Thoroughbred

About the breed

The Thoroughbred (Equus ferus caballus), also called the English Thoroughbred, is a racing breed developed in England and now bred worldwide, above all for flat racing. It is a tall, lean, fast horse with a long, sloping shoulder, thin skin and fine but hard legs. The Slovenian breeding programme gives a height at the withers of 155–165 cm for stallions and mares, and published measurements put mature racehorses at a usual 400–600 kg. Beyond the racecourse it is seen in show jumping, eventing and dressage, and breeders have used it for centuries to improve other breeds.

Three Eastern stallions and the first stud book

The Thoroughbred was created by crossing native stock with imported horses of Eastern origin. The Slovenian breeding programme lists Arabian, Barb, Turkish and Persian horses alongside native stock as its ancestors, and says crossbreeding stopped in the mid-18th century, since when the breed has been bred pure. Three stallions brought to England between 1689 and about 1730 are regarded as its foundation sires: the Byerley Turk, the Darley Arabian and the Godolphin Arabian (also called the Godolphin Barb). The Arabian Horse Association (AHA) writes that most modern Thoroughbreds can be traced back to these three; the sources give slightly different years for their arrival.

The stud book is what fixed the breed. According to Encyclopaedia Britannica, the General Stud Book admitted only horses that traced in direct line to the so-called Royal Mares (43 mares imported under James I and Charles I) or to the three stallions. Weatherbys, the family firm that still publishes it, dates the first General Stud Book to 1791, while the Slovenian programme places the first volume in 1793. By modern standards the early pedigrees were not detailed: the book was at first mainly a way of proving a horse's identity so that it ran in the right races.

What makes a horse a Thoroughbred

A Thoroughbred is a horse registered in a stud book recognised by the International Stud Book Committee (ISBC). The word therefore does not mean any purebred horse, even though, as Britannica points out, it is sometimes misused that way. A horse with only one Thoroughbred parent is called a half-bred in Britain and a grade Thoroughbred in the United States.

The breeding rules are strict. Under the Slovenian breeding programme the breed is bred only pure, natural cover is the only permitted method, and artificial insemination, embryo transfer and cloning are not allowed. The covering season runs from 15 February to 15 August. As a result every registered Thoroughbred's pedigree is recorded in a recognised stud book.

The Thoroughbred in Slovenia

Thoroughbreds have been bred in Slovenia since 1993, and the Slovenian stud book gained international recognition in 2000. The breeding programme is run by the Veterinary Faculty in Ljubljana. The population is small: for 2009 the programme lists 186 horses, including 82 breeding mares and 12 breeding stallions, and does not expect much growth until the country has a suitable racecourse.

The Slovenian breeding goal is a harmonious, elegant and noble horse of kind character and lively temperament, with correct and ground-covering paces, suited to flat racing as well as other equestrian sports.

Height, weight and build

The Slovenian breeding programme gives a height at the withers of 155–165 cm for stallions and mares. To enter the first stallion book a stallion must measure at least 160 cm, and a mare needs at least 155 cm for the main mare book. Britannica gives an average of about 163 cm and a wider range of 15 to 17 hands (roughly 152–173 cm), so individual horses can be noticeably taller or shorter than the Slovenian frame.

The stud book does not set a weight. A Japanese study in the Journal of Equine Science states that mature Thoroughbred racehorses generally weigh 400–600 kg, and Britannica gives a typical figure of about 450 kg.

The breeding programme describes a small to medium, clean-cut head with a broad forehead and large dark eyes, a long arched neck, long pronounced withers, a long sloping shoulder and short cannons with hard, well-shaped hooves. Britannica adds thin skin and fine-boned legs, and notes that short leg bones allow a long, easy stride.

Colours: usual and permitted

According to Britannica, Thoroughbreds are usually bay, chestnut, brown, black or grey. The Slovenian breeding programme allows all colours. The Jockey Club in the United States recognises bay, dark bay or brown, chestnut, black, grey or roan (a single combined category), palomino and white. Colour is also part of identification: under the Slovenian rules a foal's registration can be refused if its colour does not match that of its parents.

Temperament: sensitive, spirited and willing

The Thoroughbred is a sensitive, spirited and willing horse that reacts quickly to its surroundings and to its rider. Britannica describes it as sensitive and high-spirited, while the Slovenian programme looks for a trusting, balanced character with a lively temperament and a marked willingness to work.

How a Thoroughbred behaves under saddle depends heavily on its history. A young horse straight out of a racing yard is used to the pace of race training and a routine quite different from a leisure horse's, whereas an older, well-retrained Thoroughbred can be calm and dependable. With this breed the individual horse always matters more than the breed label.

Flat racing and jump racing

Racing is what the breed exists for. Britannica says the Thoroughbred was developed in England for racing and jumping, and lists flat and jump racing among its uses. The Slovenian breeding programme states outright that the breed is bred solely for flat racing, yet its breeding goal still mentions other equestrian sports.

Away from the track, Britannica notes that the Thoroughbred excels at dressage, eventing and show jumping, while horses with one Thoroughbred parent are used, depending on their training, as hunters, polo ponies, stock horses or riding horses.

