Welfare management of equine muscle disorders including tying up (rhabdomyolysis), PSSM, and MFM, covering diagnostic approaches, exercise management, and the welfare of horses with chronic conditions.
Key Facts
Equine rhabdomyolysis (tying up) causes severe muscle pain, stiffness, and myoglobinuria that significantly compromises welfare
Polysaccharide storage myopathy (PSSM) is a genetic condition causing recurrent muscle dysfunction in quarter horses and warmbloods
Myofibrillar myopathy (MFM) is a recently characterized condition causing exercise intolerance in sport horses
Genetic testing can identify horses with PSSM type 1, enabling dietary management to prevent episodes
Horses experiencing acute tying up show clear pain indicators including sweating, trembling, and reluctance to move
Dietary management reducing starch and increasing fat is highly effective at preventing PSSM episodes
Chronic unmanaged muscle disorders cause ongoing welfare compromise through exercise intolerance and pain
Welfare Considerations
Equine muscle disorders cause welfare suffering that spans acute crisis episodes and chronic daily compromise. The acute tying up event is a welfare emergency — horses in severe episodes experience intense pain from muscle ischemia and breakdown, requiring immediate veterinary intervention for pain management and fluid therapy. The chronic management challenge is equally important: horses with PSSM or MFM who are managed without appropriate dietary modification and exercise programming experience repeated episodes and persistent muscle discomfort. Genetic testing for PSSM type 1 provides an opportunity for welfare-protective management before clinical episodes begin — identifying at-risk horses enables dietary intervention that can prevent suffering entirely. Investment in correct diagnosis and management pays welfare dividends across the horse's lifetime.
What You Can Do
Genetic test breeding stock and young horses in predisposed breeds for PSSM type 1 before clinical problems develop
Learn to recognize early signs of tying up and have a veterinary response plan for acute episodes
Work with a veterinary internist or sports medicine specialist for diagnosis and management of recurrent muscle problems
Implement dietary management for PSSM-positive horses — reducing starch and adding fat sources prevents most episodes
Maintain consistent exercise programming rather than irregular intense work, which triggers episodes in susceptible horses
Monitor urine color after exercise as an early indicator of myoglobinuria signaling a tying up episode