Incidence of exertional rhabdomyolysis in polo horses in the USA and the United Kingdom in the 1999/2000 season.

This study explores the incidence of exertional rhabdomyolysis – a muscle disorder – in polo horses across the USA and UK for the 1999/2000 season, finding an overall rate of 7.3%. The research identifies several contributing factors including horse temperament and insufficient fitness levels for the game intensity.

About the Study

This research used a questionnaire to:

• Gauge the incidence of exertional rhabdomyolysis
• Identify potential contributing factors for its occurrence

The researchers examined a sample of 423 polo horses spread across 11 randomly selected yards, six located in north-eastern USA and five in south-east England.

Key Findings

The findings highlighted that:

• The overall incidence rate was 7.3% during the 1999/2000 season
• The US prevalence rate was 9%, while England had a lower rate at 6.7%
• Incidence rates between mares were similar in both countries at 8.4% for the USA and 8% for English horses
• Geldings in the USA exhibited a much higher incidence rate of 10% compared to only 1.5% in the UK

Contributing Factors

• Exertional rhabdomyolysis was found to be more prevalent in horses with more excitable temperaments, constituting 71% of cases
• Most cases occurred when the horse was deemed not fit enough for the level of polo being played, particularly noted after a game or ‘chukka’
• A significant 64% of cases were found early on in the season

Impact on Training

The research found that, on average, each episode of exertional rhabdomyolysis resulted in the loss of 7.6 training days. This poses significant implications for polo training schedules and the potential need for adaptive conditioning and management practices for horses prone to this condition.