FRANK J. MILNE STATE-OF-THE-ART LECTURE


Skeletal Injuries in Equine Athletes – Pathogenesis and Training Concepts for Injury Prevention


Susan Stover, DVM, PhD, DACVS


Author’s address: University of California-Davis, School of Veterinary Medicine, One Shields Avenue, Davis, CA 95616; e-mail: smstover@ucdavis.edu. © 2022 AAEP.


1. Introduction


While it is rewarding to successfully diagnose and treat an individual horse for an injury and see the horse return to performance, it is equally rewarding and possibly more impactful to use knowledge and ex- pertise to help clients train their horses to optimize performance with low risk for injury. This paper is a brief reminder that the impact of skeletal injuries on horse attrition and industry costs; then builds the foundation for understanding the need for skeletal ad- aptation to sport horse demands, the mechanisms for injury and adaptation, and the contributing factors to sport horse injuries; and lastly reviews concepts of training to shift the balance to adaptation and optimal performance.


2. Cost of Poor Performance and Attrition


effects on industry economics.2 As an example, median financial return was $23,000 less for yearling Thorough-


NOTES


The cost of poor performance, inability to perform, and attrition fromequine sport can be huge. Musculoskeletal injuries have a large detrimental impact on the sport horse industries. Injuries result in loss of horses from training and racing, racehorse deaths, jockey injury and deaths, and poor public perception of the racing industry. Inability to train racehorses in New York occurred for 8.1% of potential training days, 72.1% due to lameness.1 Insidious, but devastating, outcomes include the adverse


bred horses being broke and conditioned for 2-year-old in-training sales that lost 13 to 108days of training com- pared to horses that lost only 1 to 11days of training.3 Economic wastage in 2011 was estimated at almost $3 million each month in California racehorses and over $81 million per month nationally, based on ;3% of horses lost from racing eachmonth andmedian yearling auction price.a The estimate does not include costs associated with training, treatment, rehabilitation, shoeing, and other expenses to prepare and keep horses in training and competition. High turnover of sport horses results in poor return on owner invest- ments. Consequently, elucidating and managing the causes of skeletal injury should be key goals of the sport horse industries.


3. Skeletal Adaptation


The skeleton is an energetically expensive part of the body. Mineralization imparts bones with the neces- sary stiffness and strength to support the body and allow for locomotion. However, mineralized tissues are dense and heavy and thus energetically expensive to carry and move. Consequently, the skeleton is dynamic and continually adapts, gaining or removing bone material in response to the most recent loading (exercise) conditions. The process is analogous to gain- ing or losing muscle mass with exercise or inactivity, respectfully.


AAEP PROCEEDINGS / Vol. 68 / 2022 95


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