What are the thoroughbred breeding rules? How is thoroughbred breeding performed and why? In the United States, the rules governing registration and the procedures for registering a Thoroughbred are administered by The Jockey Club. The Jockey Club requires that all Thoroughbreds be the product of a "live cover" mating; artificial insemination is not permitted, although it is permissible to immediately "reinforce" a live cover with collected as the stallion dismounts. This practice is sometimes d