Horses with previous episodes of laminitis have altered insulin responses to seasonal oral sugar testing and grazing compared to horses with no known history of laminitis.
Authors: Kaufman K L, Suagee-Bedore J K, Johnson S E, Ely K M, Ghajar S J, McIntosh B M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Horses with a previous laminitis episode demonstrate persistently elevated insulin responses both at pasture and during oral sugar testing, a finding that may reflect underlying metabolic dysfunction rather than simply greater body weight or condition. Researchers monitored six previously laminitic mares alongside six controls over an extended grazing period, collecting monthly blood samples for glucose and insulin analysis whilst also performing modified oral sugar tests (using 0.30 mL/kg bodyweight of corn syrup) and recording body condition, cresty neck scores, and pasture nonstructural carbohydrate composition. The previously laminitic group exhibited significantly higher fasted insulin concentrations at baseline (T0), higher insulin and glucose responses 75 minutes post-sugar challenge (T75), and greater regional adiposity (cresty neck scores), despite seasonal variation affecting all horses. These findings indicate that laminitis history appears linked to a dysregulated metabolic phenotype characterised by insulin dysregulation, suggesting that grazing management and dietary intervention strategies for at-risk individuals should account for exaggerated postprandial insulin spikes rather than relying solely on pasture NSC reduction. For practitioners managing previously affected horses, this research reinforces the importance of basal and dynamic insulin assessment through oral sugar testing to inform individual risk stratification and forage management protocols.
Read the full abstract on PubMed
Practical Takeaways
- •Horses with a history of laminitis show exaggerated insulin responses to pasture grazing and oral sugar challenges; monitor these horses more closely during high-NSC seasons and consider restricted grazing or NSC-limiting diets
- •Regional adiposity (cresty neck score) correlates with insulin dysregulation in laminitis-prone horses; weight and condition management should be prioritized year-round to reduce metabolic risk
- •Monthly or seasonal insulin testing via oral sugar test may help identify at-risk horses earlier and guide nutritional interventions before clinical laminitis recurs
Key Findings
- •Horses with previous laminitis (PRELAM) had significantly greater cresty neck scores (P < 0.001), body weight (P < 0.05), and body condition scores compared to horses with no laminitis history (NOLAM)
- •Fasted insulin concentrations at baseline (T0) were greater in PRELAM horses and affected by month and group (P < 0.001)
- •PRELAM horses exhibited higher glucose and insulin concentrations 75 minutes after oral sugar test (P = 0.003 and P = 0.002 respectively)
- •Non-fasted insulin on pasture was influenced by group by month interaction (P = 0.004), indicating altered seasonal insulin response patterns in laminitis-prone horses