Equine gastric ulcer syndrome in the horse: The effect of diet and food withholding, and a comparison between the efficacy of esomeprazole and omeprazole on gastric fluid PH

Abstract

In horses, dietary and pharmacological manipulation of gastric fluid pH is commonly recommended for the prevention and treatment of equine squamous gastric ulcer syndrome (ESGUS). The research in this thesis consisted of two principal studies to further investigate these factors and test a newly developed alkalising medication for horses. The first study was used to develop a model for testing the efficacy of alkalising medications used for the treatment of gastric ulcers in horses. It set out to compare the gastric fluid pH of horses fed a concentrate based diet with those fed a lucerne hay diet, and assessed the effects of food withholding on the gastric fluid pH measurements of horses on these two diets. The second study compared the effects of two different alkalising medications on gastric pH in horses. The aim of this research was to compare the efficacy of a newly developed, compounded, esomeprazole paste to a commercially available omeprazole paste at maintaining a gastric fluid pH of > 4 in horses. The results of the first study showed that using the food withholding model there was no difference in the mean gastric fluid pH between horses fed a concentrate based diet when compared to horses fed lucerne hay. Furthermore, there were large variations in gastric fluid pH in horses fed either diet. The results of the second study show that using this model esomeprazole paste was equally as effective as a commercially available omeprazole paste at increasing gastric pH in horses. Esomeprazole oral paste therefore has the potential to be a useful option for the prevention of gastric ulcers in horses. The developed model allowed for a successful pilot trial investing esomeprazole oral paste as a useful treatment for ESGUS. However, future studies on oral esomeprazole paste should be directed at performing clinical trials in horses to evaluate the efficacy of esomeprazole in the treatment and prevention of ESGUS in horses.