Clinical Signs as an Indication of the Presence of Gastric Ulcers in Horses: True or False?

Equine Gastric Ulcer Syndrome (EGUS) and its related diseases, Equine Squamous Gastric Disease (ESGD) and Equine Glandular Gastric Disease (EGGD), can be found in horses worldwide, with increased prevalences in racehorses and animals subjected to heavy training loads. Clinical signs of the disease are vague and nonspecific, and most horses affected by the disease are asymptomatic. In this retrospective study, our aim was to determine the percentages of pleasure and breeding horses showing signs compatible with gastric ulcers, and to correlate these signs with the presence of ESGD, EGGD, and both diseases at the same time. The effects of signalment and activity on disease development and symptoms were also investigated. In total, 1125 adult horses were enrolled in the study. Within this group, only 12% showed clinical signs related to the gastrointestinal tract (GIT, 6%), performance and behavior (PER, 1%), or weight loss (WL, 5%). ESGD was diagnosed in 63% (grade 2/4 22%, 3/4 11%, and 4/4 30%) of animals, while EGGD was diagnosed in 32%. Warmblood horses and geldings were more likely to show clinical signs compared to the other breeds and sexes. WL was associated with the presence and severity of ESGD and the presence of EGGD; GIT was associated only with the presence and severity of ESGD; and PER was associated with the severity of ESGD and the presence of EGGD. Activity was the main risk factor for the development of all diseases, modulating the effect of signalment. EGGD was the only disease with a limited effect on the manifestation of clinical signs when compared with the effect of signalment only. Despite the relatively high prevalence of the disease in horses considered at low risk, clinical signs were present in only a small percentage of the study group, with their expression possibly related to the presence and severity of gastric ulcers. Although the limited effect of EGGD on the manifestation of clinical signs needs to be confirmed, it highlights the limited knowledge we currently have on the clinical significance of lesions in the glandular mucosa, especially when only hyperemia is present.