During the Tokyo Olympics, the German team in modern pentathlon made headlines with their treatment of the horse Saint Boy, who refused to jump out on the track.
TV pictures showing how the desperate rider Annika Schleu whips the horse to make him obey have gone viral.
After the competition came accusations that coach Kim Raisner had been seen beating Saint Boy with his fist - and the International Federation of Modern Pentathlon threw Raisner out of the Olympics.
"Fines and suspensions are not enough to protect other horses from trainers who can commit similar crimes," writes Peta.
Peta also mentions two other incidents during the Olympics.
The horse Jet Set had to be killed after suffering serious injuries to one of its hind legs during the terrain ride.
In the horse jump, the horse Kilkenny began to bleed nosebleeds, but the Irish rider Cian O'Connor still finished riding the track.
The news agency Reuters writes that the IOC could not be reached for comment.