Bit-Related Lesions in Event Horses After a Cross-Country Test

Kati Tuomola; Nina Mäki-Kihniä; Anna Valros; Anna Mykkänen; Minna Kujala-Wirth

doi:10.3389/fvets.2021.651160

Bit-Related Lesions in Event Horses After a Cross-Country Test

Front Vet Sci. 2021 Mar 31:8:651160. doi: 10.3389/fvets.2021.651160. eCollection 2021.

Authors

Kati Tuomola¹, Nina Mäki-Kihniä², Anna Valros¹, Anna Mykkänen³, Minna Kujala-Wirth⁴

Affiliations

¹ Department of Production Animal Medicine, Research Centre for Animal Welfare, University of Helsinki, Helsinki, Finland.
² Independent Researcher, Pori, Finland.
³ Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
⁴ Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.

Abstract

Bit-related oral lesions are common and may impair horse welfare. The aim of this study was to investigate the prevalence of oral lesions and their risk factors in a sample of Finnish event horses. The rostral part of the oral cavity (the bit area) of 208 event horses (127 warmbloods, 52 coldbloods, and 29 ponies) was examined in a voluntary inspection after the last competition phase, i.e., the cross-country test. Acute lesions were observed in 52% (109/208) of the horses. The lesion status was graded as no acute lesions for 48% (99/208), mild for 22% (45/208), moderate for 26% (55/208) and severe for 4% (9/208) of the horses. The inner lip commissure was the most common lesion location observed in 39% (81/208) of the horses. A multivariable logistic regression model with data of 174 horses was applied to risk factor analysis. Horses wearing thin (10-13 mm) (OR 3.5, CI 1.4-8.7) or thick (18-22 mm) (OR 3.4, CI 1.4-8.0) bits had a higher risk of moderate/severe lesion status than horses wearing middle-sized (14-17 mm) bits (P = 0.003). Breed was associated with moderate/severe lesion status (P = 0.02). The risk was higher for warmbloods (reference group) and coldbloods (OR 2.0, CI 0.88-4.7) compared with ponies (OR 0.2, CI 0.04-0.87). Mares were at higher risk of moderate/severe lesion status (OR 2.2, CI 1.1-4.5) than geldings (reference group) (P = 0.03). Bar lesions were more common in horses with unjointed bits (40%, 8/20) than with basic double-jointed (10%, 5/52), formed double-jointed (8%, 6/78) or single-jointed bits (5%, 2/40) (Fisher's exact test, P = 0.002). The results of this study suggest that thin and thick bits and mare sex should be considered risk factors for mouth lesions. In addition, in this sample ponies had smaller risk for lesions than other horse breeds. We encourage adopting bit area monitoring as a new routine by horse handlers and as a welfare measure by competition organizers for randomly drawn horses.

Keywords: BIT; Ulcer; animal welfare; eventing; horse.