The following information from the nutrition experts at Kentucky Equine Research is based on published research that can be found here.
Obesity has been associated with insulin resistance in horses and ponies. Performance horses such as racehorses, endurance horses and polo ponies are usually kept in relatively lean body condition, but many sport horses such as dressage horses, show hunters, and show jumpers carry greater body condition. This study was conducted to quantify whether body condition was related to resting insulin, glucose and triglycerides.
Using 181 horses and ponies in training for the winter show season in Florida, researchers recorded body weight, wither height, neck circumference, body condition score and neck crest adiposity. Blood samples were taken before each horse’s morning meal and analyzed for plasma glucose, insulin and triglycerides.
Results showed that dressage horses, show hunters and show jumpers carried significantly more body condition than polo ponies, but had similar resting insulin, glucose and triglyceride values. Pony hunters were significantly fatter than dressage horses, show hunters, show jumpers and polo ponies, and they had significantly higher resting insulin and significantly lower resting plasma glucose values. However, it appeared that overweight sport horses and ponies were less likely to be hyperinsulinemic than sedentary horses and ponies, perhaps because of their training regimen.
This report of KER’s research was published in Journal of Equine Veterinary Science.