Excessively nervous behaviour is attributable to a lack of magnesium. Many animals have become much easier to manage when dolomite has been added to their rations, changing from excitable to quite calm individuals.
Conditions caused by a deficiency of magnesium (with calcium) include, grass, lactation and travel tentancies, mastitis, arthritis, stringhalt, founder, warts (the virus that causes these prefers a magnesium deficient host), and uneven bone growth, as well as most of the conditions related to calcium deficiency.
Calcium is requried for the nervous and muscular systems, normal heart function and blood coagulation. It is also needed for bone growth. However Calcium must always be considered in conjunction with magnesium.
Calcium is needed for Bone growth, repair and strength, muscle contraction, blood clotting and metabolism.