Descriptive epidemiology of veterinary events in flat racing Thoroughbreds in Great Britain (2000 to 2013)

Abstract

Background: To date, no large scale studies have reported race-day events requiring veterinary attention in British Thoroughbreds racing on the flat. Quantifying and describing common injuries and health conditions affecting racehorses will enable targeted risk factor analysis aimed at reducing their occurrence.

Objective: To describe the type and incidence of race-day veterinary events experienced by Thoroughbred racehorses participating in flat racing in the UK.

Study design: Retrospective cohort study (2000 to 2013).

Methods: Veterinary events recorded by race-day veterinarians were retrieved and linked to race start data. Race-day veterinary events were described by type, location and anatomical structure(s) affected and whether the outcome was fatal or not. Incidence per 1000 starts was calculated, both overall and by year. Stratified incidence rates were calculated for selected event categories by specific course- and horse-level variables.

Results: There were 7993 events experienced by 6727 horses, with an incidence of 9.37 events per 1000 starts. Soft tissue injuries other than tendon and ligament injuries were the most commonly occurring veterinary events (24.1%), followed by gait observations (21.2%) and respiratory conditions (21.2%). In total, 13.8% of events were bone injuries. The incidence of fatality (n = 628) was 0.76 per 1000 starts. Most (485/628, 77.2%) fatal events were bone injuries, 64 were due to cardiac conditions and 54 due to tendon and ligament injuries. All-weather tracks had a higher incidence of veterinary events and fatalities than turf tracks. Firmer (turf) or faster (all-weather) going were associated with a higher incidence of all veterinary events.

Main limitations: Events were based on presumptive, rather than definitive, veterinary diagnosis.

Conclusion: The most common events experienced by racehorses on race-day were relatively minor and not career-ending. Although more severe bone, joint, tendon and ligament injuries were less common, they had a greater impact on whether the outcome of the event was fatal.

Keywords: epistaxis; fatalities; fractures; horse; incidence rates; injuries; racehorse.