Resources and insights

Jax is n/P1, n/P2, n/Px. I got him when he was an unbroke 4 year old, and he was quirky that first year but then had over 2 great years of riding. He didn’t go highly symptomatic until he was 8 years old, but right as he turned 8 he crashed hard. Early symptoms included shaky on trailer rides, sticky stifles when out of work, and on/off lameness. As he became more symptomatic he began urinating small amounts of dark brown at the end of the stream – he did this for about a year before major symptoms, right around the time he became overly spooky and started bolting under saddle. These symptoms progressed to shakiness verging on spasms during trailer rides (has gone into full-blown tie up on longer trailer rides), sticky stifles at all times to the point he could barely trot, lumbar and skin pain that would cause him to drop from pressure, couldn’t hold up legs for farrier, and more drastic behavioral changes (aggression towards pasture mates, rearing during handwalks, crow hopping under saddle – but no full-on bucking, etc.). He started twisting his hind legs when walking, had a strange hitching gait in the back…

This was written in response to a post on the PSSM Forum on Facebook. Negative nitrogen balance is a normal process that is helpful under the right circumstances. It is not confined to PSSM horses. You have certainly experienced it yourself. There are some circumstances under which you cannot consume enough dietary protein to meet your needs for amino acids. When you have the flu, for example, your immune system is working hard and you need a lot of amino acids to synthesize proteins. Your body tears down muscle in order break protein down into amino acids for use elsewhere. Some of the amino acids are burned for energy. All amino acids have a chemical structure with a central carbon atom bonded to four different parts: an amino group, a carboxyl group, a hydrogen atom, and an “R” group that is a different group for each amino acid. When an amino acid is burned for energy, one of the first steps is the removal of the amino group. If this is not used to synthesize one of the nonessential amino acids, it is discarded as waste. To do that, it enters a metabolic cycle called the urea cycle and is…