A ruptured aneurysm was behind the sudden death of a horse taking part in chuckwagon training in the leadup to the Calgary Stampede, a necropsy indicates.
The aneurysm in the aorta ruptured near one of the kidneys, organisers of the Stampede reported.
The 12-year-old horse named Denny, belonging to the outfit of Reg Johnstone, collapsed and died on Tuesday after completing the team’s training run.
Denny, a thoroughbred, had been owned by Johnstone for about five years. He was acquired from another chuckwagon driver after his initial career as a racehorse in the Vancouver area.
Veterinarian Gord Atkins, from the University of Calgary, reported on the findings of the necropsy carried out by a pathologist at the university.
Atkins told journalists that Denny appeared to have a weakness in the aorta wall, possibly resulting from damage from a common equine parasite, strongylus vulgaris.
Atkins explained that, during one of its larval stages, the parasite migrates from the intestinal tract into the blood vessels, where it can cause problems. These can include clots or the potential weakening of an artery wall, which may then be susceptible to rupture.
Denny, he said, had been an unbelievably fit and healthy looking horse.
Unfortunately, he said, there was no way of identifying the potential threat and the condition would not have affected Denny’s health in any way until its rupture.
Even a total body MRI would not have been able to identify the problem, he said.
Atkins said horses at this level were subject to comprehensive parasite management programs.
“I can tell you that these horses here … they use very extensive deworming programs.
“I think wherever you have horses you have parasites like this.
“It’s all about nutrition management; it’s about deworming management
“I would consider these drivers to be managing at the highest level, but we still can’t eliminate that [threat] completely.”
Atkins said detailed microscopic examination of the tissue at the site of the aneurysm was planned to see if it could be confirmed that the weakening was a result of parasite damage.