The term “equine metabolic syndrome” describes a collection of clinical signs that contribute to the development of founder (laminitis) in horses. This syndrome is currently defined by the presence of 1) insulin resistance (IR), 2) obesity and/or regional adiposity, and 3) prior or current laminitis. IR is characterized by a loss of insulin sensitivity at the cellular level. The insulin resistant horse is carbohydrate intolerant and the degree of IR can be assessed and measured as part of the diagnosis and recovery process (Frank, 2011; Ralston, 2002). In the majority of cases, horses compensate for IR by increasing insulin secretion from the pancreas. There is a need to accurately diagnose IR in clinical practice. However, studies have shown that diagnosis of IR should not be made solely based on results from the glucose curve of the CGIT (combined glucose-insulin tolerance test). Therefore, insulin dynamics are of great importance when diagnosing a horse with IR (Bröjer et al. 2013).
Matching energy intake with energy expenditure is important for the exercising horse. Parameters such as the hormones ghrelin, adiponectin and insulin have been shown to play a major role in mediating the energy balance either through their effects on feed intake or metabolic regulation. Glucose and insulin responses are modified by multiple factors including diet, obesity, exercise level and stress. (Jansson, 2002; Gordon, 2006; Nostell, 2012; Ralston, 2002).