A research team in Australia has been examining equine gastric ulcer syndrome (EGUS) from a different angle than most scientists have in the past, measuring pH levels in two areas of the stomach over time rather than testing gastric fluid from a fasted horse. In doing so, they’ve found that in some horses on certain diets, the duration of acid suppression of oral omeprazole—the current gold-standard for ulcer treatment—could be inadequate for ulcer healing. So, they’re taking the research a step further and considering alternative therapeutic approaches.

Ben Sykes, BSc, BVMS, MS, MBA, Dipl. ACVIM, Dipl. ECEIM, PhD, from The University of Queensland, presented findings from one study and preliminary results from two others at the 2016 British Equine Veterinary Association Congress, held in Birmingham, U.K., in September. In each study he and colleagues used an intragastric pH probe to monitor the acidity of the environment for 23 hours (the 24th hour was used to reset and recalibrate the probe) in the ventral (lower) region of the stomach. In the first study, which appeared in the Equine Veterinary Journal, Sykes and his team revealed that while omeprazole did a great job raising intragastric pH in horses on high-grain/low-fiber diets, it didn’t perform so well in horses on hay-only diets.

They also discovered that under some conditions there was a cumulative effect of dosing—meaning the longer the treatment regimen (measured up to five days), the higher the pH, which is a new finding in the horse. In the end, they determined that using a cookie-cutter dosing recommendation for all horses might not be appropriate, and veterinarians need to consider the diet and management of horses when making dosing recommendations.

“A hay-only diet might be a bad idea in the therapeutic stage, at least in some animals,” he said