The ABCs of Medicated Feeds
March 10, 2017

The initiation of the Veterinary Feed Directive in January changed the way feed-grade antibiotics are acquired. The cattle industry published an article to help simplify medicated feeds.

Medicated feeds are categorized as Type A, B or C.
  • Type A medicated articles are products of standardized potency, intended for use in the manufacture of other medicated articles or medicated feeds. Aureomycin® 90 (Zoetis) and Tylan® 100 (Elanco) are examples of this classification. They are what we commonly refer to as a "raw drug," purchased from the pharmaceutical company for use in feed mills.
  • The second category is Type B medicated feed, which is produced using a Type A medication and is intended solely for further blending before being fed. The most common Type B feeds are medicated supplements such as loose meals, pellets and crumbles that are used as ration ingredients and are not fed free-choice.
  • Lastly, there are the Type C feeds. These include complete feeds and minerals or grain mixes fed as a top dress or offered free-choice to supplement the daily ration. Veterinary Feed Directives are written for Type C feeds, with the medication specified as grams per ton in a 90 percent dry matter ration.
Consider the steps from Type A to C as a simple matter of diluting the concentration to a level suitable for consumption: raw drug to supplement to complete ration. They are all viewed as medicated feeds by the U.S. Food and Drug Administration, with only Type C being legally approved for free-choice feeding.

Minerals medicated with antibiotics may fall under the classification of either Type B or C. The status of a given mineral is important to know in order for veterinarians to write a valid VFD and for producers to feed the mineral properly. Most minerals containing the antibiotic chlortetracycline (CTC) are Type B medicated feeds and are tagged to be fed as part of a total mixed ration, with directions to feed daily. These supplements are meant to be included in a TMR after obtaining a VFD but are not offered free-choice; to do so would be an off-label use and would be in violation of the legal feeding application.

Reprinted in part from Drovers