• 19 February 2014

Clues into Sudden Equine Death Revealed

In an attempt to gain some understanding of this devastating, but fortunately extremely rare occurrence, the Horserace Betting Levy Board recently funded a three-year scholarship at the University of Edinburgh's Royal (Dick) School of Veterinary Studies.

The HBLB took the lead in a multi-centre study into the sudden death of racehorses in the hope of finding ways to reduce the likelihood of it happening, and to identify the risk factors involved.

By its very nature and definition, Sudden Equine Death is challenging to investigate, involving the sudden and unexplained death of a closely observed and previously healthy horse, either before, during, or immediately after exercise.

The Dick Vet has been at the forefront of equine research for some considerable time, and is very proud of its history in working with partners across the industry. The scholarship was awarded to Catriona Lyle, a vet who studied at Dick with Professor Bruce McGorum (Head of Equine Sciences), Dr Lisa Boden and Dr Tim Parkin. Her pioneering study is yielding some clues into the provenance of Sudden Equine Death.

For the study to be beneficial, it was essential for Catriona to have access to international records, since post mortems are not always carried out in the UK in the case of sudden death. She was able to coordinate a collaborative study of information from racecourses in North America, Australia, Japan and Hong Kong, bringing together data from 284 cases over a 20-year period. Following her analysis of these international incidences, she then studied the 201 sudden deaths on British racecourses that occurred over a seven-year time frame, from almost 3/4 million starts.

Catriona explained some of the findings: "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. However, 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."

Although the same syndrome is known to occur in the equine disciplines of eventing, showjumping and hunting, there are no statistics available at present. However, it has been estimated that around 5% of horses in the general equine population, of a similar age to racehorses, die each year due to illness or injury. Of these, approximately 5% of deaths are accounted for by cardiac disease, and older horses are, of course, far more prone to cardiovascular related death.

Indeed, in the study of UK deaths, Catriona found that a risk factor was certainly increased age, likewise steeplechasing posed more of a risk than flat-racing. There was a greater incidence of sudden death associated with summer racing. However, it must be remembered that, generally, steeplechasers are older than hurdlers or flat racers.

The British Horseracing Authority is continuing to build on Catriona's research by maintaining an ongoing investigation at Britain's Northern racetracks.

Chief Veterinary Officer of the BHA, Jenny Hall said, "This was an extremely useful project. 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 the risk."

Chairman of the BHLB Veterinary Advisory Committee, Professor Willie Donachie, was generous in his praise of Catriona and her research, "Not only did she complete two major studies on sudden death, where her results will pave the way to reducing this problem, but she also passed her European Diploma exam; a fantastic set of achievements in only three years"

w. www.beva.org.uk