Extensive blood in the lungs and abdominal bleeding due to rupture of a large blood vessel were present in several eventing horse fatalities, a researcher reports.
Dr Catherine Kohn, a specialist in internal medicine and a professor in the Department of Clinical Sciences at The Ohio State University School of Veterinary Medicine, is part of a research group looking for the reasons for these hemorrhagic events.
Traumatic bone, soft tissue, and brain injuries have also been documented in eventing horse fatalities, she said.
Kohn has provided an update on the US Eventing Association’s website on the work of its Cardiopulmonary Research Group.
The group is exploring risk factors for fatalities in eventing horses during competition in the hope that strategies can be devised to reduce the risk.
Recent field studies by the group explored whether irregular heart rhythms, not present at rest, might occur during the cross-country phase.
The researchers collected data using a recording system fitted to each horse. Recordings of the electrical activity of the heart from 124 horses competing in a cross-country test were collected across all levels of competition in five US states.
Sixty percent (75) of the 124 recordings were good enough to be interpreted, with roughly half from lower-level classes and the rest from higher-grade competitions.
“Our initial review did not reveal cardiac arrhythmias that would impair the safety of horses in competition,” she reported.
“We have identified, in several horses, arrhythmias that are not considered a threat to safety,” she said, adding that their impact on performance was not yet known.
She stressed that evaluations to date were preliminary, and in-depth work may lead to revised findings.
Kohn said that the group recommended that a veterinarian carefully listened to a horse’s heart before their first eventing competition.
“If the horse’s heart rhythm is normal, and there are no heart murmurs, schedule annual reevaluations to ensure that heart function continues to be normal.”
Horses with a detected abnormality in heart rhythm or a heart murmur should be evaluated by a veterinary specialist with experience and advanced training in equine cardiology, she said. This should include an electrocardiogram and an echocardiogram.
A stress test, in which heart function is assessed during exercise, might prove necessary, she said.
“The goal of these examinations is to be as certain as possible that your horse is not at risk for having performance or life-limiting reductions in cardiac function while competing. In other words, we want to help you to prevent high-risk horses from competing.”
Kohn said the importance of performing post mortem evaluations of all horses that died during competition or within the week following the event could not be overstated.
“So far, we have learned that extensive pulmonary hemorrhage (blood in the lungs) and abdominal bleeding (due to rupture of a large blood vessel) were present in a number of these fatalities.”
She said the research group wanted to examine tissue samples from lungs, heart and blood vessels to look for a cause for these bleeding events.
It was, she said, essential that as much as possible was learnt from each horse that died in eventing.
“We encourage trainers, riders and owners to agree to a necropsy for any horse that dies during competition or within seven days of competing.” (Specific details can be found here.)
More information can be found here.