Sodium Nutrition of Livestock and Poultry
by Larry L. Berger, Ph.D.
Professor, Animal Sciences
University of Illinois
Animal nutritionists have recognized sodium as an essential nutrient for hundreds of years. Sodium is unique in that animals have a greater appetite for salt than the other nutrients.
Even though the body only contains about 0.2% sodium, it is essential for life and is highly regulated. About half of the sodium in the body is in the soft tissues, and half in bone. Sodium makes up 93% of the basic mineral elements in the blood serum and is the chief cation regulating blood pH. Muscle contraction is dependent on proper sodium concentrations. Sodium plays an essential role in nerve impulse transmission and the rhythmic maintenance of heart action. Efficient absorption of amino acids and monosaccharides from the small intestine also requires adequate sodium.
Producers of confined livestock and poultry often consider lowering the salt concentration in animal diets to reduce sodium and chloride levels in manure to maximize manure application rates. Owners of grazing livestock, trying to reduce costs, sometimes question the need for salt supplementation. The purpose of this article is to review recent research demonstrating the essentiality of sodium supplementation for optimal performance. In addition, new information on disease or management problems associated with suboptimal sodium nutrition will be discussed.
In a recent review, Chiy and Phillips (1995) identified four conditions where sodium deficiency is most likely: 1) Lactating livestock which have high sodium losses in the milk; 2) Rapidly growing livestock and poultry with high sodium retention; 3) Grazing animals under heat stress conditions where forage sodium concentrations are low and there are large losses in sweat; and 4) Animals grazing fertilized pastures where potassium levels are high and sodium is low.