines, though they do not necessarily reflect the animal's future success; in the case of The Green Monkey, injuries limited him to only three career starts before being retired to stud in 2008, and he never won a race.<ref name="Green Monkey"/> Conversely, even a highly successful Thoroughbred may be sold by the pound for a few hundred dollars to become [[horsemeat]]. The best-known example of this was the 1986 Kentucky Derby winner [[Ferdinand (horse)|Ferdinand]], exported to Japan to stand at stud, but was ultimately slaughtered in 2002, presumably for pet food.<ref>{{cite news|url=https://www.nytimes.com/2003/07/23/sports/horse-racing-1986-derby-winner-was-slaughtered-magazine-reports.html?pagewanted=1 |author=Finley, Bill |title=Horse Racing; 1986 Derby Winner Was Slaughtered, Magazine Reports |date=2003-07-23 |newspaper =New York Times |access-date= 2009-12-28}}</ref>

However, the value of a Thoroughbred may also be influenced by the purse money it wins. In 2007, Thoroughbred racehorses earned a total of $1,217,854,602 in all placings, an average earnings per starter of $16,924.<ref name=RacingStats>{{cite web |url=http://www.jockeyclub.com/factbook.asp?section=9 |title=2007 Racing Statistics |access-date=2008-06-05 |author=The Jockey Club |work=The Jockey Club Factbook |publisher=The Jockey Club}}</ref> In addition, the track record of a race horse may influence its future value as a breeding animal.

Stud fees for stallions that enter breeding can range from $2,500 to $500,000 per mare in the United States,<ref>{{cite web |url=http://breeding.bloodhorse.com/sirelists/national08/leading_sire.asp |title=2008 Leading Sires |access-date=2008-06-05 |magazine=[[The Blood-Horse magazine]] |url-status=dead|archive-url=https://web.archive.org/web/20080613203823/http://breeding.bloodhorse.com/sirelists/national08/leading_sire.asp |archive-date=2008-06-13}}</ref><ref>{{cite web|url= http://www.bloodhorse.com/horse-racing/articles/5756/storm-cat-stud-fee-rises-to-500000|author=Liebman, Dan |title=Storm Cat Stud Fee Rises to $500,000|work=The Blood-Horse magazine|access-date=December 29, 2009|date=March 6, 2002}}</ref> and from £2000<ref>{{cite web |url=http://www.oracle.racingadmin.co.uk/pls/production/osts201 |title= Stud Advertisement for Desideratum |access-date=2008-06-05 |author=Weatherby's |work=Weatherby's Online Stallion Book |publisher=Weatherby's}}</ref> to £75,000 or more in Britain.<ref>{{cite web |url=http://www.oracle.racingadmin.co.uk/pls/production/osts201 |title= Stud Advertisement for Dansili |access-date=2008-06-05 |author=Weatherby's |work=Weatherby's Online Stallion Book |publisher=Weatherby's}}</ref> The record stud fee to date was set in the 1980s, when the stud fee of the late [[Northern Dancer]] reached $1 million.<ref>{{cite news|url=https://www.nytimes.com/1990/11/17/sports/horse-racing-northern-dancer-one-of-racing-s-great-sires-is-dead.html|author=Thomas, Robert|title= Northern Dancer, One of Racing's Great Sires, Is Dead |work=[[The New York Times]]|date=November 17, 1990}}</ref> During the 2008 Australian breeding season seven stallions stood at a stud fee of A$110,000 or more, with the highest fee in the nation at A$302,500.<ref name="studbook.org.au"/>

==Uses==
[[File:Horse-racing-4.jpg|left|thumb|Race horses competing on turf (grass racetrack) in Germany. Most races in Europe are run on turf, while most races in North America are run on dirt. |alt=Two horses racing along a grass racetrack, the horses are side by side with both jockeys urging the horses faster.]]
Although the Thoroughbred is primarily bred for [[Thoroughbred horse race|racing]], the breed is also used for [[show jumping]] and [[eventing|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===
{{Main|Thoroughbred horse race}}

