In January 2017, FDA and animal drug manufacturers completed the voluntary transition of antimicrobial drugs of medical importance used in animal feed to Veterinary Feed Directive (VFD) marketing status under Guidance for Industry (GFI) #213.
Since that time, the FDA has received questions from stakeholders relating to certain uses of free-choice medicated feeds (products that contain one or more animal drugs and are placed in feeding or grazing areas for animals to freely consume) for the control of active infection of anaplasmosis in cattle. Some of these questions involved use of such feeds that are not in compliance with currently approved use conditions.
We acknowledge that anaplasmosis is an important animal health concern for the cattle industry and that practical control measures are needed, particularly during the time of year in which insects associated with spreading disease are most active. While the FDA understands that free-choice medicated feeds can be an important tool for controlling this disease, the agency needs to ensure that the feeds are used in compliance with the approved conditions of use.
The FDA is reminding veterinarians, animal producers, and feed manufacturers that when medicating animals through free-choice mineral supplements, the only legal options are approved free-choice medicated feed formulations. While the agency continues to consider ways to address these concerns, it is providing Question and Answers: FDA Approved Free-Choice Feeding Options for Anaplasmosis Control in Cattle to clarify the issues and assist with the appropriate selection and use of approved VFD free-choice medicated feed products for the control of active infection of anaplasmosis in cattle.
The FDA expects that any use of free-choice medicated feeds for controlling anaplasmosis in cattle would be limited to situations when active anaplasmosis is a significant concern, such use is consistent with the approved dose, and these feeds are used under veterinarian oversight.
Questions not addressed in the Q&A document may be directed to AskCVM@fda.hhs.gov.

Source: FDA