Hypertension and insulin resistance in a mixed-breed population of ponies predisposed to laminitis.
Authors: Bailey, Habershon-Butcher, Ransom, Elliott, Menzies-Gow
Journal: American journal of veterinary research
Summary
# Editorial Summary Bailey and colleagues investigated whether laminitis-prone ponies exhibit distinctive metabolic characteristics compared to unaffected peers, particularly across seasonal pasture changes. Their study compared 40 laminitis-susceptible ponies with 40 controls during winter and summer grazing, measuring body condition, blood pressure via oscillometry, and serum markers including insulin, glucose, triglycerides, uric acid, and ACTH. Remarkably, no metabolic differences emerged during winter, but summer pasture exposure triggered a marked shift in laminitis-prone ponies: they developed significantly elevated serum insulin and triglyceride concentrations, increased uric acid, demonstrated relative insulin resistance, and exhibited substantially higher blood pressure (median 89.6 mm Hg versus 76.8 mm Hg in controls). These findings establish that laminitis predisposition involves a seasonally triggered metabolic syndrome encompassing both insulin dysregulation and hypertension—a "prelaminitic phenotype" that remains silent during winter grazing but emerges acutely on summer pasture. For practitioners, this implies that apparently healthy laminitis-prone ponies in winter may harbour underlying susceptibility that summer conditions unmask; proactive management strategies (restricted grazing, low-sugar forage selection, monitoring during transition periods) warrant particular emphasis for at-risk individuals during spring and summer months.
Read the full abstract on PubMed
Practical Takeaways
- •Laminitis risk in susceptible ponies is seasonal and linked to summer pasture; metabolic screening during winter may not identify at-risk individuals
- •Monitor blood pressure and insulin status during summer months in laminitis-prone ponies as markers of metabolic syndrome and laminitis risk
- •Pasture management and dietary restriction during summer grazing periods may be critical preventive strategies for laminitis-prone ponies
Key Findings
- •Laminitis-prone ponies showed no metabolic differences from controls in winter but demonstrated significantly elevated serum insulin, triglycerides, and uric acid in summer pasture conditions
- •Laminitis-prone ponies were insulin resistant compared to controls during summer (measured by derived proxies from basal insulin and glucose)
- •Mean systolic blood pressure was significantly higher in laminitis-prone ponies during summer (89.6 mm Hg) versus controls (76.8 mm Hg)
- •Summer pasture exposure triggers a prelaminitic metabolic phenotype including hypertension and insulin resistance that is not apparent during winter grazing