Training-related factors associated with dorsometacarpal disease in young Thoroughbred racehorses in the UK.

The research examines the occurrence rates and contributing factors of dorsometacarpal disease (DMD) in Thoroughbred racehorses in the UK and highlights the link between the disease and the horses’ training regimens.

Objective and Methods

• The main objective of the research was to estimate DMD’s incidence rate among Thoroughbred horses undergoing training for flat racing in the UK and discover any associated risk factors, particularly those linked to their training schedules.
• For this study, data was gathered from a vast prospective study which monitored 13 training yards where Thoroughbred horses were kept. The study was conducted over a period of two years.
• In this period, daily training information was recorded along with details of any musculoskeletal injuries, including DMD.

Results and Observations

• During the surveillance period, 335 horses provided a cumulative 4235 months at risk of DMD.
• Throughout this period, 79 first episodes of DMD were recorded, hence leading to an incidence rate of 1.87/100 horse months.
• Surprisingly, a pattern emerged from the data, showing an increasing risk of DMD with single short bursts of increasing exercise distances at higher speeds (up to 1 month).
• However, contradictorily, the study also found that with the gradual increase in cumulative exercise distances from the start of their training, horses were found to have a decreasing risk of contracting DMD.

Conclusions

• These results suggest that the risk of contracting DMD in young Thoroughbreds decreases with a gradual accumulation of distances exercised at canter and high speed, indicating that the third metacarpal bone adapts to the loads put upon it.
• The study also indicates that the risk of DMD is increased with hasty increasing exercise distances in short periods – possibly due to microdamage and a related remodelling response. Therefore, this practice is advised to be avoided.
• The researchers concluded that to avoid DMD, training regimens for young Thoroughbreds could be adjusted by incorporating an early and gradual introduction of small amounts of high-speed exercises.
• Additionally, on high-speed work days, canter exercise should be kept minimal, and large amounts of both cantering and high-speed work per week or per month should be avoided, especially in the early training stages.