Glucose and Insulin Response of Horses Grazing Alfalfa, Perennial Cool-Season Grass, and Teff Across Seasons.
Authors: DeBoer Michelle L, Hathaway Marcia R, Kuhle Kerry J, Weber Patty Sue D, Reiter Amanda S, Sheaffer Craig C, Wells M Scott, Martinson Krishona L
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Seasonal Forage Types and Equine Metabolic Response Elevated nonstructural carbohydrates (NSC) in pasture present a significant management challenge for horses prone to metabolic dysfunction, yet forage selection strategies remain underexplored across seasons. DeBoer and colleagues conducted a controlled grazing trial in Minnesota during summer and autumn, rotating six aged horses through alfalfa, cool-season grass, and teff pastures whilst collecting blood samples at two-hourly intervals to measure glucose and insulin dynamics over an eight-hour grazing period. Teff consistently demonstrated lower NSC content alongside reduced digestible energy and crude protein compared to alfalfa and cool-season grass mixtures; critically, horses grazing teff showed significantly lower peak insulin responses in autumn, suggesting season-dependent metabolic benefits. These findings carry practical implications for managing horses with insulin dysregulation or equine metabolic syndrome, particularly during higher-risk periods when traditional pastures peak in NSC concentration. Whilst the small sample size and limited geographic/climatic context warrant caution in broad application, the teff data warrants further investigation as a potential strategic forage option for metabolically compromised horses during autumn months when conventional pasture quality becomes problematic.
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Practical Takeaways
- •For horses prone to laminitis or insulin dysregulation, teff may be a safer pasture option than alfalfa or cool-season grasses, particularly in fall months
- •Monitor individual horses' responses to different forage types, as NSC content and metabolic effects vary seasonally and by species
- •Consider rotating or substituting pastures with teff for insulin-sensitive or metabolically challenged horses as a practical management strategy
Key Findings
- •Teff had significantly lower equine digestible energy, crude protein, and NSC compared to alfalfa and cool-season grasses
- •Differences in peak insulin concentration were observed between horses grazing cool-season grass and teff during fall grazing (P ≤ 0.05)
- •Grazing teff resulted in lower glucose and insulin responses compared to other forage types in some horses
- •Forage type and season both influence blood glucose and insulin responses in grazing horses