Assessment of Pain in Horses With EGUS

Abstract

Pain is a subjective experience, making pain assessment difficult. In animals, this becomes even more complicated, especially when assessing pain in conditions that are only presumed to be painful such as equine gastric ulcer syndrome. Characterised by lesions on the mucosa of the equine stomach, this disease has a prevalence of 60-100% . It is not known whether gastric ulcers are painful for horses. The aim of this study was to use subjective (horse grimace scale) and objective (interleukin-1ꞵ) measures to determine if horses with equine gastric ulcer syndrome scored higher than pain-free control horses. A total of 77 horses were assessed for lameness and gastric ulcers and split into 4 groups depending on the presence and absence of each. There were no statistically significant differences between the groups when comparing horse grimace scale scores or interleukin-1ꞵ expression. There was a statistically significant association between horses with grade 4 ulceration of the squamous mucosa and heightened levels of interleukin-1ꞵ, which supported the hypothesis that horses with equine gastric ulcer syndrome would have higher levels of interleukin-1ꞵ than those with less severe ulcers. Whilst some positive results were found, further studies are required to optimize use of the interleukin- 1ꞵ assay as well as using more horses with no ulcers and more horses with severe ulcers to get more definitive results.