17/04/2026
🐴 Understanding PSSM1 in Horses
Not all performance issues are training-related… sometimes, it’s genetic. 🧬
Polysaccharide Storage Myopathy Type 1 (PSSM1) is a hereditary muscle disorder that affects how horses store and use energy. This leads to abnormal glycogen build-up in the muscles, which can cause discomfort and reduced performance.
Common symptoms include:
🐎 Muscle stiffness (especially after rest)
🐎 Reluctance to move or poor performance
🐎 Tying-up episodes (painful muscle cramping)
🐎 Sweating and trembling during exercise
Commonly affected breeds:
🐴 Quarter Horse
🐴 Paint Horse
🐴 Appaloosa
🐴 Draft Horse (e.g., Percheron, Belgian Draft)
Because PSSM1 is inherited in a dominant manner, even one copy of the mutation can affect a horse.
✨ The good news? With genetic testing, you can:
✔ Identify affected horses early
✔ Adjust diet and exercise for better management
✔ Make informed breeding decisions
Knowledge is power when it comes to your horse’s health.