Thoroughbred horses are primarily bred for racing under [[saddle]] at the [[horse gait|gallop]]. Thoroughbreds are often known for being either distance runners or sprinters, and their [[Equine conformation|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.<ref name=TrackTalk26>Phifer ''Track Talk'' p. 26</ref> The size of the horse is one consideration for buyers and trainers when choosing a potential racehorse. Although there have been champion racehorses of every height, from [[Zenyatta]] who stood 17.2 hands,<ref name=Zenyatta>{{cite news |url=http://www.kentucky.com/2010/10/31/1501800/large-and-in-charge-the-zenyatta.html |title=Large and in charge: The Zenyatta file |newspaper=[[Lexington Herald-Leader]] |date=October 31, 2010 |access-date=July 9, 2012 |archive-date=November 7, 2012 |archive-url=https://web.archive.org/web/20121107113546/http://www.kentucky.com/2010/10/31/1501800/large-and-in-charge-the-zenyatta.html |url-status=dead }}</ref> to [[Man o' War]] and [[Secretariat (horse)|Secretariat]] who both stood at 16.2 hands,<ref name=Montgomery183>Montgomery ''The Thoroughbred'' pp. 183–186</ref><ref name=Bong112>Bongianni ''Champion Horses'' pp. 112–113</ref> down to [[Hyperion (horse)|Hyperion]], who was only 15.1,<ref name=Bong56>Bongianni ''Champion Horses'' p. 56</ref> the best racehorses are generally of average size.<ref name="Wagoner">Hedge ''Horse Conformation'' p. 35</ref> Larger horses mature more slowly and have more stress on their legs and feet, predisposing them to lameness.<ref name="Equus">Barakat "Why Size Matters" ''Equus''</ref> 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.<ref name="Wagoner"/> Historically, Thoroughbreds have steadily increased in size: the average height of a Thoroughbred in 1700 was about 13.3&nbsp;hands high. By 1876 this had increased to 15.3.<ref name=TrackTalk24>Phifer ''Track Talk'' p. 24</ref>

In 2007, there were 71,959 horses who started in races in the United States, and the average Thoroughbred racehorse in the United States and Canada ran 6.33 times in that year.<ref name=RacingStats/> In Australia, there were 31,416 horses in training during 2007, and those horses started 194,066 times for [[A$]]375,512,579 of prize money. During 2007, in Japan, there were 23,859 horses in training and those horses started 182,614 times for [[A$]]857,446,268 of prize money.<ref name="Racing Fact Book"/> 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.<ref>{{cite web |url=http://www.britishhorseracing.com/images/inside_horseracing/media/BHA_Annual_Review_06-07.pdf |title=British Horseracing Review 2006–2007 |access-date=2008-06-05 |author=British Horseracing Authority |work=British Horseracing Authority Website |publisher=British Horseracing Authority |url-status=dead|archive-url=https://web.archive.org/web/20081031105044/http://www.britishhorseracing.com/images/inside_horseracing/media/BHA_Annual_Review_06-07.pdf |archive-date=2008-10-31 }}</ref>

Statistically, fewer than 50% of all race horses ever win a race, and less than 1% ever win a [[Graded stakes race|stakes race]] such as the [[Kentucky Derby]] or [[Epsom Derby]].<ref>{{cite journal |url=http://www.businessweek.com/magazine/content/03_24/b3837115_mz025.htm?chan=search |archive-url=https://web.archive.org/web/20090415151446/http://www.businessweek.com/magazine/content/03_24/b3837115_mz025.htm?chan=search |url-status=dead |archive-date=April 15, 2009 |title=So You Want to Race a Horse |access-date=2008-06-05 |author=Gutner, Toddi |date=2003-06-16 |journal= [[Business Week]]| publisher= Business Week |page= 92}}</ref> Any horse who has yet to win a race is known as a maiden.

