Part-Arabian

A part-Arabian, partbred Arabian or, less precisely, half-Arabian, is a horse with documented amounts of Arabian horse breeding but not a purebred. Because the Arabian is deemed to be a breed of purebred horse dating back many centuries, the modern breed registries recognized by the World Arabian Horse Organization generally have tightly closed stud books which exclude a horse from registration if it is found to contain any outside blood. However, Arabian breeding has also been used for centuries to add useful traits to countless other horse breeds. In the modern era, crossbreeding has been popular to combine the best traits of two different breeds, such as color, size, or ability to specialize in a particular equestrian discipline.
Thus, in the modern era, the desire to recognize and acknowledge Arabian breeding in non-purebred horses has led to the formation of partbred sections in many purebred Arabian registries in order to record the pedigrees of crossbreds. In addition, some particularly successful or popular crossbreds have created their own registries, usually closed to most outside breeding, but which generally allow additional infusions of purebred Arabian blood. Some registries, particularly those for sport horses and various warmbloods, have an open or partially open stud book that still allows some infusions of Arabian blood as well as that of other breeds, sometimes based on a documented Arabian pedigree, sometimes on a pedigree plus a studbook selection process. There are cases where a horse may qualify for registration in more than one registry and thus may be marketed as "double-registered".
A few breeds, such as the Thoroughbred, acknowledge Arabian ancestry with named, documented horses in their stud books, but no longer accept new infusions of Arabian blood and the breed is considered a purebred in its own right. Literally hundreds of other horse breeds have some evidence of Arabian influence. In some breeds, such as the Percheron, Arabian influence is considered highly probable, but dates back hundreds of years and thus is difficult to conclusively prove as pedigree records cannot be linked to individual animals. In other breeds, such as the Andalusian horse or the American Quarter Horse, documentation of Arabian bloodlines in the breed can be found but either the records are controversial, or the infusion of Arab blood itself was controversial and for various reasons the breed registry today seeks to downplay Arabian type or influence.
Registries.
Breed registries for part-Arabians include:
Open stud books.
Horse registries with an open stud book that allow Arabian and part-Arabians as well as other breeds to be registered include:
Partially open stud books that allow Arab breeding.
Breeds with a "partially open" stud book, but that still allow new infusions of Arabian breeding, some based only on documented pedigree, some requiring a pedigree and studbook selection, include:
"Purebred" breeds with Arabian roots.
Breeds significantly influenced by acknowledged, documented Arabian foundation bloodstock recorded by their breed's stud book during their formative years, but have closed stud books that no longer accept Arabian blood directly include: