Equine gait-related eliminations in British endurance: Identifying risk factors to improve horse welfare

Introduction: Endurance is an equestrian sport where horse and rider combinations compete up to 160km in one day. In order to be successful within competition, horses must pass a metabolic and gait assessment by licenced veterinarians, not only at the start, but during and at the end of the competition. If they fail this inspection they are eliminated from competition. Lameness has been identified as the leading cause of elimination in studies of international-level competition but had not been evaluated in British Endurance.Aim: To identify risk factors for lameness eliminations in British national competition, including details such as which limb(s) are most frequently identified as lame.Methods: A retrospective epidemiological study followed by two prospective studies were conducted. First, competition data recorded by Endurance GB were analysed. Univariable analysis was used to inform two multivariable binary logistic regression models with the dichotomous variables pass/did not pass and lame/ not lame. These results informed the design of the prospective studies. The first determined whether there were significant differences between forelimb and hindlimb eliminations. The second prospective study investigated thoracolumbar back pain on palpation and tested inter-rater reliability of veterinary inspections for limb identification, lameness grade and epaxial muscle palpation.Results: Retrospective study: Risk factors identified as significant (P<0.05) in the final multivariable models included historic cumulative distances attempted, historical number of starts, eliminations and specifically lameness eliminations. Prospective studies: Technicality of the course in terms of steepness was an additional risk factor for single loop rides, whereas it was not for multi- loop rides. Increased average speed was a risk factor in multi-loop rides. Hindlimb lameness was identified more frequently than forelimb lameness. Asymmetrical back palpation was a significant risk factor for elimination and lameness across all distances. Inter-rater reliability of limb identification was excellent with 100% agreement between the assessors when two veterinarians were used (K=1, p<0.001, C.I.0.86-1.14) and remained excellent when three veterinarians identified the lame limb (K=0.83, p