Thoroughbreds deemed to be most at risk by inertial measurement unit sensors suffered a fatal musculoskeletal injury at a higher rate than other racehorses.

Overview

• This study investigated whether accelerometer-based inertial measurement unit (IMU) sensors and a predictive algorithm can identify Thoroughbred racehorses at highest risk of fatal musculoskeletal injury (FMI).
• The research also examined how factors like age, gender, race distance, and track surface relate to the risk of fatal injury.

Study Objective and Design

• Purpose: To determine if a sensor-based screening method can effectively identify Thoroughbred racehorses at greatest risk for FMI.
• Data Collection: Stride data was collected from 28,481 races involving 11,834 Thoroughbred horses over nearly three years, from July 25, 2021 to May 4, 2024.
• Data Processing: Each horse’s data was assigned a risk score between 1 and 6 by an algorithm trained to predict FMI risk, with 6 indicating the highest risk.
• Statistical Analysis: Logistic regression models assessed associations between fatal injury incidence and risk score, as well as other factors including gender, age, race distance, and track surface.
• Additional comparisons across groups were made using a Tukey adjustment to account for multiple comparisons.

Key Findings

• Fatal Injuries: During the study period, 74 horses suffered fatal musculoskeletal injuries.
• Risk Score Correlation: There was an exponential relationship between the risk score assigned by the algorithm and the probability of FMI.
• High Risk Group: Horses with a risk score of 6, though accounting for only 0.4% of race starts, contributed to 4% of fatal musculoskeletal injuries, indicating a disproportionate risk.
• Relative Risk: These highest-risk horses were 44.6 times more likely to sustain a fatal injury than horses with the lowest risk score of 1.
• Age Factor: Age was not found to be a significant factor associated with increased risk for fatal injury.
• Gender Factor: Male horses had a higher risk of fatal musculoskeletal injury compared to females.
• Race Distance: Horses racing shorter distances showed a greater risk of sustaining fatal injuries.
• Track Surface: Fatality rates were higher on dirt and turf tracks compared to synthetic all-weather surfaces.

Conclusions and Implications

• Validation: The IMU-based risk scoring algorithm successfully identified horses at significantly greater risk for fatal musculoskeletal injuries.
• Practical Applications: Implementing this screening tool could allow veterinarians and trainers to identify at-risk horses before injury occurs.
• Recommended Follow-up: Horses flagged as high risk (score of 6) should undergo thorough lameness examinations and advanced diagnostic imaging to detect early signs of musculoskeletal problems.
• Potential Impact: Early identification and management of at-risk horses could lead to a reduction in fatal injuries, improving animal welfare and safety in racehorse populations.