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Home / Equine Research Bank / Animals (Basel) / Horse Grimace Scale Does Not Detect Pain in Horses with Equi...
Animals : an open access journal from MDPI2023; 13(10); doi: 10.3390/ani13101623

Horse Grimace Scale Does Not Detect Pain in Horses with Equine Gastric Ulcer Syndrome.

Abstract: Equine gastric ulcer syndrome (EGUS) is a highly prevalent and presumptively painful condition, although the amount of pain horses might experience is currently unknown. The aims of this study were to determine if the Horse Grimace Scale (HGS) could identify pain behaviours in horses with and without EGUS and if severity would be positively associated with the HGS score. Horse grimace scale scores were assessed blindly using facial photographs by seven observers and involved evaluation of 6 facial action units as 0 (not present), 1 (moderately present) and 2 (obviously present). Lameness examination, serum amyloid A (SAA) measurement and gastroscopy evaluation were performed on all horses. Horses (n = 61) were divided into two and three groups based on the presence (yes, no) and severity (none, mild, moderate-severe) of EGUS, respectively. Presence of lameness and elevated SAA (≥50 µg/mL) were used as exclusion criteria. Inter-observer reliability was analyzed by intra-class correlation coefficients (ICC). HGS scores between groups were compared using Welch's and Brown Forsythe tests (p < 0.05). Overall, HGS ICC was "excellent" (0.75). No significant differences (p = 0.566) were observed in HGS scores between horses with and without gastric lesions (mean, 95% CI; 3.36, 2.76-3.95 and 3, 1.79-4.20, respectively). HGS was not influenced by the presence or severity of EGUS in this current study. Further studies investigating the use of different pain scales in horses with EGUS are needed.
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Publication Date: 2023-05-12 PubMed ID: 37238054PubMed Central: PMC10215503DOI: 10.3390/ani13101623Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The research article investigates if the Horse Grimace Scale (HGS) can identify pain behaviors in horses suffering from equine gastric ulcer syndrome (EGUS). The findings conclude that HGS is not sensitive to detecting pain in horses with EGUS, regardless of the severity of the condition.

Context of the study

  • EGUS is a widespread condition among horses that is presumed to be painful.
  • The extent of the pain experienced by horses with this condition is not clearly known.
  • The researchers aim to use the Horse Grimace Scale (HGS) to identify signs of pain in horses suffering from EGUS, and to determine if the severity of the pain could be determined using the HGS score.

Methodology of the study

  • The HGS scores were calculated using the facial photographs of the horses, assessed by seven observers.
  • A total of 6 facial action units were evaluated and scored as 0 (not present), 1 (moderately present), and 2 (obviously present).
  • The horses were categorized into groups based on the presence and severity of EGUS.
  • Condition examinations including lameness examination, serum amyloid A (SAA) measurement, and gastroscopy evaluation were performed on all horses.
  • Inter-observer reliability was analyzed through intra-class correlation coefficients (ICC).

Findings of the study

  • The researchers found that there was an “excellent” ICC in HGS scores (0.75).
  • No significant differences were found in the HGS scores between horses with and without EGUS, meaning that the HGS was not successful in identifying horses with this condition and determining its severity.

Conclusion and further research

  • The study concludes that the Horse Grimace Scale is not effective in detecting pain associated with EGUS in horses.
  • Further research is required to investigate the usage of different pain scales in detecting and monitoring the severity of pain in horses suffering from EGUS.

Cite This Article

APA
Ferlini Agne G, May BE, Lovett A, Simon O, Steel C, Santos L, Guedes do Carmo L, Barbosa B, Werner LC, Daros RR, Somogyi AA, Sykes B, Franklin S. (2023). Horse Grimace Scale Does Not Detect Pain in Horses with Equine Gastric Ulcer Syndrome. Animals (Basel), 13(10). https://doi.org/10.3390/ani13101623

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 13
Issue: 10

Researcher Affiliations

Ferlini Agne, Gustavo
  • School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA 5371, Australia.
May, Bridget Eileen
  • School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA 5371, Australia.
Lovett, Amy
  • School of Veterinary Medicine, Massey University, Palmerston North 4474, New Zealand.
Simon, Olivier
  • School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA 5371, Australia.
Steel, Catherine
  • Department of Veterinary Clinical Services, Hong Kong Jockey Club, Sha Tin Racecourse, New Territories, Hong Kong.
Santos, Luiz
  • School of Biodiversity, One Health and Veterinary Sciences, The University of Glasgow, Bearsden, Glasgow G12 8QQ, UK.
Guedes do Carmo, Laize
  • Graduate Program in Animal Science, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil.
Barbosa, Bianca
  • Graduate Program in Animal Science, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil.
Werner, Laís Cristine
  • Graduate Program in Animal Science, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil.
Daros, Ruan R
  • Graduate Program in Animal Science, School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil.
Somogyi, Andrew A
  • Discipline of Pharmacology, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5005, Australia.
Sykes, Benjamin
  • School of Veterinary Medicine, Massey University, Palmerston North 4474, New Zealand.
Franklin, Samantha
  • School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, Adelaide, SA 5371, Australia.

Conflict of Interest Statement

The authors declare no conflict of interest.

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Citations

This article has been cited 4 times.
  1. Frippiat T, Bonhomme M, Dyson S, Votion DM. Evaluation of Owner-Reported Clinical Signs and Fecal Occult Blood Tests as Predictors of Equine Gastric Ulcer Syndrome in Competition Dressage Horses. J Vet Intern Med 2025 Nov-Dec;39(6):e70248.
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  2. Mota-Rojas D, Whittaker AL, Coria-Avila GA, Martínez-Burnes J, Mora-Medina P, Domínguez-Oliva A, Hernández-Avalos I, Olmos-Hernández A, Verduzco-Mendoza A, Casas-Alvarado A, Grandin T. How facial expressions reveal acute pain in domestic animals with facial pain scales as a diagnostic tool. Front Vet Sci 2025;12:1546719.
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  3. Torcivia C, McDonnell SM. Behavioral Signature of Equine Gastric Discomfort? Preliminary Retrospective Clinical Observations. Animals (Basel) 2025 Jan 3;15(1).
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  4. Flores JEM, Terrazas A, Lara Sagahon AV, Aleman M. Parasympathetic tone activity, heart rate, and grimace scale in conscious horses of 3 breeds before, during, and after nociceptive mechanical stimulation. J Vet Intern Med 2024 Sep-Oct;38(5):2739-2747.
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