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.<ref>{{cite journal |url=http://www.bloodhorse.com/TradeZone/pdf/tz_05-10-08.pdf |title= Options for Ex-racehorses |access-date=2008-06-05 |last= Thomas |first=Heather Smith |date=2008-05-10 |journal=The Blood-Horse Magazine}}</ref>

===Other disciplines===
[[File:R3DE XCountry.JPG|right|thumb|A Thoroughbred competing in [[eventing]]|alt=A horse just taking off from the ground to jump a wooden jump. The horse's back legs are still on the ground but its two front legs are stretched forward and upward to reach over the jump. The rider is flat against the horse's neck.]]
In addition to racing, Thoroughbreds compete in [[eventing]], [[show jumping]] and [[dressage]] at the highest levels of international competition, including the [[Equestrian at the Summer Olympics|Olympics]]. They are also used as [[show hunter]]s, [[Steeplechase (horse racing)|steeplechase]]rs, and in [[Western riding]] speed events such as [[Barrel Racing|barrel racing]]. [[Mounted police]] divisions employ them in non-competitive work, and recreational riders also use them.<ref name=JCTBinfo>{{cite web |url= http://www.jockeyclub.com/thoroughbredHistory.asp |title= The Thoroughbred |access-date=2008-02-17 |archive-url =https://web.archive.org/web/20130703080541/http://www.jockeyclub.com/thoroughbredHistory.asp |archive-date=2013-07-03 |author=The Jockey Club |work= The Jockey Club Web Site |publisher=The Jockey Club}}</ref> Thoroughbreds are one of the most common breeds for use in [[polo]] in the United States.<ref>{{cite web |url=http://www.americanpolohorse.com/polohorse.html |title=What is a Polo Pony or Polo Horse? |access-date=2012-03-30 |author=American Polo Horse Association staff |work=American Polo Horse Association Web Site |publisher=American Polo Horse Association |archive-url=https://web.archive.org/web/20070812004017/http://www.americanpolohorse.com/polohorse.html |archive-date=2007-08-12 |url-status=dead}}</ref> They are often seen in the [[fox hunting]] field as well.<ref>Jones "Fox Hunting in America" ''American Heritage Magazine''</ref>

===Crossbreeding===
Thoroughbreds are often crossed with horses of other breeds to create new breeds or to enhance or introduce specific qualities into existing ones. They have been influential on many modern [[riding horse]] breeds, such as the [[American Quarter Horse]],<ref name=OKStateQH>{{cite web |url= http://www.ansi.okstate.edu/breeds/horses/quarter |title= Quarter Horse |access-date=2008-02-17 |author=Oklahoma State University Department of Animal Science |work=Breeds of Livestock |publisher= Oklahoma State University}}</ref> the [[Standardbred horse|Standardbred]],<ref name=OKStateStandardbred>{{cite web |url= http://www.ansi.okstate.edu/breeds/horses/standardbred/index.htm |title= Standardbred |access-date= 2008-02-17 |author= Oklahoma State University Department of Animal Science |work= Breeds of Livestock |publisher= Oklahoma State University |url-status=dead|archive-url= https://web.archive.org/web/20071208080247/http://www.ansi.okstate.edu/breeds/horses/standardbred/index.htm |archive-date= 2007-12-08 }}</ref> and possibly the [[Morgan horse|Morgan]], a breed that went on to influence many of the [[ambling|gaited]] breeds in North America.<ref name=MorganMus>{{cite web |url= http://www.morganmuseum.org/html/amhistory.html |title= Morgan Horses in American History |access-date=2008-02-17 |author= Curler, Elizabeth |work= The National Museum of the Morgan Horse Web Site |publisher= The National Museum of the Morgan Horse}}</ref> Other common crosses with the Thoroughbred include crossbreeding with Arabian bloodlines to produce the [[Anglo-Arabian]]<ref>{{cite web|url= http://www.arabianhorses.org/registration/hareg/reg_haquick_facts.asp|title= Quick Facts|access-date= 2008-02-27|work= Half-Arabian and Anglo-Arabian Registration|publisher= Arabian Horse Association|url-status=dead|archive-url= https://web.archive.org/web/20080612164635/http://www.arabianhorses.org/registration/hareg/reg_haquick_facts.asp|archive-date= 2008-06-12}}</ref> as well as with the [[Irish Draught]] to produce the [[Irish Sport Horse]].<ref name=ISH>{{cite web |url= http://www.irishdraught.com/aboutsh |title= The Irish Draught Sport Horse |access-date=2008-02-17 |author= Irish Draught Horse Society |work= Irish Draught Horse Society Web Site |publisher= Irish Draught Horse Society}}</ref>

