33 Assessing the effect of fatigue on stadium jumping penalty scores in elite three-day event horses utilizing artificial intelligence

Abstract

Mandatory veterinary inspections assess lameness and fatigue to help predict the success of performance horses during competition. Horses competing at the international level in 3-d eventing must pass both mandatory inspections (pre-competition and post-cross country) to attempt the final phase: stadium jumping. With this in mind we hypothesize that quantifying the gait quality of horses for fatigue during the inspections will help predict if they will have faults in stadium jumping. However, these pass/fail exams are based on subjective and non-repeatable guidelines referencing the locomotor function of the horse, and do not have the ability to detect small gait changes over time. The development of artificial intelligence-based video analysis approaches allows for the objective production of quantitative scores which can be used to accurately assess the physical capability of the equine athlete. We quantified our custom gait parameter pipeline using the software package DeepLabCut (DLC) of horses at the trot during the veterinary inspections and analyzed 197 horses across 3 levels (CCI-2*, CCI-3*, and CCI-4*) and 5 venues. We used a Quadratic Discriminant Analysis to assign a standardized coefficient score, which we noted as a fatigue score, to all horses. Utilizing 3 common fatigueparameters in a multivariate model using the row-wise method we found stride length (P < 0.001) and speed (P < 0.001) had significant negative correlation probabilities, and stance time (P < 0.001) had a significant positive correlation probability with the fatigue scores. The significance supports the idea that a higher fatigue score is indicative of greater fatigue in the horse. We then applied a qualitative label to each horse, faults or no faults, where a horse with no faults had zero time and zero jump faults, and a horse with faults had any combination of the 2. Then we compared the horse's fatigue score to the qualitative label and found that horses with faults had a significantly higher (P = 0.0149, standard t-test) fatigue score suggesting that fatigue may impact stadium jumping performance more than previously appreciated. Further work investigating the impact of locomotor phenotypes and fatigue on competition performance will encourage the use of objective measures to protect sport horse welfare and improve training strategies, as well as providing the opportunity to add an objective tool to the procedures for mandatory veterinary inspections.