• Sulfur is necessary for the life of animals, for it is an essential part of most proteins. Sulfur is necessary for the synthesis of sulfur bearing amino acids.
• A deficiency limits non-protein nitrogen utilization.
• Sulfur is a component of methionine and cystine (sulfur amino acids), a component of biotin and thiamine, and is involved in tissue respiration and energy metabolism through the sulfhydryl chemical groups. The optimum amount of Sulfur is in a range of 0.20 - 0.22% of the total dry matter. Sulfur is acid in nature. Sulfer-nitrogen ration should be 1-10.
• Sulfur supplementation may be necessary for ruminants when urea is being fed as a source of non-protein nitrogen.
• Sulfate - S limits Cu and Ca storage and protects against the toxicity.
• High Zn increases fecal S.
• SO4 decreases liver Mo.

Effects of an Excess of Sulfur:

• Creates an acid rumen.
• Increases need for copper.
• A laxative effect - black scours.
• Sulfur toxicity is unlikely under normal conditions.

Effects of a Deficiency of Sulfur:

• Limits NPN (non protein nitrogen) utilization. 
• Reduced growth rate due to sulfur amino acid requirements for protein synthesis not being met for the animal.
• Poor hair coat - shedding wool in sheep.
• Poor hair, hoof, and horn development.
• Excess saliva.
• Watery eyes.