The chuckwagon driver whose horse died at the Calgary Stampede on Monday following a race in the GMC Rangeland Derby says he's devastated by the loss.

"His name was Dylan and he was the family favourite," said Troy Dorchester. "He meant a lot to us, it was a real hard night in the barn, and again this morning, it's just kind of dealing with the loss of a real good friend."

During the second heat of the nightly chuckwagon races, the horse required veterinary care for "a serious internal medical condition," the Stampede said in a release.

The horse died as a result of that condition.

I think they love the sport as much as the drivers do. - Troy Dorchester, chuckwagon driver

"It was really at the start of the race so between the first and second corner Troy realized something wasn't right and did pull up his team and that horse was down and did require veterinary attention," Kristina Barnes with the Stampede said.

Dorchester, a third generation chuckwagon driver who won the Rangeland Derby in 2012, said the animal was part of the family and loved to race.

"I think they love the sport as much as the drivers do," he said.

Debate over animal welfare

The Vancouver Humane Society called on the Canadian Veterinary Medical Association to speak out against the Stampede rodeo events after the animal's death in a release.

It was the first animal death at the Stampede this year.

"Why is the CVMA silent on the abuse of these animals, which are subjected to fear, pain and stress for the sake of entertainment," said VHS spokesperson Peter Fricker.

In response, the association said that veterinarians are on site for the entire event to ensure animals are well taken care of, and that Calgary Humane Society employees have unrestricted access to the grounds.

"The CVMA does accept the use of animals in entertainment and recreation when the animal's physical social and behavioural needs are being met," said Dr. Mike Petrik, who is on the CVMA's animal welfare committee.

Petrik said it's a tragedy when any animal loses its life, but without knowing the details behind an animals death its hard to make any specific comments.

"I've been involved with many racehorses and they do truly understand what they're doing and very often they're very competitive. So, I mean, they are athletes and they push themselves hard," he said.

Dorchester said the horse was extremely well cared for and had frequent medical check-ups.

"They're close to your heart," Dorchester said. "When you lose one it's not a fun night. You try to rebound back and stay focused on that. It's really a tough go."

He said in 27 years this is the first horse he's lost on the track.

The 14-year-old gelding passed a veterinary exam prior to the races, and there is no indication the medical condition is specific to the chuckwagon race, Barnes said.

A post-mortem exam is underway to learn more.