A crash during a chuckwagon race at the Calgary Stampede that left three horses dead was caused when one of the horses suffered a heart aneurysm, an autopsy shows.
In a release, Stampede officials said the horse suffered from a weak blood vessel in its heart that burst, causing blood to fill the animal’s abdomen.
When the horse collapsed it bought down two other horses on his team and sent the chuckwagon driver and an outrider flying through the air.
The horse died by the time veterinarians arrived to the scene. The two other horses had to be euthanized on the track due to their extensive injuries, and a fourth horse will require surgery for its injuries but is expected to survive.
Neither man was hurt.
Veterinarian Greg Evans said the heart condition is undetectable in animals and the vessel could have ruptured at any time during exercise.
Video of the race showed officials rushing onto the course and quickly blocking off the crash scene with dark tarp-like material.
"These horses are cared for; they are loved by the drivers themselves and there's no question it's a tragedy for these families,” said Stampede spokesman Doug Fraser.
The evening’s remaining five heats went ahead as scheduled.
Fraser said Stampede organizers had hoped to wrap up the Stampede’s centennial festivities without any animal deaths. He said the driver of the chuck involved is devastated as is the chief veterinarian.
"We've had absolutely phenomenal success this year, up until tonight."
In chuckwagon races at the Stampede, four wagons pulled by four horses thunder around a dirt track, while two cowboys, known as outriders, gallop on horseback near their teams.
This isn’t the first time an incident at the chuckwagon races at the Calgary Stampede has led to animal deaths. In 2010, two horses died of heart attacks during competitions. In all that year, six horses died in various events.
The chuckwagon races along with calf roping are two events that have both come under the most fire from animal rights activists, who say the events too often put the animals at risk.
Since 1986, about 50 horses have died during chuckwagon races at the Stampede.
Immediately after the crash, the Vancouver Humane Society demanded a full suspension of the chuckwagon heats and called for an independent safety review of the event.
“Clearly, the Stampede’s much publicized safety improvements have failed to make the race any safer,” Vancouver Humane Society spokesperson Peter Fricker said in a statement. “Horses continue to die needlessly. This has to stop.”
The Stampede introduced changes last year aimed at making chuckwagon races safer for both horses and drivers.
All horses are now inspected by veterinarians when the animals arrive at the Stampede and before and after every race. There is also a mandatory rest day after every four days of racing.
The number of outriders that accompany each chuckwagon was reduced to two from four in an effort to reduce congestion.
Thursday marked the seventh day of the chuckwagon races. The finals run on Sunday.
With reports from The Canadian Press
