Aschenbach JR¹, Becker SK¹, Sponder G¹, Kolisek M²

¹ Freie Universität Berlin, Berlin
² Comenius University, Martin, SK
 

Magnesium (Mg) is one of the most relevant ions in the body of mammals. It is regulated via absorption from the gastrointestinal tract and urinary excretion. Both processes are devoid of hormonal control; they are merely driven by concentration gradients. Cows consume relatively higher amounts of Mg than omnivorous species like man because vegan fibre-rich diet is usually rich in Mg. Accordingly, Mg deficiency in herbivores is more often of secondary than primary nature. In ruminants, potassium-rich sodium-deficient diets with high protein content, especially spring grass, are known to interfere with Mg absorption to cause a secondary Mg deficiency (i.e., grass tetany). A Mg deficiency further promotes other diseases. Most evidently, Mg deficiency decreases the effects of parahyroid hormone, facilitating hypocalcaemia around parturition that may progress to paresis (i.e., milk fever). Finally, there is emerging evidence that postparturient metabolic syndrome in dairy cows is enforced by Mg deficiency or, alternatively, alleviated by excess provision of Mg with the diet. Mechanistic studies suggest stabilization of glucose and lipid metabolism as the underlying principle.