Thoroughbreds have been [[foundation bloodstock]] for various [[Warmblood]] breeds due to their refinement and performance capabilities.<ref>{{cite web|url= http://www.americantrakehner.com/The%20Breed/TBInfluence.htm|title= The Trakehner Breed and the Thoroughbred|access-date= 2008-02-27|author= Von Velsen, Eberhard|date= September–October 1981|work= Trakehner Hefte|publisher= American Trakehner Association|url-status=dead|archive-url= https://web.archive.org/web/20080220234139/http://www.americantrakehner.com/The%20Breed/TBInfluence.htm|archive-date= 2008-02-20}}</ref> Crossbred horses developed from Thoroughbreds, (informally categorized as "hot bloods" because of temperament) crossed on sturdy [[draft horse]] breeds, (classified as "cold bloods" for their more phlegmatic temperament) are known as "warmbloods," which today are commonly seen in competitive events such as show jumping and dressage.<ref>{{Cite web |date=2014-06-17 |title=Hot Blood, Warm Blood, Cold Blood in Horses |url=https://ker.com/equinews/hot-blood-warm-blood-cold-blood-horses/ |access-date=2022-12-31 |website=Kentucky Equine Research}}</ref><ref>{{Cite web |date=2020-12-05 |title=Why Are Some Horses Called Warmbloods? Definition & Breeds. |url=https://horseracingsense.com/why-horses-called-warmbloods-definition-breed/ |access-date=2022-12-31}}</ref><ref>{{Cite web |title="Warmblood" Is Not a Breed |url=https://horsesport.com/magazine/breeding/warmblood-is-not-a-breed/ |access-date=2022-12-31 |website=Horse Sport|date=July 24, 2012 }}</ref> Examples include the [[Dutch Warmblood]], [[Hanoverian horse|Hanoverian]], and [[Selle Français]].<ref>{{Cite web |title=Warmblood |url=https://horse-canada.com/breeds/warmblood/ |access-date=2022-12-31 |website=Horse Canada |language=en-CA}}</ref> Some warmblood registries note the percentage of Thoroughbred breeding, and many warmblood breeds have an [[open stud book]] that continues to allow Thoroughbred crossbreeding.<ref>{{Cite web |title=HorseTelex |url=https://www.horsetelex.com/ |access-date=2022-12-31 |website=HorseTelex |language=nl}}</ref>

==Health issues==
Although Thoroughbreds are seen in the [[hunt seat|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.<ref name="Pickrell"/> 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.<ref name="WP">Rosenblatt [https://www.washingtonpost.com/wp-dyn/content/article/2007/04/23/AR2007042301231.html "Barbaro's Legacy"] ''Washington Post''</ref> Other countries report lower rates of injury, with the United Kingdom having 0.9 injuries/1,000 starts (1990–1999) and the courses in [[Victoria (Australia)|Victoria, Australia]], producing a rate of 0.44 injuries/1,000 starts (1989–2004).<ref name=UPCI>Oke, "Understanding and Preventing Catastrophic Injuries", ''The Horse'', 26–36.</ref> 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.<ref name="Pickrell"/> 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,<ref name="ppt">{{cite web |url= http://www.grayson-jockeyclub.org/newsimages/toe_grabs.ppt |title= The Detrimental Effects of Toe Grabs |format=ppt |author= Casner, Bill |date=April 2007 |access-date=2008-02-17}}</ref> which contributes to foot soreness, the most common source of lameness in racehorses.<ref>Arthur ''Diagnosis and Management of Lameness in the Horse'' p. 872</ref>

