Equine Review

Equine gastric ulcer disease is a cause of morbidity in horses, with an incidence reported at greater than 80%. Wei Le San (WLS) is a Chinese herbal formula of nine herbs selected for putative anti-inflammatory effects. Munsterman et al (J Vet Intern Med 2019; 33:2280–2285) aimed to determine the efficacy of WLS for non-glandular gastric ulcers induced by an intermittent feeding regime, hypothesising that gastric ulceration scores would be reduced compared to controls. Ten horses underwent a 5-week trial on two occasions (treatment and placebo), to serve as their own controls. For the first week, horses were given an intermittent feeding regime, designed to induce or worsen existing ulcers. Treatment or a placebo was given from day 7. Gastroscopy was performed on days 0, 6 and 34. Gastric juice pH was measured and ulcers scored. On day 6, 8 control horses and 9 treated horses had squamous gastric ulceration, following feed deprivation. After 4 weeks of treatment 5/10 control and 4/10 treated horses had gastric ulceration. Ulcer number and severity was not different between groups (p=0.81 and 0.85 respectively). There was no difference noted in gastric pH after 4 weeks of treatment with WLS and untreated controls compared to baseline (p=0.46). The authors concluded that WLS was not effective at reducing gastric ulcer severity in horses, caused by intermittent feed deprivation.