Strongyle egg counts in Standardbred trotters: Are they associated with race performance?

Reasons for performing study: Strongyle worm burdens are assumed to subclinically affect equine performance. This assumption appears to be particularly pronounced in the equine racing industry. Hypothesis: Race results of Standardbred trotters are negatively affected by high strongyle faecal egg count levels. Methods: Faecal samples were obtained from 213 racing Standardbred trotters, aged ≥2 years, and stabled at training facilities of 21 professional trainers with license at racecourses in Denmark. Strongyle egg counts were generated using a McMaster technique. Race results were recorded as the finishing position of the horse (position 1-3 vs. finishing lower) and winning purse. The effect of strongyle egg counts on performance was assessed using regression analyses. Results: Strongyle egg counts ranged from 0-3500 with a mean of 319 and a median of 150 eggs/g. Finishing in positions 1-3 was significantly associated with higher egg counts. Conclusions: Race performance of the population of professionally trained Danish Standardbred trotters was not negatively affected by higher strongyle faecal egg count levels. Potential relevance: The traditional frequent anthelmintic treatments of racehorses may be inordinate.