Abstract
BACKGROUND: Equine inflammatory bowel disease (IBD) is challenging to diagnose and treat. Although the number of horses examined due to suspicion of IBD is increasing, the different treatments in clinical patients and their responses are not well documented. We sought to characterize the demography, signs, clinical and rectal biopsy findings, and treatment response in Finnish horses suspected to have IBD. Horses undergoing clinical examination due to suspected IBD in 2022 and with a good-quality rectal biopsy were selected for the study. General information, signs, clinical and histological findings, and treatment response were collected retrospectively from owners and participating clinics. The effect of variables on symptoms, treatment response, and biopsy results was assessed using statistical methods (significance level P < 0.05). RESULTS: A total of 152 horses was included. The most common signs were poor performance (68%), nonspecific pain (43%), and irritation/aggression (41%). Intestinal signs were observed in 63% of horses. Sixty-six percent of horses had ultrasonographic changes in the small intestine, and 37% had gastric ulcers. Orthopaedic examination was mentioned in 12% of horses. In rectal biopsy, horses had eosinophilic (35%), lymphoplasmacytic (18%), or neutrophilic (6%) inflammation; 40% had no inflammation. Inflammation was observed mostly in horses aged 5-8 years (P = 0.015). Changes in rectal biopsy were associated with certain behaviour changes (P = 0.002). Sixty-eight percent of horses were treated with medication and dietary change. Glucocorticoids were first-line treatment in 73% of medicated horses. Medication was changed during treatment in 35 horses. Treatment response was considered good in 49% of horses. Access to pasture was associated with a reduction in signs (P = 0.001). Signs, clinical and biopsy findings, and treatment type were not associated with treatment response. Medication change was associated with poorer treatment response. CONCLUSIONS: Most horses had at least a partial positive treatment response. Investment in pasture-like management, forage, and exercise regimen may be helpful during out-of-pasture season. Performance issues and nonspecific behaviour changes should be included as possible IBD-related signs, but a more structured clinical diagnostic workup is needed for a reliable assessment of treatment response and to increase the diagnostic value of rectal biopsy.