P5 - Genetic Testing is Available
The PSSM2 Variant labelled P5/P6 is a recessive gene meaning the horse must inherit one copy from each parent in order for it to be displayed
P5 and P6 have been found in Thoroughbreds, Appaloosas, Quarter Horses and Paints. P5 specifically in heavier breeds such as Shire and Clydesdale
Horses carrying the P5 or P6 variant develop symptoms of exercise intolerance as they age. The age of onset and the severity of symptoms is variable.
Supplementing the diet with complete protein (whey), complementary protein (soy) or with specific amino acids that are typically limiting in plant protein (lysine, methionine, and threonine) is the management strategy for a horse testing positive at this time. Not all horses respond to management.