Which three drugs were already approved as Veterinary Feed Directive drugs, and therefore were the only ones affected at the time of the VFD final rule in October 2015 (updated VFD process)?

• A. Avilamycin; Florfenicol; Tilmicosin
• B. Penicillin; Tylosin; Oxytetracycline
• C. Neomycin; Streptomycin; Erythromycin
• D. Chlortetracycline; Sulfamethazine; Vancomycin

Answer: (A)

Focus here is understanding which antibiotic products in animal feed were already designated as Veterinary Feed Directive drugs, so they were subject to the VFD process when the rule was updated in 2015.

By October 2015, only three drugs had VFD approval status, meaning their use in feed had to be overseen by a veterinarian through a VFD order. Those are avilamycin, florfenicol, and tilmicosin. Because they already carried VFD drug status, they were the only ones affected by the updated VFD process at that time. Other antibiotics used in feed did not yet have VFD approval and were governed by other labeling or oversight mechanisms, not by the VFD requirement.

In short, the VFD rule targeted drugs with pre-approved VFD status, and those three—avilamycin, florfenicol, and tilmicosin—were the ones meeting that criterion when the October 2015 final rule was issued.