Adiposity, plasma insulin, leptin, lipids, and oxidative stress in mature light breed horses.
Authors: Pleasant R S, Suagee J K, Thatcher C D, Elvinger F, Geor R J
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: Adiposity and Metabolic Risk Factors in Light Breed Horses Pleasant and colleagues examined 300 mature light breed horses to clarify how body fat accumulation relates to insulin dysregulation, lipid metabolism, and oxidative stress—factors increasingly recognised as contributors to pasture-associated laminitis. Using fasting blood samples collected during early morning hours and blinded body condition scoring, researchers measured plasma insulin, leptin, triglycerides, non-esterified fatty acids, and red blood cell glutathione peroxidase activity alongside standardised condition assessment. Overconditioned and obese horses demonstrated significantly elevated fasting insulin and leptin concentrations compared with optimally conditioned animals (both P <0.01), whilst obese horses specifically showed elevated triglycerides (P = 0.006) and markedly reduced antioxidant enzyme activity in red blood cells (P = 0.001). These findings suggest that excess adiposity creates a metabolic environment predisposing horses to laminitis through multiple pathways—hyperinsulinaemia being the most clinically relevant—and support maintaining a body condition score below 7 as a practical target for laminitis risk mitigation. For practitioners managing at-risk horses, this work reinforces that weight management constitutes a fundamental preventative strategy rather than an ancillary concern.
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Practical Takeaways
- •Maintaining horses at BCS <7 is associated with lower plasma insulin and reduced laminitis risk, making body weight management a practical preventive strategy
- •Overweight horses show markers of oxidative stress and dyslipidemia; regular condition scoring and feed management should be routine practice
- •Elevated insulin in obese horses is a modifiable risk factor for pasture-associated laminitis, providing actionable guidance for clients managing at-risk animals
Key Findings
- •Overconditioned and obese horses had significantly higher plasma insulin levels (P < .001) compared to optimally conditioned horses
- •Obese horses demonstrated higher triglyceride levels (P = .006) and lower red blood cell glutathione peroxidase activities (P = .001) than optimally conditioned horses
- •Leptin levels were elevated in overconditioned and obese horses (P < .01) relative to optimally conditioned horses
- •Body condition score appears inversely related to markers of metabolic health and oxidative stress in light breed horses