Effects of racing on equine fertility.

This research explores the correlation between horse racing and the fertility rates in those horses. The findings suggest that while stress from racing may impact the fertility of mares negatively, the right nutrition and management of a racing horse could have positive effects, while racing has no apparent negative impact on stallion fertility.

Research Method

• The data used in this research were mating records of Finnish Standardbreds and Finnish horses from the years 1991 to 2005 and the harness racing records of both mares and stallions.
• Fertility was measured through the outcome of foaling, while the performance in racing was evaluated based on the best time in races and the number of races participated in by the horses.
• The researchers considered racing outcomes from both the mating year and the entire career of the horses to study the short-term and long-term impacts of racing on equine fertility.
• A linear mixed model is utilized in analysis, in which racing was fitted as a fixed factor.
• The investigation into the genetic association between racing and fertility was conducted separately by applying a threshold model for the fertility trait.

Research Findings

• Racing after the first mating or more than 10 times during the mating year can negatively impact the foaling outcome in mares. But racing before the first mating or 1-5 times within the mating year could positively impact the fertility of mares.
• Stallion fertility does not appear to be negatively affected by racing in the mating year.
• Mares with the best career racing records had the highest foaling rates. However, the researchers propose that this may be a result of these horses receiving preferential treatment, implying selection bias.
• The genetic association between the best racing record and fertility was found to be weak and favorable in the Finnish horse (-0.24±0.08), while negligible in the Standardbred (-0.15±0.11).

Conclusion and Implications

• The research concludes that there is a correlation between horse racing and equine fertility, but it’s complex and influenced by different variables. Stressful racing can have some negative impacts on fertility in mares, yet racing under ideal management and nutrition conditions can enhance fertility.
• Interestingly, the fertility rates in stallions participating in horse racing does not seem to be affected negatively, providing a strong point for further investigation into the divergent effects of racing on different genders.
• The results also draw attention to the role of management practices in horse racing, illustrating the benefits of good nutrition, appropriate stress management, and judicious control of racing frequency.