Animal nutrition and acid-base balance.

In domestic animals, acid-base balance may be influenced by nutrition. The major research effort in this area has been made on the prevention of hypocalcemic postparturient paresis in dairy cows. This disorder is caused by the sudden increase of calcium secretion into the colostrum. The manipulation of the dietary cation-anion difference makes it possible to maintain the cows in metabolic acidosis during the critical period that precedes calving, presumably via a mechanism that involves the strong ion difference in the extracellular fluid. As a consequence the mobilization of calcium is enhanced and the incidence of the disorder is decreased. Conversely, a dietary induced metabolic alkalosis leads to a more severe degree of hypocalcemia and the incidence of the disease is increased. The underlying mechanisms of the prevention are only partially understood. Nevertheless, this preventive method is already widely applied in practice. Nutrition effects on acid-base balance also influence growth and food intake in higher vertebrates and fish. As a consequence, the incidence of developmental orthopedic diseases in fast-growing domestic animal species may be affected. Also, the bone mineral content of athletic horses may be influenced by dietary induced modification of the acid-base status. The mineral loss due to metabolic acidosis may lead to an increase in the incidence of stress fractures. This overview should give insight into relevant aspects of nutrition and acid-base balance in domestic animal species.