Undercover video of alleged horse abuse by a widely known trainer prompted Pepsi to pull its sponsorship of the industry's premiere show, the Tennessee Walking Horse National Celebration in Shelbyville, Tenn.
An attorney for the trainer, Jackie McConnell, said his client expects to plead guilty in a related case next week.
McConnell, of Collierville, Tenn., and three employees are charged in a 52-count indictment in U.S. District Court in Chattanooga. He and two of the three are scheduled for a hearing Tuesday.
"My client is scheduled to enter a plea to count one of the indictment next week," McConnell's lawyer, Tom Greenholtz, said Thursday. Count one was conspiracy to violate the Horse Protection Act.
The video aired Wednesday on the ABC News program "Nightline." The report said Pepsi dropped its sponsorship after "Nightline" contacted the soft drink company, a spokesman for the Humane Society of the United States said Thursday.
Humane Society spokesman Keith Dane said in a conference call that the video and media reports created a public relations problem for the walking horse industry.
"It's important that people know what's going on in the Tennessee walking horse industry," Dane said. "For anyone who loves animals to watch this will draw a visceral reaction."
Much of the "Nightline" reporting followed reports in the Chattanooga Times Free Press in recent months. Both focused on a practice known as "horse soring," in which trainers use chemical or mechanical items such as kerosene and metal bolts to exaggerate the natural walking horse gait.
The exaggerated gait, known as the "Big Lick," is prized in competitions.
At Thursday's news conference, the Humane Society released recordings showing what it said were undercover recordings of McConnell soring a horse.
Dane discussed the video and the undercover work of one of the group's agents in a seven-week operation last year to provide federal prosecutors with evidence against McConnell, 60.
During the alleged incident, McConnell was on a five-year suspension from competitions because of similar violations.
In the news conference, Dane answered questions from reporters and complimented the work of local U.S. Attorney Bill Killian and his staff for pursuing charges.
Three other defendants who worked for McConnell pleaded guilty and were sentenced earlier this year on horse soring-related charges. Those were the first criminal convictions under the 1970 Horse Protection Act in at least 20 years, according to prosecutors.