Behaviour of Icelandic horses during gait competitions and the association with oral lesions

The welfare of sports horses is currently debated. Increased knowledge of behavioural signs of pain, discomfort or frustration in competition horses can help identify practices that compromise horse welfare. Increased awareness of horse behaviour may also help prevent the development of oral lesions which has previously been related to riding techniques that apply too much pressure on the horse’s mouth via the reins and bit. This study included 70 Icelandic horses competing in two breed-specific gait competitions (Five-gait F1 and Tölt T1) at the same event. All horses participating in the two competitions were included. When leaving the competition arena, each horse was examined for oral lesions by a trained inspector, and noseband and bit type were noted. Subsequently, the behaviour of the horses during the competition (mouth opening, sudden head movements, tail swishing, unexpected gait changes – jointly labelled ‘conflict behaviour’) was scored from official video recordings available online from the event. Sixteen of the 70 horses (22.9%) had oral lesions, i.e., abrasion of the skin and/or mucosa at one or both sides of the commissures of the lips. In both competitions, mouth opening was the most frequently observed conflict behaviour (e.g., in F1; median 25;75%), mouth opening: 34.0 25;54), sudden head movements: 18.0 11;25, tail swishing: 1.0 0;9, and undesired gait changes: 0 0;1, P<0.001 for all pairwise comparisons). Further, in both competitions, the frequency of conflict behaviour was higher in horses with oral lesions compared to horses without oral lesions (e.g., in F1; with lesions (n=8): 106 83;126 vs. without lesions (n=29): 50 41;64, MWU test, P<0.001). In addition, elongation of the upper lip was noted more frequently in horses with oral lesions. We conclude that conflict behaviour, and in particular oral behaviour, can be a useful indicator of oral lesions. Further studies are needed to investigate early behavioural signs of discomfort and pain in riding horses to avoid physical harm, such as the development of oral lesions. Increased awareness of horse behaviour can be a pathway towards improved sports horse welfare. • Behaviour of Icelandic horses was recorded in two gait competitions • Of the 70 participating horses, sixteen (22.7%) had oral lesions • Some exercises, e.g., pace transitions and slow tölt, led to more conflict behaviour • Horses competing with oral lesions showed more conflict behaviour • Increased awareness of behaviour of competition horses may help improve welfare