Horse Tying-Up Prevention: Managing Equine Rhabdomyolysis Syndrome

Tying-up, or exertional rhabdomyolysis, causes severe muscle pain in horses during or after exercise. Prevention through diet, management, and exercise modifications dramatically improves equine welfare.

Key Facts

Tying-up describes a syndrome of muscle cramping and myoglobin release during or after exercise
Recurrent Exertional Rhabdomyolysis (RER) is common in Thoroughbreds and has a genetic component
Polysaccharide Storage Myopathy (PSSM) causes tying-up in Quarter Horses and draft breeds through glycogen accumulation
An affected horse shows severe hindquarter pain, sweating, reluctance to move, and dark urine
Diagnosis involves blood testing for elevated CK and AST enzyme levels and muscle biopsy
Dietary management is central to prevention: low-starch, high-fat diets reduce incidents in PSSM horses
Regular exercise without days of rest followed by sudden intense work reduces RER episodes
Electrolyte imbalances, particularly sodium and selenium deficiency, can trigger episodes

Welfare Considerations

Tying-up causes intense, acute muscle pain that is visible in affected horses as profound distress - sweating, trembling, reluctance to move, and obvious agony. Severe cases can cause kidney damage from myoglobin release. Horses experiencing severe episodes should be treated as genuine emergencies. The welfare tragedy is that many episodes are preventable with appropriate dietary management and exercise protocols. Horses with known genetic predisposition (RER or PSSM) can live normal working lives with proper management. The problem is that these conditions are underdiagnosed and preventive management is inconsistently applied, meaning horses suffer repeatedly when management changes could eliminate or dramatically reduce episodes.

What You Can Do

Have horses with recurrent muscle problems properly diagnosed with blood tests and muscle biopsy if indicated
Work with an equine nutritionist to formulate appropriate low-starch high-fat diets for susceptible horses
Maintain consistent daily exercise rather than weekend-only workouts for tying-up prone horses
Monitor electrolyte levels and supplement appropriately, particularly selenium in deficient regions
Keep records of tying-up episodes to identify triggers including weather, stress, and diet changes
Learn to recognize early warning signs and slow or stop exercise at first indication
Contact a veterinarian immediately for severe episodes - tying-up is a medical emergency