Using the Horse Grimace Scale (HGS) to Assess Pain Associated with Acute Laminitis in Horses (Equus caballus).
Authors: Dalla Costa Emanuela, Stucke Diana, Dai Francesca, Minero Michela, Leach Matthew C, Lebelt Dirk
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Horse Grimace Scale for Assessing Acute Laminitis Pain Acute laminitis causes severe pain that persists both during the initial inflammatory phase and chronically, yet the standard Obel grading system requires horses to move—potentially exacerbating their condition—to assess severity accurately. Researchers from multiple institutions evaluated whether the Horse Grimace Scale (HGS), a facial-expression coding system already validated for other pain states, could provide a reliable alternative by assessing pain at rest in ten acutely laminitic horses, scoring them at admission and seven days post-treatment using both still images and video footage. Horses with high HGS scores demonstrated significantly higher Obel grades and were classified as experiencing greater pain by veterinary clinicians, with good inter-observer reliability for both image and video assessment methods showing no statistically significant difference between the two formats. This offers farriers, vets and other equine professionals a non-invasive way to monitor pain progression without forcing painful movement, potentially allowing more frequent and sensitive clinical monitoring during treatment. Although further validation studies are essential before implementing HGS routinely in practice, the technique's feasibility for brief clinical observation—requiring only 30 seconds of visual assessment—makes it a promising adjunct to existing pain evaluation protocols in acute laminitis cases.
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Practical Takeaways
- •HGS offers a pain assessment tool for acute laminitis that does not require the horse to move, reducing iatrogenic pain compared to traditional Obel scoring during examination
- •You can assess HGS from brief visual observation in the stable without video recording, making it practical for clinical use alongside or potentially as an alternative to Obel grading
- •Good inter-observer reliability means different staff members can apply HGS consistently, though further validation studies are still needed before fully replacing movement-based assessments
Key Findings
- •Horses with high Horse Grimace Scale (HGS) scores also exhibited higher Obel scores, indicating HGS correlates with clinical severity assessment
- •Inter-observer reliability of HGS total score was good for both still images and video evaluation in acute laminitis cases
- •No significant difference in HGS total scores between still images and videos, suggesting HGS can be applied in clinical practice through short observation periods
- •HGS allows pain assessment at rest without requiring movement (walk/trot), avoiding additional pain induction compared to Obel grading