Application of the Ridden Horse Pain Ethogram to Horses Competing at the Hickstead-Rotterdam Grand Prix Challenge and the British Dressage Grand Prix National Championship 2020 and Comparison with World Cup Grand Prix Competitions.

The Ridden Horse Pain Ethogram (RHpE) comprising 24 behaviours was developed to facilitate the identification of musculoskeletal discomfort, with scores of ≥8/24 indicating the presence of pain. The median RHpE score for 147 competitors at World Cup Grand Prix events from 2018 to 2020 was three (interquartile range [IQR] 1-4; range 0-7). The aim of the current study was to apply the RHpE to 38 competitors at the Hickstead-Rotterdam Grand Prix Challenge and 26 competitors at the British Dressage Grand Prix National Championship in 2020. The median RHpE scores were four (IQR 3-6; range 0-8) and six (IQR 4-7; range 1-9), respectively, which were both higher (p = 0.0011 and p = 0.0000) than the World Cup competitors' scores. Ears back ≥ 5 s (p = 0.005), intense stare ≥ 5 s (p = 0.000), repeated tail swishing (p = 0.000), hindlimb toe drag (p = 0.000), repeated tongue-out (p = 0.003) and crooked tail-carriage (p = 0.000) occurred more frequently. These were associated with a higher frequency of lameness, abnormalities of canter, and errors in rein-back, passage and piaffe, canter flying-changes and canter pirouettes compared with World Cup competitors. There was a moderate negative correlation between the dressage judges' scores and the RHpE scores (Spearman's rho -0.66, p = 0.0002) at the British Championship. Performance and welfare may be improved by recognition and appropriate treatment of underlying problems.