Date Available

8-1-2024

Year of Publication

2023

Degree Name

Master of Science (MS)

Document Type

Master's Thesis

College

Agriculture, Food and Environment

Department/School/Program

Veterinary Science

First Advisor

Dr. James N. MacLeod

Abstract

Musculoskeletal injuries account for the majority of career-ending health concerns in Thoroughbred racehorses. A small but very serious subset of these can be life-threatening and usually involve fractures of the bones in the lower limb that occur during high-speed exercise or racing competitions. Understanding the etiopathogenesis of lower forelimb bone fractures leading to catastrophic musculoskeletal injuries (CMI) is the highest safety and welfare priority in horse racing. This thesis conducted two studies utilizing computed tomography (CT) images of Thoroughbred lower limbs. The first examined bone lesion annotations in 134 horses (268 forelimbs) across 105 anatomical sites to assess the concordance of lesion profiles. A series of pairwise comparisons were conducted utilizing a Hamming similarity metric to test the hypothesis that contralateral forelimbs exhibit high bone lesion concordance. The results strongly supported the hypothesis. Contralateral forelimbs displayed the highest level of lesion concordance in 101 instances, accounting for 37.69% of forelimbs within the population. While over half of the contralateral forelimbs (63.43% or 170 forelimbs) ranked within the top five positions based on Hamming similarity score rank. The second study assessed the degree of bone mineral density (BMD) adaptation of bones in the metacarpophalangeal (MCP) joint in response to the predictor variables age, gender, body weight, skeletal health, and recorded race starts. Samples used were categorized into four skeletal health groups corresponding to race training experience and primary cause of death. The hypothesis tested was that bones within the MCP joint of Thoroughbred racehorses exhibit concordant BMD changes in response to physiological modeling and remodeling. The results supported the hypothesis, but also identified interesting differences between bones that may be associated with disproportionate patterns of load and force distribution. Taken together, these studies contribute to the continuing efforts aimed at improving the safety and welfare of Thoroughbred racehorses and their riders.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2023.322

Funding Information

Spy Coast Farm

Lourie Family Foundation

August, 2021 – July, 2023

University of Kentucky, Department of Veterinary Science, Gluck Equine Research Center

Koller Emergency Response Fund

August, 2021 – July, 2023

University of Kentucky, Department of Veterinary Science, Gluck Equine Research Center

John S. and Elizabeth A. Knight Chair

August, 2021 – July, 2023

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