Update: PSSM in Horses
By Kentucky'>http://www.ker.com/">Kentucky Equine Research Staff · September 29, 2011
The gene that identifies type 2 PSSM one can only be found with a full muscle biopsy. Type 2 PSSM seems to be more prevalent in performance based horses.With the more easily performed test for type 1 PSSM, we have seen the gamut of responses from armchair Veterinarians (generally those with performance bred horses) how relieved they are to find theri horses PSSM free. They would lead you to believe all horses with PSSM are doomed to die,” and in the process would want you to believe their horse is PSSM free, merely because one test came back in their favor.
The more reasonable approach.
“There is more to this test that needs to be considered”.
Many horse enthusiasts have taken the identification of the type 1 PSSM gene and have been able to better understand their horse’s behavior under stress. Unfortunately, some misinformed owners/breeders continue to believe every misstep can be tied to this one type of PSSM. They believe this one test will remove all things bad in the industry.
These people will show you a $35 test and ask that you
join them in their celebration their horse is PSSM FREE!
To date, a muscle biopsy is the ONLY
way to identify type 2 PSSM.
Type 2 PSSM is more prevalent in performance horses.As seen by a plethora of posts in numerous forums by the self-proclaimed “experts”. These armchair Veterinarians seem to be practicing Veterinary Medicine without a license. These “experts” can be found on YouTube diagnosing PSSM to misbehaving horses merely by watching a naughty horse in a video. You will find the same people on Facebook proclaiming the demise of the equine industry to horses with PSSM. They have assigned every bad behavior and injury (from abscess to overwork) to PSSM. These “experts” have not tested their horses for type 2 PSSM or the additional genes that amplify PSSM symptoms.
In this scenario, some knowledge is more
harmful than no knowledge,by leading you to believe a $35 test
gives their horse a clear bill of health.
At the 2011 Texas Equine Veterinary Association (TEVA) conference, one of the leading researchers in equine muscle problems, Stephanie Valberg, D.V.M., Ph.D., of the University of Minnesota College of Veterinary Medicine, brought the audience of veterinarians up to date on polysaccharide storage myopathy (PSSM), one cause of tying-up.Setting The Record StraightAs for as, us, at Smith Show Horses, we feel the industry needs to know all of the facts and you need to know that there are more undiagnosed cases of PSSM than the simple pulling of mane hair cannot detect.Before you book your mare to a stallion represented as PSSM free, and you are worried about symptoms associated with PSSM, ask to see their PSSM results. There are many breeders that will tell you they have the $35 test confirming their horse does NOT have PSSM.A horse with a Negative type 1 PSSM test does not mean the horse is a negative for PSSM.
Through Dr. Valberg explanation, unless, a muscle biopsy has been done on a horse that tests negative for type 1 PSSM, you may be living with a false security.
Omission by ignorance is wrong.
Omission by intention is deceitful.
Before any breeder can proclaim their horse PSSM free… All of the tests need to be completed with negative results.It is much easier to point fingers at one part of an industry and compartmentalize all problems lead to one gene. The last time I saw someone pointing their finger at someone, there were 3 pointing back at them.
I have included excerpts from Dr. Valberg’s discussion that validates what we have felt when the test was first discovered. Our horses were symptom free. Our oldest will be nine in 2012. As more information comes out, we will again regain sanity and realize how much we really don't know. You will find a link to Dr. Valbergs entire discussion at the link at the end of this article.What is Tying-Up?When tying-up happens on a regular basis, it is termed recurrent exertional rhabdomyolysis (RER or chronic tying-up). RER can be caused by several muscle problems. According to Valberg, three genetically identifiable causes of muscle malfunction are 1). Exertional Rhabdomyolysis type 1, 2). PSSM type 1, 3). Malignant hyperthermia. Dr. Valberg, also, warned that there might be other unrecognized causes of RER.PSSM…“While some horses sporadically develop exertional muscle damage as a result of nutritional, training, or environmental factors, others develop RER in spite of a sound diet and environment,” noted Valberg. “Many of these chronic cases are due to an intrinsic and inherited dysfunction of muscle metabolism or muscle contraction.”