Too little Sulfur (S)
Sulfur is a chemical element. In the body, sulfur is part of the amino acids cysteine and methionine. These amino acids are referred to as sulfur-containing amino acids, and they are represented in practically all proteins that makes up the body. Sulfur is among others also part of the B-vitamins thiamine (vitamin B1) and biotin, the natural anticoagulant heparin, and chondroitin sulfate, an important constituent of cartilage in all joint surfaces.
Horses cover their requirements for sulfur through intake of organic, sulfur-containing feed molecules, mainly the amino acids methionine and cysteine.
When the ration has sufficient amounts of protein, preferably from several sources, sulfur deficiency will not occur.