CHEYENNE, Wyo. (AP) — At least six animals died during the Cheyenne Frontier Days rodeo. the ap reports that five steers or calves died or were euthanized out of the 4,500 animals that participated in the 10-day event. A 15-year-old steer wrestling horse also died during competition but an autopsy found a pre-existing heart condition, not an injury, was to blame. The fate of four other animals released to their owners after suffering serious injuries isn't known. Animal rights activists returned to the rodeo this year and posted online videos of events they find objectionable, including the roping of larger steers. Activists believe they're more likely to be injured when they're caught. Rodeo organizers dispute that and say that anyone who violates the rules will be penalized.