What is a Stallion?
Jesse M. Cox Last Verified
19/04/2026
A stallion is a male horse that can function at stud because castration has not taken place. Once a horse has been gelded it is not possible to be used for breeding because the reproductive equipment has been removed. Stallions have a more muscular body than mares and geldings.
Horses are herd animals but stallions can become aggressive amongst other stallions and training and management is required to make a stallion suitable for horse racing.
The term is derived from the need for an entire horse to be kept in stalls to minimise any disruption from aggressive behaviour. Uncastrated horses were not allowed to be turned out in fields or common ground.
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How is Stallion used in Sports Betting?
Once a race horse has finished a career on the track there is an option of a breeding career at stud. In flat racing there can be much more money on offer through breeding rather than racing. Flat stallions are often retired from racing at three-years-old after their career as a race horse, and the winner of the best races will have a big fee at stud.
The most important race in the world for the breeding industry is the English Derby at Epsom. The winner of this prestigious race will be a much sought after stallion and the stud value will be set accordingly. The importance of the Classics in the breeding industry is reflected by the fact that geldings are not eligible.
When assessing the potential ability of a young horse bettors can refer to the parentage which indicates the stallion and mare who produced the horse. This is particularly relevant for juvenile races in which the horses have little or no racing experience, but every race horse in the UK is related to three Arab horses.
Horses that are placed in group races are listed in black type which means their name is bolded to stand out in racing publications.