Ability of clinicopathologic variables and clinical examination findings to predict race elimination in endurance horses.

The research aimed to identify risk factors for endurance horse race elimination by comparing results from point-of-care laboratory testing and standard veterinary clinical examinations. The study found that a combination of breed, clinical and lab results best predicted race elimination risks.

Objective and Animal Study Base

• The aim of the research was to compare the results of point-of-care laboratory testing and traditional veterinary clinical examinations to identify horses at risk of being eliminated from an endurance competition. The study was conducted on 101 horses participating in the 2013 Western States 160-km (100-mile) endurance race.

Procedures Followed

• At the 58-km checkpoint, blood samples from all participating horses were collected. These samples were tested for various factors including pH, Pco, base excess, anion gap, PCV, and whole blood concentrations of sodium, potassium, chloride, total carbon dioxide, BUN, glucose, and bicarbonate. Corrected electrolyte and PCV values were also calculated considering the plasma total protein concentration.
• Every horse underwent a clinical examination after the blood sample was taken. An adjusted heart rate was determined based on the time difference between arrival at the checkpoint and the recording of the heart rate.

Analysis and Prediction Method

• A combination of methods was used to identify variables associated with overall race elimination or one of three distinct elimination categories (metabolic elimination, lameness elimination, and elimination due to other reasons). These methods included stepwise logistic regression, classification and regression tree analysis, and generalized additive models.

Results of the Study

• The results indicated that corrected whole blood potassium concentration and adjusted heart rate were predictive for overall elimination.
• Breed, plasma total protein concentration, and the horse’s attitude were found to be predictive for elimination due to metabolic reasons.
• Whole blood chloride concentration and corrected PCV were found to be predictive for elimination due to lameness.
• Corrected PCV also was predictive for elimination for other unspecified reasons.

Conclusions and Clinical Relevance

• The study concluded that for endurance horses, a mixture of breed, clinical examination data, and laboratory variables provided the best prediction model for overall race elimination. These findings could help inform practitioners and trainers on the most effective methods for predicting race performance, preventing injury, and ensuring horse welfare during endurance competitions.