Impact of dietary components on phenotypic measurements for Equine Metabolic Syndrome

Abstract

Previous studies in healthy horses have demonstrated that dietary adaptation has an impact on many of the phenotypic variables measured and used as diagnostic criteria for horses with presumptive equine metabolic syndrome (EMS). However, the relationship between dietary intake and measured responses in EMS horses is less understood. Our objectives were to evaluate the relationships between dietary components and phenotypic variables used as EMS criteria and todetermine if the relationship differs based on obesity or previous laminitis status. Biochemical and dietary data were collected from 634 horses from 167 farms located throughout the United States and Canada. Biochemical variables were measured in the fasted state (insulin, glucose, triglycerides, NEFA and leptin concentrations) and after an oral sugar test (glucose and insulin concentrations. For each individual, total daily dietary consumption was calculated by weighing the daily rations of hay and concentrate and estimating pasture consumption based on hours of pasture access per day. Concentrate, hay and pasture samples were analyzed (Equi-Analytical, Ithaca, NY). Total daily digestible energy, crude protein, neutral detergent fiber, water soluble carbohydrates, and starch were calculated as a percent body weight in dry matter intake. Correlations with dietary components adjusted for obesity, previous laminitis status, age, breed, sex, and exercise were determined using a mixed effects model with farm as a random effect. Interaction terms were included in the model to detect differences in the correlations between dietary components and EMS phenotypic