Background: Athletic performance of horses is of economic importance in equine industry; thus, several studies have been conducted in order to identify the contributing factors in this regard. Limited information, however, is available on whether prenatal factors could impact athletic performance of horses.
Objectives: The present retrospective study, therefore, was conducted to investigate the association of maternal and paternal age and sex ratio with offspring athletic performance in horses.
Methods: Initially, the association of maternal and paternal age with maternal and paternal sex ratio was analyzed in the primary dataset consisting of 4200 offspring. For further analysis, only offspring of dams and sires that had at least four offspring and racing records of 1000 m and 1600 m distances were used. As a result, the dataset used for analyses concerning athletic performance consisted of 1244 offspring, which had cumulatively 11083 racing records.
Results: Proportion of male offspring decreased by increase in paternal age (P < 0.05), but it was not associated with maternal age (P > 0.05). Frequency of racing events during athletic lifetime of offspring decreased by increase in maternal age (P < 0.05), but it was not associated with paternal age (P > 0.05). Age at first racing decreased as paternal sex ratio skewed towards males (P < 0.05); however, it was not associated with maternal sex ratio (P > 0.05). In racing distance of 1000 m, racing record time increased and risk of winning one of the first three places in racing decreased by increase in maternal and paternal age (P < 0.05). In racing distance of 1600 m, risk of winning one of the first three places in racing increased as paternal sex ratio skewed towards males (P < 0.05), but it was not associated with maternal sex ratio (P > 0.05).
Conclusion: In conclusion, the present study showed that maternal and paternal aging could have negative effects on athletic performance of the resultant offspring. Paternal sex ratio, moreover, appeared to be associated with offspring athletic performance, particularly in racing distance of 1600 m.