of most reputable breed clubs. They may provide volume discounts for registrations by commercial dog breeders such as puppy mills. An unscrupulous registry for dogs or horses is often spotted by a policy to not require any proof of pedigree at all. In the dog world, such registries may not sponsor competitions and thus cannot award championship points to identify the best individuals registered within a particular breed or species. In the less-organized world of horse shows, where many different sanctioning organizations exist, some groups sponsor their own competitions, though wins at such events seldom carry much prestige in mainstream circles. Some registers have the word "registry" in their title used in the sense of "list"; these entities are not registers in the usual sense in that they do not maintain breeding records. In the dog world, listed animals are required to be de-sexed. The American Mixed Breed Obedience Registry is an example. Some equestrian organizations create a recording system for tracking the competition records of horses, but, though horses of any sex may be recorded, they also do not maintain breeding or progeny records. The United States Equestrian Federation is one organization that uses such a system. Types of stud books Closed A closed stud book is a stud book or breed registry that does not accept any outside blood. The registered animals and all subsequent offspring trace back to the foundation stock. This ensures that the animal is a purebred member of the breed. In horses, an example of a closed stud book is that of the Thoroughbred, with a stud book tracing to 1791. The American Kennel Club is an example of a kennel club with primarily closed books for dogs; it allows new breeds to develop under its Foundation Stock Service (FSS), but such dogs are not eligible for competition in AKC conformation shows, although they do compete at those shows in the FSS category. For the breed to move to the Miscellaneous class and then to fully recognized status, the breed's stud book must be closed. A closed stud book allows the breed to stay very pure to its type, but limits its ability to be improved. For instance, in performance disciplines, an animal that is successful in competitions is generally worth more than one that is pure. It also limits the gene pool, which may make certain undesirable characteristics become accentuated in the breed,