===Selective breeding===
One argument for the health issues involving Thoroughbreds suggests that [[inbreeding]] is the culprit.<ref name="Pickrell"/> 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 racing|horse races]].<ref name=Kluger>Kluger "Bred for Speed...Built for Trouble" ''Time Magazine''</ref> Thus, according to one postulation, the modern Thoroughbred travels faster than its skeletal structure can support.<ref name=Finley>Finley "Sadly, No Way to Stop Deaths" ''New York Daily News''</ref> Veterinarian [[Robert M. Miller]] states that "We have selectively bred for speeds that the anatomy of the horse cannot always cope with."<ref name="Miller">Miller [http://www.equine-reproduction.com/articles/Horse-Lovers.shtml "And They Call Us Horse Lovers"] ''Cowboy Magazine''</ref>

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 [[equine conformation|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.<ref name=UPCI/>

===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.<ref name="Miller"/> However, catastrophic injury rates are higher in 4- and 5-year-olds than in 2- and 3-year-olds.<ref>Bourke "Fatalities on racecourses in Victoria" ''Proceedings of the 10th International Conference of Racing Analysts and Veterinarians''</ref> 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.<ref name=UPCI/>

Studies have shown that track surfaces,<ref>Oikawa "Effect of restructuring of a racetrack on the occurrence of racing injuries in thoroughbred horses" ''Journal of Equine Veterinary Science''</ref> [[horseshoe]]s with toe grabs,<ref name="ppt"/> use of certain legal medications,<ref name=PETA>{{cite web |url= http://www.peta.org/mc/factsheet_display.asp?ID=65 |title= The Horseracing Industry: Drugs, Deception and Death |access-date= 2008-02-17 |author= PETA |work= PETA Media Center |publisher= People for the Ethical Treatment of Animals |url-status=dead|archive-url= https://web.archive.org/web/20080306053641/http://www.peta.org/mc/factsheet_display.asp?ID=65 |archive-date= 2008-03-06 }}</ref> and high-intensity racing schedules may also contribute to a high injury rate.<ref name=USAToday>Pedulla [https://www.usatoday.com/sports/horses/triple/2006-06-04-triple-crown-scrutiny_x.htm "Injury steps up scrutiny on Triple Crown Schedule"] ''USA Today''</ref> One promising trend is the development of synthetic surfaces for racetracks, and one of the first tracks to install such a surface, [[Turfway Park]] in [[Florence, Kentucky]], saw its rate of fatal breakdowns drop from 24 in 2004–05 to three in the year following Polytrack installation. The material is not perfected, and some areas report problems related to winter weather, but studies are continuing.<ref name="WP"/>

===Medical challenges===
The level of treatment given to injured Thoroughbreds is often more intensive than for horses of lesser financial value<ref name=BaltSun>Walker [http://www.baltimoresun.com/sports/bal-te.sp.racing30jan30,0,3354975.story "Barbaro's injury highlighted problems, medical advances"] {{Webarchive|url=https://web.archive.org/web/20081011125313/http://www.baltimoresun.com/sports/bal-te.sp.racing30jan30,0,3354975.story |date=October 11, 2008 }} ''Baltimore Sun''</ref> but also controversial, due in part to the significant challenges in treating broken bones and other major leg injuries.<ref name="NYT">Grady [https://www.nytimes.com/2006/05/23/sports/othersports/23leg.html?pagewanted=1&_r=2 "State of the Art to Save Barbaro"] ''The New York Times''</ref> 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 system of the horse|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, internal damage, and congestion.<ref name="NYT"/>

