An Australian survey found that euthanasia for catastrophic forelimb injury was the most common Thoroughbred racehorse fatality. Also, sudden death (not as the result of euthanasia) contributed more to racing fatalities than previously thought. Analyzing point-of-death blood samples could help scientists better pinpoint the triggers of sudden deaths.

Lisa Boden, AB, BVSc, MACVS, a PhD candidate at the University of Melbourne, and colleagues documented injuries that either caused sudden death or required euthanasia (within 24 hours of injury) during the three-year study.

Seventy-seven of 180 (43%) deaths in Victoria during the study were evaluated. In those 77 horses, 31 fatal injuries (40%) were sustained in flat races, 25 (32%) in track or non-raceday events, 19 (25%) in jump races (hurdle and steeplechase events), and two in barrier trials (qualifiers, 3%). Fifty-two were euthanatized and the remaining 25 died suddenly.

Most of the horses were males (61, or 79%); of those, 56 (92%) were geldings. Most fatalities involved euthanasia after a catastrophic forelimb injury (similar to results of studies in other countries). Catastrophic injuries to the front cannon or hind cannon were the most common, followed by cannon injuries accompanied by fractures of the proximal sesamoids and the first phalanx (the long pastern bone)