Many inorganic mineral elements are essential nutrients. These are generally classified according to the amount required into macro minerals and trace elements. Three of the macro- mineral elements also act as electrolytes.
Dietary requirement standards have been developed for all the above with the possible exception of Chromium which remains less well understood. Not only the absolute requirements for different classes of horse, but some desirable standards for the ratio between certain minerals have been determined e.g. Calcium: Phosphorous ratio of 1.8 – 2.2: 1.0 and Zinc: Copper ratio of 3: 1 to 5: 1
Bio – availability of minerals is quite variable and often the digestibility of inorganic mineral compounds is low. For this reason, some minerals and trace elements are combined with amino acids to enhance absorbtion from the gut. These so called chelated minerals show improved absorbtion and effectiveness in the body, but commercially this is offset by them being more costly.