A lawsuit challenging American Quarter Horse Association (AQHA) rules preventing cloned horses from being registered is headed to court this week.

Some owners have used the cloning process—which was first performed on horses in 2003—to preserve their animals’ bloodlines, particularly those of high-performance equines. In response to cloning as a way to preserve bloodlines, some breed associations ruled on whether or not cloned horses can be included in their breed registries. In 2004 the AQHA board of directors approved Rule 227(a), which prohibits cloned horses or their offspring from being included in the organization’s breed registry.

Last year Jason Abraham and two of his related companies, Abraham & Veneklasen Joint Venture and Abraham Equine Inc., filed suit against the AQHA in the U.S. District Court for the Northern District of Texas, Amarillo Division. The complaint asks the court to order the AQHA to remove Rule 227(a) on grounds that the ban on registering cloned horses and their offspring violates antitrust laws.

Atty. Nancy Stone, who represents Abraham & Veneklasen Joint Venture, was unavailable for comment. Neither Abraham nor fellow plaintiff Gregg Veneklasen, DVM, were available for comment