Feed additives are not nutrients nor are they required in the diets of animals. They often, however, result in improved animal growth rates, feed conversions, and are generally profitable when fed correctly. Some feed additives are regulated by the U.S. Food and Drug Administration (FDA), and it is crucial that regulations regarding their use and inclusion level be closely followed. The regulations are published annually in the Feed Additive Compendium. Appropriate usage and withdrawal (if necessary) information for each additive can be obtained from the manufacturer and/or from the feed tag affixed to commercial feeds.
There are various groupings of feed additives, which include: