Sudden death research yields clues
In a seven-year period, there were 201 cases of sudden equine death on British racecourses.
A research project on the risk factors associated with sudden death in racehorses has yielded some new information, according to the Royal (Dick) School of Veterinary Studies.
Veterinary surgeon, Catriona Lyle, took the lead in the multi-centre study after being awarded a three-year scholarship to study at the veterinary school.
Sudden equine death refers to any fatality occurring in a closely observed and previously healthy horse, either during or immediately after exercise.
Leading up to the study was the belief that if risk factors could be identified, this could help to reduce the occurrence of sudden death.
In a collaborative study, the research team used information from racecourses in North America, Japan, Australia and Hong Kong.
In the UK, post-mortems are not always carried out in sudden death cases, so access to international records was vital. The team studied postmortem data from 284 cases covering a 20-year period.
Commenting on the findings, Catriona said: "The study has shown that the cause of death can be quite variable, ranging from severe lung bleeding to a pelvic fracture that causes massive bleeding into the abdomen.
"But in approximately half the cases I studied, the pathologist was uncertain as to the cause of death. The most likely explanation for death in these situations is cardiac rhythm irregularities, but this is very difficult to prove."
After analysing international data, Catriona began studying cases involving British racehorses. In a seven-year period, there were 201 recorded cases of sudden death on British racecourses.
Analysing UK data, Catriona found increasing age to be a risk factor, while racing during summer was linked to increased risk of sudden death. Steeplechases were also thought to pose more of a risk than flat races, although it is also thought that steeplechasers are older, on average, than hurdlers or flat horses.
Welcoming the findings, chief veterinary officer for the British Horseracing Authority, Jenny Hall, referred to the project as "extremely useful".
"We are continuing to build on Catriona’s research with an ongoing investigation currently running at Britain’s northern racetracks," she said. "Sudden death is very distressing and we hope that owners will understand that allowing a full investigation into every racecourse death will help us reduce this risk."
BSAVA is to partner with BVA Live (11-12 June 2026) to champion clinical research.
