Study Reveals Diet's Role in Equine Insulin Resistance

A recent study from Australia indicates that diet may play a more critical role than previously thought in insulin resistance among horses. Simon Bailey, BVMS, PhD, from the University of Melbourne, noted that while obesity and insulin resistance are traditionally linked, the researchers sought to determine if dietary carbohydrates could be the main contributor to this condition, known as equine metabolic syndrome (EMS). The research involved 33 horses of different breeds, including Andalusians and ponies, which are more susceptible to EMS, and Standardbreds, which are not.

How it Works

The horses were divided into three feeding groups: one receiving a high-starch, grain-heavy diet, another receiving a calorie-equivalent diet primarily from fats, and a control group fed only hay with added protein and minerals. After 20 weeks, those on calorie-dense diets gained weight, but showed differing insulin sensitivity levels. Results indicated that horses on high-grain rations became significantly less sensitive to insulin compared to those on high-fat diets, which maintained similar insulin regulation to the control group.

The Results

The findings suggest that sustained carbohydrate absorption is a more significant factor in insulin dysregulation than obesity itself. Bailey emphasized the importance of dietary adjustments in reducing the risk of EMS-related laminitis even before substantial weight loss is achieved. Despite these insights, he cautioned that obesity remains a health concern for equines as it often correlates with high insulin levels. Recommendations for managing horses prone to EMS include avoiding high-grain feeds and spring pastures that induce high insulin levels, while using fats or low-glycemic supplements for calorie needs during work. The study also highlights genetic differences in insulin sensitivity across breeds, which can affect dietary management strategies for individual horses.