care must be taken to mix micronutrients and feed additives uniformly in the ration micronutrien are feed ingredients such as minerals and vitamins which are used in small amounts in the ration a feed additive is a nonnutritive substance that is added to feed to promote more rapid growth to increase feed efficiency or to maintain pr improve health. feed additives fall into two major groups-growth regulators(mostly hormones) and antibiotics. micronutrients and feed additives are used in very small amounts some are harmful if fed in too large a quantity the animal might receive too much of these additives if they are not carefully mixed into the ration it is essential to feed only the amount recommended and mix it well with the rest of the feed ingredients