A second career after racing

A Thoroughbred can take on a new job after racing, but it needs retraining first. In Britain this is the work of Retraining of Racehorses (RoR), British horseracing's official charity for the welfare of horses retired from racing. It was launched by what was then the British Horseracing Board in April 2000 and gained charitable status that autumn. RoR sets industry standards for retraining former racehorses, educates owners and runs competitions for former racehorses across a range of disciplines; its aim is a balance between the number of horses leaving racing and the number of suitable new homes.

For a new owner this means an ex-racehorse is not a finished leisure horse. It knows how to gallop in company on a track, but not necessarily how to stand quietly when tied up, hack out alone or work in an arena. Gradual retraining with a trainer who knows racehorses is part of the purchase, not an optional extra.

An improver of other breeds

The Thoroughbred has shaped almost every modern breed of hot-blooded horse, and according to the Slovenian breeding programme it is still used fairly often in their breeding to improve particular traits. Britannica explicitly mentions Thoroughbred influence in the Hanoverian and the Trakehner. The breeding programme for the Slovenian warmblood also accepts Thoroughbred stallions that meet conditions on racing performance or a performance test, as well as Thoroughbred mares.

Thoroughbred or Slovenian warmblood?

The Thoroughbred is a closed racing breed, while the Slovenian warmblood is an open sport horse breed that uses the Thoroughbred as one of its building blocks. The warmblood stud book accepts horses of every breed whose society belongs to the World Breeding Federation for Sport Horses (WBFSH), plus Arabian, Anglo-Arab and Thoroughbred stallions. Warmblood breeding allows natural cover, artificial insemination and embryo transfer; Thoroughbred breeding allows natural cover only. Slovenian warmblood stallions measure 160–170 cm and mares 155–170 cm under their programme, a little more than Thoroughbreds. Under its breeding goal the Slovenian warmblood is suited above all to show jumping, but also to dressage and driving, whereas the Thoroughbred is bred for speed on the racecourse.

Who it suits, and who it suits less

The Thoroughbred suits an experienced rider best, or a rider supported by a trainer who has worked with Thoroughbreds. A novice can ride an older, well-retrained Thoroughbred under professional supervision, but a young horse fresh from racing is generally not a beginner's horse. Children should work with a Thoroughbred only alongside an experienced adult, because it is a large, fast and sensitive horse that can spook without warning.

It makes a good partner for a sport rider looking for a quick horse with jumping talent for eventing or show jumping, and for a patient owner who wants to retrain an ex-racehorse step by step. It suits less well someone who expects a placid horse for occasional riding without regular work.

Forage, turnout, hooves and teeth

A Thoroughbred needs the same basic care as any horse: the company of other horses, daily turnout and a diet built on hay or grazing. The UK Code of Practice for the welfare of horses (DEFRA) stresses that horses are herd animals and that isolating a horse from other horses can have a negative psychological impact; another species is only a second-best companion. The same code notes that in a natural state horses spend 16–20 hours a day grazing and foraging, so outside work they should have almost constant access to grass, hay or haylage, and always fresh, clean water.

Under the DEFRA code, concentrates should be no more than the type and amount of work, or any needed weight gain, require. The code also says any change in diet should be made gradually, which applies to a Thoroughbred moving from a racing diet to one with more forage and less hard feed. Hooves should be trimmed or re-shod as the farrier advises, usually every 4–8 weeks, and teeth checked by a vet or qualified equine dental technician at least once a year. A vaccination and parasite-control plan is best drawn up with your vet; the DEFRA code notes that the right vaccinations depend on the horse's age and use.

Gastric ulcers and bleeding from the lungs

Two health problems are well documented in racehorses in training: gastric ulcers and exercise-induced bleeding from the lungs. The Merck Veterinary Manual reports that about 30% of adult horses have stomach ulcers, rising to as many as 90% of racehorses; ulcers are least common in horses turned out on pasture and most common in Thoroughbred racehorses at the track. They can develop in as little as five days. The manual lists high-concentrate diets, intermittent feeding, stall confinement and stress from travel or social interaction among the risk factors.

Exercise-induced pulmonary haemorrhage (EIPH), according to the same manual, is common in racehorses and also occurs in other horses that work at maximum effort for short periods. Blood from the nostrils is seen in only about 5% of affected horses, while examinations of racehorses have found blood in the airways of most of them. Both problems are linked mainly to intensive training rather than to the breed as such, and signs in an individual horse are for a vet to assess.

Lifespan and making the decision

We found no reliable source for a lifespan specific to the Thoroughbred. The Merck Veterinary Manual gives an average of 25–30 years for horses in general, depending on health, care and size; since a racing career lasts only a few years, a Thoroughbred can have many years of other work ahead of it afterwards.

Before buying, check the horse's passport and its entry in a recognised stud book, and with an ex-racehorse also ask how far its retraining has gone and who will help you continue it. Consider whether you can provide daily turnout with other horses, enough forage, regular farrier and dental visits and consistent work. It is worth keeping a running record of vaccinations, farrier visits and dental checks so the horse's health history is always to hand.

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