Whenever a racing accident severely injures a well-known horse, such as the major leg fractures that led to the [[animal euthanasia|euthanization]] of 2006 [[Kentucky Derby]] winner [[Barbaro (horse)|Barbaro]], or 2008 Kentucky Derby runner-up [[Eight Belles]], [[animal rights]] groups have denounced the Thoroughbred racing industry.<ref name=PETABarbaro>{{cite web |url=http://www.peta.org/campaigns/barbaro.asp |title=Barbaro's Tragic Injury: A Symptom of a Cruel Industry |access-date=2008-02-17 |author=PETA |work=PETA.org Campaigns |publisher=People for the Ethical Treatment of Animals |url-status=dead|archive-url=https://web.archive.org/web/20080209235419/http://www.peta.org/campaigns/barbaro.asp |archive-date=2008-02-09 }}</ref> 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.<ref name=HBLB>{{cite web |url= http://www.hblb.org.uk/document.php?id=14 |title= Advancing Veterinary Science and Education |access-date= 2008-02-17 |author= Horserace Levy Betting Board staff |work= Horserace Levy Betting Board Web Site |publisher= Horserace Levy Betting Board |url-status=dead|archive-url= https://web.archive.org/web/20071102185610/http://www.hblb.org.uk/document.php?id=14 |archive-date= 2007-11-02}}</ref> Although horse racing is hazardous, veterinary science has advanced. Previously hopeless cases can now be treated,<ref name="NYT"/> and earlier detection through advanced imaging techniques like [[Nuclear medicine|scintigraphy]] can keep at-risk horses off the track.<ref>Mackey "Stress fractures of the humerus, radius and tibia in horses" ''Veterinary Radiology''</ref>

==See also==
* [[Thoroughbred breeding theories]]
* [[Glossary of North American horse racing]]
* [[Thoroughbred racing in Australia]]
* [[Thoroughbred racing in New Zealand]]
* [[List of leading Thoroughbred racehorses]]
* [[List of historical horses]]

