Oral Presentation 24th International Conference of Racing Analysts and Veterinarians 2026

Abnormalities in the Suspensory Apparatus of Thoroughbred Fatalities in Kentucky Racetracks (130173)

Fernando Mosquera Jaramillo 1 , Stefanie Coates 2 , Claire Duval 1 , James N MacLeod 1 , Stacey A Slone 3 , Emma N Adam 1 , Laura Kennedy 4 , Bruno C Menarim 1
  1. Gluck Equine Research Center, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA
  2. College of Veterinary Medicine, Lincoln Memorial University, Harrogate, Tennessee, USA
  3. Dr. Bing Zhang Department of Statistics, University of Kentucky, Lexington, Kentucky, USA
  4. Veterinary Diagnostic Laboratory, Martin-Gatton College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA

Musculoskeletal injuries are the leading cause of racehorse retirement and death translating into a significant welfare concern and threats to horseracing’s social licence to operate. Catastrophic musculoskeletal injuries (CMI) account for more than 65% of the racehorse deaths at Kentucky racetracks. The suspensory apparatus and fetlock joints are the most common sites of injury (>80% of cases). The aim of this study was to describe the anatomical distribution and magnitude of macroscopic abnormalities in the suspensory apparatus (SA) of Thoroughbreds from the Kentucky Horseracing Postmortem Program. We hypothesized that suspensory apparatus lesions are present in both forelimbs in CMI- and non-CMI racehorses in training and racing.
Complete suspensory apparatuses were collected from 66 Thoroughbred racehorse fatalities in Kentucky during 2023 (41 CMI; 25 non-CMI; 132 total SA). Suspensory apparatuses were sectioned at 11 levels. The cross-sectional areas (CSA) were evaluated using digital image analysis (Photoshop, 2025). Fatally injured SAs were excluded due to acute tissue alterations. Data analysis was performed using median area of abnormal tissue coloration and counts of abnormal areas per section using multivariable logistic regression.
Suspensory apparatus failure was the reason for euthanasia in 80% of CMI horses. Moderate and severe abnormalities were detected in at least one section of 78 SAs (44/50 [88%] non-CMI; 26/33 [78%] CMI contralateral limbs; 8/16 [50%] of non-CMI). The most common sites of abnormalities in all groups were distal sesamoidean ligaments (DSL, 75.7%) and suspensory ligament branches (56%).
Noticeable abnormalities were observed in the SAs of most horses in this study regardless of having started in a race. Of note, is the incidence of abnormalities identified in the non-CMI group in this study. Findings from this and the previous studies suggest that SA, especially branches and DSLs, are anatomical areas that warrant additional monitoring in racehorses racing and in race training.