According to Weatherbys, the company that administers British racing under contract to the British Horseracing Authority (BHA), the main body colours found in thoroughbred racehorses are bay, black, brown, chestnut and grey.
Bay can cover many variations of the colour brown, although typically means reddish-brown, or tan. A bay horse has a black mane and tail and a distinguishable colour line between the upper and lower sections of the legs. By contrast, a brown horse has a brown man and tail and no such colour line, although tan may be seen in the fold of the flank and/or muzzle. Purely black horses are a rarity and must be entirely black, in coat, stifle fold and muzzle, to be classified as such. Chestnut horses have a reddish or yellowish brown body colour, with a mane and tail which, while similar in shade, may be slightly lighter or darker.
Grey, too, covers a range of shades from bright white to battleship, or gunmetal, grey. Grey horses are not usually born grey, but grow lighter in colour with age, such that their body coat is a mixture of black and white hairs. Truly white horses, like truly black horses, are a rarity.
In addition to the basic body colours, certain other colours are recognised by thoroughbred and non-thoroughbred authorities. A thoroughbred described as ‘roan’, for example, is characterised by white hairs evenly intermingled with hairs of another colour, such as brown or chestnut. That said, most thoroughbreds that appear roan are in the process of going grey.
Notwithstanding the so-called Fillies’ Triple Crown, which consists of the 1,000 Guineas, Oaks and St. Leger, the term English Triple Crown is usually applied to the Two Thousand Guineas, Derby and St. Leger, all of which are open to three-year-old colts and fillies. The oldest of the three ‘Classic’ races that constitute the English Triple Crown, the St. Leger, was established in 1776, followed by the Derby in 1780 and, last but not least, the Two Thousand Guineas in 1809. However, it was not until 1853, when the aptly-named Melbourne colt, West Australian, trained by John Scott and ridden by Frank Butler, won all three races that the phrase ‘Triple Crown’ was coined. As testament to his versatility, the following season West Australian also won the Gold Cup at Ascot over two-and-a-half miles.
Grass sickness in horses, technically known as ‘equine dysautonomia’, attracted public attention when, in 2001, it caused the death of the 2000 Dubai World Cup winner, Dubai Millenium, as a five-year-old. In response, Sheikh Mohammed bin Rashid al Maktoum, ruler of the Emirate of Dubai and owner of the Godolphin stables, established the Dubai Millennium Research Foundation (DMRF) with a view to identifying the explicitly defined cause of the disease.
The cause of grass sickness remains unknown, but the disease occurs, almost invariably, in young horses, aged between two and seven years, with access to grass. The main symptom of grass sickness is gut paralysis, caused by damage to the involuntary, or ‘autonomic’, nervous system; the nature of the damage suggests the presence of a toxin and Clostridium botulinum, a bacterium that produces lethal botulinum toxins, which block nerve functions, under low-oxygen, or ‘hypoxic’, conditions, has been strongly implicated in cases of grass sickness.
Grass sickness was first identified in Scotland in the early twentieth century, where it was responsible for the deaths of hundreds of horses, predominantly draught horses, annually throughout the Twenties. There is still no dependable, explicit treatment for grass sickness and, in the worst cases, horses die or require euthanasia within 48 hours after contracting the disease. In the United Kingdom, grass sickness is estimated to kill 0.5% of horses, of all breeds, annually.
Obviously, the field size of any horse race depends, first and foremost, on the number of horses declared to run. Depending on the nature and timing of the race in question, declarations to run must be made by 10.00am one or two days before the race. However, for safety reasons, the number of runners in any race is limited according to the size and configuration of the racecourse on which the race is run; the Derby at Epsom, for example, has a safety limit of 20, while the Wokingham Stakes at Ascot has a safety limit of 30 and the Grand National has a safety limit of 40.
At the declaration to run stage, if the number of declarations exceeds the safety limit, horses are eliminated to reduce the field size. Horses are eliminated in a specified order, starting with the lowest weighted, in handicap races, or the lowest rated, in Listed or Pattern races, with a ballot if necessary, to restrict the number of runners to the maximum field size. If the number of declarations exceeds the safety limit and is 18 or more, another strategy is to divide the race into two, or possibly more, divisions.
Another consideration is the stabling capacity of the racecourse, which cannot be exceeded if every horse is to have its own stable on arrival. If the declarations for all races at a fixture, including divisions, exceeds the so-called ‘field size limit’, horses are eliminated, race-by-race, as previously described, until those that remain can adequately be accommodated at the racecourse.