Risk Factors for Jockey Falls in Japanese Thoroughbred Flat Racing

Plasma Non-targeted Metabolomics Analysis of Yili Horses Raced on Tracks With Different Surface Hardness

In this study, the plasma non-targeted metabolomics of Yili horses were characterized before and after exercise on tracks that differed in surface hardness to better understand exercise-related biochemical changes. Blood samples were obtained from eight trained Yili horses before and immediately after exercise. Samples were used for metabolomic analysis by ultra-performance liquid chromatography-Q-EXACTIVE mass spectrometry. In total, 938 significantly different metabolites involving sugar, lipid, and amino acid metabolism were detected in the plasma, with significant increases in glucose, glucoheptanoic acid, lactic acid, malic acid, and methylmalonic acid and significant decreases in creatinine, D-tryptophan, carnitine, and citric acid after exercise. Among these metabolites, acetylcarnitine, tuliposide, vitamin C, and methylmalonic acid showed regular changes in concentration after exercise on tracks that differed in surface hardness, providing new insights into equine exercise physiology. The findings indicated the potential of vitamin C and methylmalonic acid as novel biomarkers of equine locomotor injury.

The Impact of Circular Exercise Diameter on Bone and Joint Health of Juvenile Animals

Circular exercise is used in many equestrian disciplines and this study aimed to determine if circle diameter impacts juvenile animal forelimb bone and joint health. On day 0, 24 calves at 9 weeks of age were assigned the following exercise treatments: small circle (12 m clockwise), large circle (18-m clockwise), treadmill, or non-exercised control. Exercise was initiated at 1.1−1.5 m/s for 5 min/d and increased 5 min weekly until reaching 30 min/d. On day 49, synovial fluid was collected from multiple joints, cartilage was collected from the proximal surface of fused third and fourth metacarpi (MC III and IV), and forelimbs underwent computed tomography scans. A statistical analysis (PROC mixed) was performed in SAS 9.4. The inside leg of the small circle treatment had a larger MC III and IV dorsopalmar external diameter than the outside (p = 0.05). The medial proximal phalanx had a greater mediolateral diameter than the lateral proximal phalanx of the small circle treatment (p = 0.01). Fetlock nitric oxide was greater in the large circle and treadmill treatments (p < 0.0001). Cartilage glycosaminoglycan concentration was greater in the outside leg of the small circle exercise treatment than the inside leg (p = 0.03). Even at slow speeds, circular exercise diameter can impact joint and bone health, but faster speeds may have greater alterations.

Impact of Gait and Diameter during Circular Exercise on Front Hoof Area, Vertical Force, and Pressure in Mature Horses

Circular exercise can be used at varying gaits and diameters to exercise horses, with repeated use anecdotally relating to increased lameness. This work sought to characterize mean area, mean vertical force, and mean pressure of the front hooves while exercising in a straight line at the walk and trot, and small (10-m diameter) and large circles (15-m diameter) at the walk, trot, and canter. Nine mature horses wore TekscanTM Hoof Sensors on their forelimbs adhered with a glue-on shoe. Statistical analysis was performed in SAS 9.4 with fixed effects of leg, gait, and exercise type (PROC GLIMMIX) and p < 0.05 as significant. For all exercise types, the walk had greater mean pressure than the trot (p < 0.01). At the walk, the straight line had greater mean area loaded than the large circle (p = 0.01), and both circle sizes had lower mean vertical force than the straight line (p = 0.003). During circular exercise at the canter, the outside front limb had greater mean area loaded than at the walk and trot (p = 0.001). This study found that gait is an important factor when evaluating circular exercise and should be considered when exercising horses to prevent injury.

Risk factors for jockey falls in Japanese Thoroughbred jump racing

Jockey safety is an important subject from a welfare perspective and public perception. This is the first retrospective case-control study that aims to identify risk factors associated with jockey falls (JF) in Thoroughbred jump races held by the Japan Racing Association (JRA). JF in 17,459 maiden-class race starts at eight racecourses from 2003 to 2017 were retrospectively reviewed. Data were extracted from a database and official accident reports maintained by the JRA. Thirteen possible risk factors were evaluated using multivariable logistic regression to identify those that were significantly associated with JF. A total of 724 JF were recorded, with an incidence rate of 41.5 falls per 1,000 starts (95% CI: 38.6-44.5). Final model included stable, horse age, year, season, course, horse sex, horse experience, and jockey experience. No two-way interactions were observed. Six risk factors were significantly associated with JF: Year (2003-2007 or 2008-2012 > 2013-2017; P = .0011), season (spring, autumn, or winter > summer; P = .0006), course type (dual direction > single direction; P < .0001), horse sex (female > male or gelding; P = .0003), horse experience (inexperienced horse > experienced horse; P < .0001) and jockey experience (apprentice jockey > experienced jockey; P = .0332) significantly affected the odds of JF. In agreement with overseas reports, our results suggest that the occurrence of JF is multifactorial and associated with jockey- and horse-related factors as well as environmental factors. To safeguard the welfare of jockeys, implementation of measures according to identified risk factors is recommended.