A few dozen protesters chanted slogans like "Stampede OK, rodeo no!" and "tradition is no excuse for abuse" at the side of a busy thoroughfare, at times arguing with passersby on their way into Stampede Park.
"We would like Calgarians to know that we are not against the Stampede as a whole. If people want to party and watch Garth Brooks and go on rides, that's fine," said organizer Jeremy Thomas.
"There's other ways of celebrating our Western heritage than celebrating animal cruelty."
Michael Alvarez-Toye with the Calgary Animal Rights Coalition said he was shocked — but not surprised — when he heard three horses were killed at Thursday night's chuckwagon race, in which covered wagons pulled by horses thunder around a dirt track.
"One thing that they like to claim is that there's this great love for these animals, that they receive the best care," he said.
"If you love something, they don't expose it to such risks, such potential for death."
Adriana Shaw-Norbash, 11, said she thinks how animals are treated at the rodeo and chuckwagons is "wrong."
She said it's going to be a long time before those events go away, but there's one aspect they should do away with immediately.
"Probably one of the first things they can do is ban the calf-roping," she said.
That event features a running calf and a rider mounted on a horse. The rider must catch the calf by throwing a loop of rope from a lariat around its neck. He then dismounts from the horse, runs to the calf and restrains it by tying three legs together in as short a time as possible.
"When you see that, it's just not good — their broken necks and everything, and you can see the pain in their eyes."
On Thursday night, the left-lead horse pulling the chuckwagon driven by Chad Harden collapsed suddenly, causing a crash that injured two other horses so badly they had to be euthanized on the track. A fourth horse needed surgery and is expected to recover.
Right after the accident, Harden tearfully told reporters he was devastated.
Stampede officials say the horse that collapsed suffered from a ruptured aortic aneurysm, a pre-existing condition that couldn't have been detected before the race.
The autopsy results will be used to determine possible improvements to the Stampede's Fitness to Compete program, in which veterinarians inspect the horses before they compete and bar them from taking part if they have any injuries or other conditions.
"The Calgary Stampede, and the people who bring their animals to the Stampede, care deeply about the welfare and well-being of those animals. The Stampede works collaboratively to mitigate risks to human and animal competitors," the Stampede said in a release.