It's been called the "half mile of hell," and for some horses, it is all that.
The famed chuckwagon races at the Calgary Stampede have been a major target of animal-welfare activists.
Horses sometimes die in the chaotic races, some put down after breaking their legs in crashes and others simply expiring from the stress.
But on the eve of the centennial edition of the "Greatest Show on Earth," which runs July 6-15, the Stampede's supporters are showcasing new research they claim can reduce the chances of death in its signature event.
The Globe and Mail reports a new study is underway aimed at detecting heart problems in horses before they run.
Dozens have already been wired up with electrodes that provide wireless telemetry to electrocardiogram monitoring gear.
"Nowadays, in veterinary medicine there's very much a push on for evidence-based decision making," chief Stampede veterinarian Greg Evans, a partner with Moore Equine Veterinary Centre in Calgary, told the Globe. "We want hard scientific data."
Since 1986, about 50 horses have died in chuckwagon racing, the Globe said. Six horses died at the Stampede in 2010, four of them in chuckwagon races, while there were 40 other injuries among the 7,500 animals used at the Stampede. Two horses died in last year's races.
[Related: PETA to royal couple: Cancel Stampede visit]
The incidents have spurred greater investment in animal-welfare research. But Peter Fricker of the Vancouver Humane Society, which has led the fight against animal cruelty at rodeos, said the combination of speed, the closeness of the careening wagons and the course's tight turns make chuckwagon racing especially dangerous.
"If they can prove they can overcome all of those issues, then we wouldn't have the same concern," he told the Globe, but also added, "we just think it's wrong to subject animals to abuse for entertainment."
The Vancouver group also lobbied Calgary Mayor Naheed Nenshi to support its effort to drop calf-roping events at Stampede, The Canadian Press reported.
Nenshi, who sits on the Stampede's board of directors, politely declined, saying Stampede organizers have the final say.
"Your inquiries and campaign should be directed toward that organization," Nenshi said in a letter to the humane society. "However, I can say that the Calgary Stampede takes animal care very seriously and has been recognized across North America for its commitment to ensuring the health and safety of all the animals that participate in Stampede-related events."
Pressure from the humane society prompted the important Cloverdale Rodeo, which takes place in the Vancouver suburb of Surrey, to drop calf roping, steer wrestling and team roping in 2007 on orders of Mayor Diane Watts.
Animal-welfare activists have also taken aim at Stampede sponsors, according to CTV News.