Senate Majority Leader Bill Frist of Tennessee and U.S. Sen. Saxby Chambliss (R-Georgia) have written to an undersecretary of the U.S. Department of Agriculture asking the department to study the National Horse Protection Society's proposal to clarify the definition of soring in the Horse Protection Act (HPA).

"It is our understanding that the proposal is intended to clarify the definition of soring in order to allow personnel ... to enforce the provisions of the HPA in a more consistent manner," wrote Frist and Chambliss to Bruce Knight, USDA's undersecretary for marketing and regulatory programs. "It has been asserted that the current definition of soring under the HPA is interpreted and applied differently across the country."

Frist and Chambliss ask USDA to study and comment on the National Horse Protection Society proposal and respond "in a timely manner."

The letter, dated Thursday, was posted the same day to the Walking Horse Report web site. Frist's office confirmed the text of the letter to the Times-Gazette on Friday but said it would have no other comment because of ongoing discussions.

The National Horse Protection Society, chartered in fall 2005, sought input from veterinarians from a number of equine groups including the United States Equestrian Federation (which regulates virtually all horse shows except for the Tennessee Walking Horse), Standardbred, Thoroughbreds, Grand Prix, Hunter Jumpers and the Professional Rodeo Cowboys Association. The organization's advisory committee includes a leading veterinarian, trainers and owners. Its mission statement has been endorsed by the Walking Horse Trainers' Association, the National Horse Show Commission and the Celebration.

One of the arguments in the current dispute between walking horse trainers and the USDA is the claim that enforcement of the Horse Protection Act is inconsistent. A horse may pass inspection one night and be rejected a few nights later, say industry supporters.

Frist, a transplant surgeon, is not seeking re-election to his Senate seat and is widely considered to be a candidate for president in 2008. During an interview at the 2005 Celebration, he told the Times-Gazette he remembered attending the show when he was as young as 7 years old, during the era when his father, the late HCA Corp. co-founder Dr. Thomas Frist Sr., was physician to Gov. Buford Ellington and Gov. Frank Clement.

Chambliss chairs the Senate Committee on Agriculture, Nutrition and Forestry.