The requirement for sodium and chlorine is commonly expressed as the salt requirement. Sodium is the major mineral in fluids outside the body cells. Chlorine occurs both inside and outside the cell. They both function to maintain the volume, pH and osmolarity of body fluids. Sodium is involved in muscle and nerve function.
Chlorine is essential for certain digestive enzymes and for carbon dioxide transport.
The specific requirements for sodium and chlorine are unknown. Including 0.25 percent salt in the ration dry matter of full-fed beef cattle appears to be adequate to meet the requirement for sodium and chlorine. Recent research indicates less may be sufficient. Salt is often fed free-choice. Consumption varies, but cattle usually exceed their requirements when given free access to salt.