==Notes==
{{Reflist|group=notes}}

==Footnotes==
{{Reflist|colwidth=30em}}

==References==
{{refbegin|colwidth=60em}}
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* {{cite journal |author= Grady, Denise |date= 23 May 2006 |title= State of the Art to Save Barbaro |journal= The New York Times |url= https://www.nytimes.com/2006/05/23/sports/othersports/23leg.html?pagewanted=1&_r=2 |access-date= 2008-02-17 }}
* {{cite book | last = Hedge | first = Juliet |author2=Don M. Wagoner | title = Horse Conformation: Structure, Soundness and Performance | publisher = Globe Pequot | year = 2004 | isbn = 1-59228-487-6}}
* {{cite book |title=All About Horses |author=Henry, Marguerite |year=1967 |publisher=Random House |isbn=0-394-80243-8 |url=https://archive.org/details/allabouthorses0000henr }}
* {{cite journal |author= Jones, Caroline |date=October 1973 |title= Fox Hunting in America |journal= American Heritage Magazine |volume=24 |issue=6 }}
* {{cite journal |author= Kluger, Jeffrey |date= 28 May 2006 |title= Bred for Speed...Built for Trouble |journal= Time Magazine |url= http://www.time.com/time/magazine/article/0,9171,1198889-1,00.html |archive-url= https://web.archive.org/web/20080406043215/http://www.time.com/time/magazine/article/0,9171,1198889-1,00.html |url-status= dead |archive-date= April 6, 2008 |access-date= 2008-02-17 }}
* {{cite journal |doi=10.1111/j.1740-8261.1987.tb01719.x |title=Stress fractures of the humerus, radius, and tibia in horses: clinical features and radiographic and/or scintigraphic appearance |year=1987 |last1=MacKey |first1=Valorie S. |last2=Trout |first2=Donald R. |last3=Meagher |first3=Dennis M. |last4=Hornof |first4=William J. |journal=Veterinary Radiology & Ultrasound |volume=28 |issue=1 |pages=26–31}}
* {{cite book |title=The Merriam-Webster Dictionary of English Usage |url=https://archive.org/details/merriamwebsterd00merr |url-access=registration |author=Merriam-Webster |year=1989 |publisher=Merriam-Webster |location=Springfield, MA |isbn=0-87779-132-5 }}
* {{cite journal |author= Miller, Robert M. |date= Fall 2006 |title= And They Call Us Horse Lovers |journal= Cowboy Magazine |url= http://www.equine-reproduction.com/articles/Horse-Lovers.shtml |access-date= 2008-02-17 }}
* {{cite book |title=The Godolphin Arabian: The Story of the Matchem Line |last=Milner |first=Mordaunt |year=1990 |publisher=J. A. Allen |location=London |isbn=0-85131-476-7}}
* {{cite book |author=Montgomery, Edward E. |title=The Thoroughbred |publisher=Arco Publishing |location=New York |year=1971 |isbn=0-668-02824-6 |url-access=registration |url=https://archive.org/details/thoroughbred0000mont }}
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* {{cite book |title=The Turf |author=Nimrod |publisher=Gay and Bird |location=London |year=1901}}
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* {{cite book |title=Track Talk: An Introduction to Thoroughbred Racing |last=Phifer |first=Kate Gilbert |year=1978 |publisher=Robert B. Luce Co. |location=Washington, D.C. |isbn=0-88331-098-8 |url=https://archive.org/details/tracktalkintrodu00phif }}
* {{cite web |url= https://www.newscientist.com/article/dn7941-95-of-thoroughbreds-linked-to-one-superstud/ |title= 95% of thoroughbreds linked to one superstud |access-date= 2008-02-17 |author= Pickrell, John |date= September 2005 |work= NewScientist.com news service |publisher= New Scientist }}
* {{cite book | last = Robertson | first = William P. | title = The History of Thoroughbred Racing in America | publisher = Bonanza Books | year = 1964 | location = New York |oclc=1028160}}
* {{cite news |author= Rosenblatt, Richard |title= Barbaro's Legacy: Better Life for Horses |url= https://www.washingtonpost.com/wp-dyn/content/article/2007/04/23/AR2007042301231.html |newspaper= Washington Post |date= 2007-04-23 |access-date= 2008-02-17 }}
* {{cite journal |author1=Walker, Childs |author2=Bill Ordine |name-list-style=amp |date=30 January 2007 |title=Barbaro's injury highlighted problems, medical advances |journal=Baltimore Sun |url=http://www.baltimoresun.com/sports/bal-te.sp.racing30jan30,0,3354975.story |access-date=2008-02-17 |archive-date=October 11, 2008 |archive-url=https://web.archive.org/web/20081011125313/http://www.baltimoresun.com/sports/bal-te.sp.racing30jan30,0,3354975.story |url-status=dead }}
* {{cite book |title=Famous Running Horses: Their Forebears and Descendants |last=Wall |first=John F. |year=1949 |publisher=Infantry Journal Press |location= Washington, DC |edition= Reprint edition from Kessinger Publishing (2007) |isbn=1-4325-9386-2}}
* {{cite book |author=Willett, Peter |title=The Classic Racehorse |publisher=University Press of Kentucky |location=Lexington, KY |year=1982 |isbn=0-8131-1477-2}}
* {{cite book |title= The Thoroughbred |url= https://archive.org/details/thoroughbred0000will |url-access= registration |last= Willett |first= Peter |year= 1970 |publisher= G. P. Putnam's Sons |location= New York |isbn= 0-297-00225-2 }}
{{refend}}

==External links==
{{commons+cat}}
{{Wiktionary|Thoroughbred|thoroughbred}}
* [http://www.thejockeyclub.co.uk/ Jockey Club (UK)]
* [http://www.jockeyclub.com/ The Jockey Club (USA)]
* [http://www.bloodlines.net/TB/ Thoroughbred Bloodlines]
* [http://www.studbook.org.au/ Australian Stud Book]
* [http://myracing.com/royal-ascot-ancestry/ Royal Ascot Bloodline Interactive Tool]

[[Category:Horse breeds originating in England]]
[[Category:Horse breeds]]
[[Category:Horse racing]]
[[Category:Thoroughbred horses]]
[[Category:Contexts for auctions]]

