Postmortem findings in Ontario racehorses, 2003-2015.

The research article depicts a retrospective study on postmortem findings in Ontario racehorses from 2003 to 2015, where lesions and causes of death were examined. It is established that the most common cause of death was musculoskeletal injury and sudden death during or after exercise, often due to cardiopulmonary afflictions.

Objective and Methodology

• The study was retrospective in nature and aimed to evaluate postmortem lesions and causes of death in 963 horses amid a 13-year period.
• The study examined data from the Ontario Racing Commission Death Registry, which was established in 2003 to identify reasons leading to death or euthanasia of racehorses.
• A postmortem examination was carried out on 56% of horses reported to the Death Registry, including Standardbred, Thoroughbred, and American Quarter Horses.

Key Findings

• The most common cause of death associated with racing or training among all racehorses was musculoskeletal injury, accounting for 68% of cases.
• 31% of racing or training-associated deaths were reported as sudden death during or immediately following exercise, and this constituted 16% of all horse deaths in the study.
• Sudden death occurred across all horse breeds, with frequent attributions to cardiopulmonary lesions.
• 20% of sudden death cases put forth an undetermined cause of death, hypothesizing that cardiac arrhythmia may have contributed.
• Injection-associated death was reported in 4% of the study population.
• For deaths not related to exercise, gastrointestinal lesions were among the most common findings.

Recommendations and Conclusion

• The researchers suggested the standardization of pathology reporting of pulmonary and other lesions in racehorse postmortem cases.
• This standardization would allow direct comparison of results among different racehorse populations and contribute to the understanding of common health risks in racehorses.