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PSSM2 - hereditary muscle diseases in horses of almost all breeds

PSSM2 (Equine Myopathy) is a multifactorial muscle disease in horses in which the occurrence of symptoms is influenced by a hereditary predisposition and various environmental factors (age, exercise, feeding). Typical symptoms include reluctance to move, stiffness, periodic lameness, and even possible exercise intolerance in daily practice. Almost any breed of horse can be affected.


Your horse ...

  • is frequently reluctant to move forward?
  • often has very tense muscles?
  • suffers from shifting lameness?

Typical Example

Raised with care and trained with patience, a great young horse develops into a promising sports partner. Around 7 years of age, however, the picture suddenly changes. The previously willing and motivated horse often seems listless or lacking forward movement and power. His behaviour changes, becoming increasingly uncooperative and unwilling to be saddled or stand still with the farrier. Veterinarians and trainers are consulted. Does the feed or training need to be adjusted? Is there a lack of consistency?  No method shows lasting success. The horse is increasingly tense-muscled and stiff.  Veterinary investigations cannot find any reason for the recurrent, shifting lameness, and training must be paused again and again. No therapy seems to improve the horse’s condition for more than a few days.


This is a typical example of a horse with PSSM2 Equine Myopathy, a hereditary muscle disease that occurs in almost all breeds of horses.  But what does PSSM2 actually mean?  What symptoms do affected horses exhibit, and how can these horses be helped?


Research into this complex muscle disease is exciting and ongoing.