Horse-, training- and race-level risk factors for palmar/plantar osteochondral disease in the racing Thoroughbred.
Authors: Pinchbeck G L, Clegg P D, Boyde A, Barr E D, Riggs C M
Journal: Equine veterinary journal
Summary
Palmar/plantar osteochondral disease remains a significant welfare and economic concern in racing Thoroughbreds, yet the specific training and racing protocols that precipitate or exacerbate the condition have been poorly characterised. Pinchbeck and colleagues examined the metacarpo/metatarsophalangeal joints of 164 racehorses post mortem, grading osteochondral disease across 1,288 condyles and correlating these findings with detailed racing and training histories using multilevel logistic regression analysis. Higher disease grades were significantly associated with cumulative lifetime race numbers, increased gallop sessions in the preceding season, and frequent short between-race intervals (8–16 weeks per season)—supporting the hypothesis that repetitive loading drives disease severity. Conversely, longer recovery periods between races (>16 weeks) and extended time away from racing (up to 400 days) were protective factors associated with lower grades, suggesting that lesions may be capable of partial remodelling with adequate rest. These findings have direct implications for training schedule optimisation: practitioners should consider spacing races more strategically to allow tissue recovery rather than clustering races into short intervals, whilst recognising that cumulative lifetime racing exposure creates a dose-dependent disease burden that cannot be fully mitigated through scheduling alone.
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Practical Takeaways
- •Cumulative racing exposure is a primary driver of POD severity; managing total lifetime race numbers and preventing excessive racing early in a horse's career may reduce disease progression
- •Implement longer recovery periods between races (>16 weeks when possible) and reduce high-intensity gallop sessions in pre-race training to minimize POD development and potentially allow lesion healing
- •Rest periods are beneficial—horses with ≥400 days since last race showed lower POD grades, suggesting that strategic breaks in racing schedules may allow joint remodeling and recovery
Key Findings
- •Total lifetime number of races was associated with higher grades of POD in Thoroughbred racehorses
- •Increased gallop sessions in the previous season and racing before import to Hong Kong were associated with higher POD grades
- •Short between-race intervals (8-16 weeks) per season increased POD severity, while longer intervals (>16 weeks) and increased time since last race reduced severity
- •Age at first race was not significantly associated with POD grade, contradicting the hypothesis that early racing increases disease severity