Texas horse breeder Jason Abraham and veterinarian Gregg Veneklasen sued the American Quarter Horse Assn., claiming that Lynx Melody Too should be allowed to register as an official quarter horse.

A Texas jury decided in their favor in 2013, but a three-judge panel of the U.S. 5th Circuit Court of Appeals reversed that ruling in January, saying there was “insufficient” evidence of wrongdoing by the association.

Abraham and Veneklasen are now seeking a rehearing before the full 15-judge circuit panel.

The suit is among the first to deal with the status of clones in breeding and competition, and its outcome could impact a number of fields, including thoroughbred horse racing and dog breeding.

The quarter horse association is adamant that clones and their offspring have no place in its registry.

“It’s what AQHA was founded on — tracking and preserving the pedigrees of these American quarter horses,” said Tom Persechino, executive director of marketing for the association. “When a person buys an American quarter horse, they want to know that my quarter horse has the blood of these horses running through it, not copies of it.”

But Abraham and Veneklasen say that cloning follows a long tradition of using the latest technology to improve and maintain the breed.

Cloning “is nothing more than an assisted…