During the 2012 Tevis Cup 100-mile endurance ride, Langdon Fielding, DVM, Dipl. ACVECC, of Loomis Basin Equine Medical Center, in California, and head Tevis veterinarian Greg Fellers, DVM, oversaw a research project aimed at improving veterinarians’ ability to quickly and accurately identify horses in danger of metabolic failure. And the team is back again this year to further that research.

A preliminary analysis of data taken last year from approximately 176 horses at the 36-mile checkpoint, Robinson Flat, showed that lower chloride values in the blood were associated with a horse’s failure to complete the event.

“This research project looked to answer two questions,” Fellers said. “Is it possible to sample on-site during a competition and run results within an hour hold? Second, is there something in the blood work that can help officials identify a horse that might have trouble coping with the exertion of the ride and be unable to complete?”

The research team tested blood samples for packed cell volume, plasma protein, acid/base balance, and electrolytes. They also looked at recorded physical exam parameters such as heart rate and capillary refill recorded at the same 36-mile check point; however, none of those were associated with future problems.

“The lower chloride levels are associated with a loss of chloride from sweating and an indirect measure of the decrease in blood volume,” explained Fellers.

The researchers’ ultimate goal is to create a metabolic score based on field blood work and to improve event completion rates and prevent injury to the horses. For now, Feller