The effect of neonatal dysphagia on subsequent racing performance in Standardbred horses

BACKGROUND Previously we described a clustering of dysphagic foal cases on a Pennsylvania (PA) Standardbred farm which was associated with exposure of pregnant mares to high concentrations of polycyclic aromatic hydrocarbons (PAHs) in the well water [1,2]. The effect of dysphagia on future athleticism was uncertain. OBJECTIVES To determine if, as adults, dysphagic foals were less likely to race and if athleticism (age of first race, Speed Index, Earnings Per Start Index) differed from that of healthy foals that raced as adults. STUDY DESIGN Prospective cohort study. METHODS All foals born during the study period (2014-17) on the affected PA or an unaffected New York (NY) farm with the same proprietor were eligible for inclusion in the study. Foals with dysphagia attributed to causes other than PAH environmental exposure were excluded. The proportion of foals from both farms that raced, their age of first race, Earnings Per Start Index and Speed Index, were compared between the dysphagic and normal foals using Chi-Square and Wilcoxon Rank Sum Tests. Significance level was p 0.05. MAIN LIMITATIONS Small sample size and unique type of dysphagia. CONCLUSIONS The athleticism of formerly dysphagic foals does not appear to be negatively impacted compared to normal foals as measured by age of first race, Earnings Per Start Index and Speed Index.