The FDA this week confirms the effective date of December 1, 2016, for its direct final rule aimed at protecting therapeutic uses of medicated feeds for minor food-animal species. The new rule helps to address some concerns over the implementation of the FDA’s Guidance for Industry 213, which removes “production” claims such as improved growth or feed efficiency from medically important antibiotics used in feeds.

Based on the existing drug category definitions, FDA reports, the voluntary withdrawal of production indications by drug sponsors would, in some cases, result in a change to a medicated feed drug's category, potentially leading to additional consequences not foreseen at the time the program was initiated. Specifically, the rule addresses concerns that current categorization of drugs used in medicated feeds could threaten therapeutic uses of those drugs in minor food-animal species. Some of the medically important antimicrobials affected by GFI 213 are approved for production use in feed for major species of food animals such as poultry, swine and cattle, and also for therapeutic use in feed for minor species such as sheep, goats, catfish, game birds, honey bees and others.

In the new rule, FDA amends 21 CFR 558.3 Definitions and general considerations applicable to this part (§ 558.3) to base the definition for each of the two categories (Category I and Category II) of new animal drugs used in medicated feeds only on approved uses in major species. 

In general, FDA says, animal drugs approved for use in animal feed are categorized based on whether or not there is a withdrawal period when animals are given the lowest dose or feeding level of the drug in order to avoid unsafe drug residues in edible products derived from the treated animal. Category I animal drugs do not have a withdrawal period requirement for the lowest dose in each species for which they are approved. For Category I drugs, the Type A medicated article, the most concentrated form of the drug used by feed mills, can be used by both FDA-licensed feed mills and unlicensed feed mills to produce the medicated feed.

Category II includes animal drugs that have a withdrawal period at the lowest dose level for at least one species for which the drug is approved. Currently, only licensed feed mills may produce medicated feed using Category II Type A medicated articles. In the U.S., there are far more unlicensed feed mills than licensed ones.

Animal drugs for minor species remain subject to the requirements of their FDA-approved label, including withdrawal periods, despite any changes in categorization, according to the FDA. This direct final rule will preserve the availability of medicated feed drugs intended for therapeutic use in minor animal species by ensuring that these products can still be produced by both licensed and unlicensed feed mills.

The FDA seeks public comment on this direct final rule for 75 days following publication in the Federal Register. If no significant adverse comments are received, the rule will take effect 135 days following publication. For additional information, please see the Federal Register Notice.

To electronically submit comments to the docket, visit and type FDA-2016-N-1896 in the search box.