Abstract
The impact of recommended withholding periods (RWPs) for omeprazole on the recurrence of Equine Gastric Ulcer Syndrome (EGUS) is unknown. The study was designed to compare the effect of two RWPs on EGUS recurrence post-omeprazole treatment and to determine if a nutraceutical supplement would reduce EGUS recurrence when administrated during an RWP. The study was a blinded, randomized clinical trial. Part 1: Horses were allocated to an RWP0 or RWP2 and crossed over after 4-weeks. Horses received oral omeprazole once daily, except during the RWPs at the end of the treatment periods. Part 2: Horses received omeprazole for 21 days prior to an RWP2 during which they received a nutraceutical supplement. Gastroscopy was performed on Day 0 and pre- and post- RWP. Part 1: More horses were affected by Equine Squamous Gastric Disease (ESGD) after the '2-clear-days' RWP than the 'not on race-day' RWP (p = 0.012). The prevalence of ESGD post-RWP for '2-clear-days' did not differ from day 0 (p = 0.478). Part 2: The prevalence of ESGD post-RWP was lower than on Day 0 (p = 0.046). A difference in recurrence of ESGD was present between the two common RWPs. The implications of this on the welfare of Thoroughbred racehorses warrant further discussion.