Dog breeds are documented in lists of antecedents called a stud book.
Dog breeds that have been documented may be accepted into one of the major registries (kennel clubs) of dog breeds, such as the FCI, KC, AKC, UKC, and other national registries such as the Japan Kennel Club. The registry places the breed into the appropriate category, called a Group. Some Groups may be further subdivided by some registries. When the breed is fully accepted, the stud book is closed and only dogs bred from dogs in the stud book will be accepted for registration. These dogs are referred to as purebred.
Dog breed clubs, especially of dogs bred for a particular kind of work, may maintain an open stud book and so may not be included in major registries. The dogs are still considered a breed. An example of this would be the Jack Russell Terrier Club of America.
Some dog breeds fit the definition of breed, especially breeds that develop naturally on islands or in isolated areas, but are few in number or have not been sufficiently documented to be registered with one of the major registries. An example of this would be the Kintamani Dog and other rare or independent breeds.
Breeds of dogs can be deliberately created in a relatively short period of time. When they breed true and have been sufficiently documented, they can be accepted by major registries. An example of this is the Cesky Terrier.
Each dog breed has a written Standard, a list of attributes that standardises the appearance of the breed, written by the breed’s founder or breed club. Dog are judged in Conformation Dog Shows on the basis of how closely the individual dog conforms to the breed standard. Breeding working dogs for show competition may cause appearance to be emphasised to the detriment of working ability.
Groups of dogs mistaken for breeds
Groups of dogs that may be mistaken for breeds include working dogs that are categorized by working style rather than appearance, although they may be of various ancestry and may not breed true. The difference between a named group of working dogs and a breed of dogs can be unclear. Examples would be the huntaway and other livestock dogs of New Zealand, the feist dogs of the southern United States, and the Patagonian sheepdogs of Argentina, which are collies mixed with other working dogs.
Landrace dogs are another grouping that often have been named but are not considered breeds. "Landrace" is a term used for early types domesticated animals, including dogs, where isolated populations of dogs are selected according to human goals; developing over time rather than through modern breeding techniques. An example of a landrace dog would be the dog described as ‘Basset’ as early as 1585. The landrace Basset was developed into the modern breeds of Dachshund and Basset Hound, as well as modern day terrier breeds.
Another group of dogs that may be mistaken for breeds are first-generation crossbreds, bred for hybrid vigor (heterosis) from two purebred dogs. An example of this would be the Labradoodle.
Mixed breed dogs may be offered a form of registration to allow them to participate in organized dog events. Often given the name All-American or AMBOR dog, the name does not signify that dogs so registered are a breed. Dogs must be spayed or neutered to be registered.
Individual dogs or small groups of dogs may use an existing breed name or be given an invented breed name and listed with little or no documentation for a fee with "registry" companies with minimal verification requirements. The dogs are then bred and marketed as a "registered" breed, sometimes as a "rare" or new breed of dogs.