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Symbols: ~ | ¡ ¿ † ‡ ↔ ↑ ↓ • ¶ # ∞ ‹› «» ¤ ₳ ฿ ₵ ¢ ₡ ₢ $ ₫ ₯ € ₠ ₣ ƒ ₴ ₭ ₤ ℳ ₥ ₦ № ₧ ₰ £ ៛ ₨ ₪ ৳ ₮ ₩ ¥ ♠ ♣ ♥ ♦ 𝄫 ♭ ♮ ♯ 𝄪 © ® ™
Latin: A a Á á À à Â â Ä ä Ǎ ǎ Ă ă Ā ā Ã ã Å å Ą ą Æ æ Ǣ ǣ B b C c Ć ć Ċ ċ Ĉ ĉ Č č Ç ç D d Ď ď Đ đ Ḍ ḍ Ð ð E e É é È è Ė ė Ê ê Ë ë Ě ě Ĕ ĕ Ē ē Ẽ ẽ Ę ę Ẹ ẹ Ɛ ɛ Ǝ ǝ Ə ə F f G g Ġ ġ Ĝ ĝ Ğ ğ Ģ ģ H h Ĥ ĥ Ħ ħ Ḥ ḥ I i İ ı Í í Ì ì Î î Ï ï Ǐ ǐ Ĭ ĭ Ī ī Ĩ ĩ Į į Ị ị J j Ĵ ĵ K k Ķ ķ L l Ĺ ĺ Ŀ ŀ Ľ ľ Ļ ļ Ł ł Ḷ ḷ Ḹ ḹ M m Ṃ ṃ N n Ń ń Ň ň Ñ ñ Ņ ņ Ṇ ṇ Ŋ ŋ O o Ó ó Ò ò Ô ô Ö ö Ǒ ǒ Ŏ ŏ Ō ō Õ õ Ǫ ǫ Ọ ọ Ő ő Ø ø Œ œ Ɔ ɔ P p Q q R r Ŕ ŕ Ř ř Ŗ ŗ Ṛ ṛ Ṝ ṝ S s Ś ś Ŝ ŝ Š š Ş ş Ș ș Ṣ ṣ ß T t Ť ť Ţ ţ Ț ț Ṭ ṭ Þ þ U u Ú ú Ù ù Û û Ü ü Ǔ ǔ Ŭ ŭ Ū ū Ũ ũ Ů ů Ų ų Ụ ụ Ű ű Ǘ ǘ Ǜ ǜ Ǚ ǚ Ǖ ǖ V v W w Ŵ ŵ X x Y y Ý ý Ŷ ŷ Ÿ ÿ Ỹ ỹ Ȳ ȳ Z z Ź ź Ż ż Ž ž ß Ð ð Þ þ Ŋ ŋ Ə ə
Greek: Ά ά Έ έ Ή ή Ί ί Ό ό Ύ ύ Ώ ώ Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ Φ φ Χ χ Ψ ψ Ω ω {{Polytonic|}}
Cyrillic: А а Б б В в Г г Ґ ґ Ѓ ѓ Д д Ђ ђ Е е Ё ё Є є Ж ж З з Ѕ ѕ И и І і Ї ї Й й Ј ј К к Ќ ќ Л л Љ љ М м Н н Њ њ О о П п Р р С с Т т Ћ ћ У у Ў ў Ф ф Х х Ц ц Ч ч Џ џ Ш ш Щ щ Ъ ъ Ы ы Ь ь Э э Ю ю Я я ́
IPA: t̪ d̪ ʈ ɖ ɟ ɡ ɢ ʡ ʔ ɸ β θ ð ʃ ʒ ɕ ʑ ʂ ʐ ç ʝ ɣ χ ʁ ħ ʕ ʜ ʢ ɦ ɱ ɳ ɲ ŋ ɴ ʋ ɹ ɻ ɰ ʙ ⱱ ʀ ɾ ɽ ɫ ɬ ɮ ɺ ɭ ʎ ʟ ɥ ʍ ɧ ʼ ɓ ɗ ʄ ɠ ʛ ʘ ǀ ǃ ǂ ǁ ɨ ʉ ɯ ɪ ʏ ʊ ø ɘ ɵ ɤ ə ɚ ɛ œ ɜ ɝ ɞ ʌ ɔ æ ɐ ɶ ɑ ɒ ʰ ʱ ʷ ʲ ˠ ˤ ⁿ ˡ ˈ ˌ ː ˑ ̪ {{IPA|}}

Wikidata entities used in this page

Thoroughbred: Sitelink, Title, Some statements, Description: en, Miscellaneous (e.g. aliases, entity existence)
Category:Thoroughbred racehorses: Sitelink

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