Studbook selection

Studbook selection is a process used in certain breeds of horses to select breeding stock. It allows a breed registry to direct the evolution of the breed towards the ideal by eliminating unhealthy or undesirable animals from the population. The removal of individuals from a population is called culling, and does not suggest killing the animal in question. Typically, culls are castrated or they and their offspring are unable to be registered.

Registries which implement studbook selection differ from registries which require only two parents of the proper pedigree or registration status. For example, a horse foal with two Thoroughbred parents is almost certainly a Thoroughbred, but a foal with two Oldenburg parents may not be accepted through studbook selection to be an Oldenburg.

The pattern of studbook selection varies from nation to nation and registry to registry, but among horse registries, particularly warmblood registries, the general outline includes an inspection of foals before formal registration, evaluation of conformation and movement of broodmares, and evaluation of the conformation, movement, health, and performance ability of stallions. Decisions about which mares and stallions are suitable breeding stock are made by elected breed judges, who strive for objectivity and transparency.

Foals are usually presented at a local mare and foal show by their dam's side. If the foal's sire and dam are in the studbook, and he generally fits into the breeding goal, he receives his papers and a on the left thigh. The brand identifies his registry. Although foals are not usually scored, some registries award "Premium" status to high-quality foals, and colts may be deemed stallion prospects by the judge(s).

Foal inspections are also used to determine whether or not a stallion is producing offspring that fit the breeding goal.

The first method of evaluating breeding stock in many warmblood registries is the studbook inspection. Fillies may be evaluated at age 3 at a local mare and foal show, and colts may be evaluated at age 2 at the Körung, which translates to "breed survey", "bonitation" or "licensing".

...
Wikipedia