Business and Professions Code § 19540

In order to encourage and develop the racing of all horses in California, regardless of breed, whenever a fair conducts a program of horse races on which there is parimutuel wagering, the fair, so far as practicable, shall provide a program of racing that includes thoroughbred racing, quarter horse racing, Arabian racing, and Appaloosa racing, if a sufficient number of horses is available to provide competition in one or more races.