Practical examples can sometimes be the best way to understand complex rules like those contained in the Food and Drug Administration's Veterinary Feed Directive (VFD).

These questions and answers from recent webinars hosted by Zoetis and Drovers CattleNetwork, and by National Cattlemen's Beef Association might help you apply the new rules to your own operations.

Q: If I want to feed a milk replacer with neomycin and oxytetracycline, will I need a VFD?

A. The answer is yes, because these are both on the list of medically important drugs, says Mike Apley, DVM, Kansas State University.

In fact, it's likely that medicated milk replacers with low levels of antimicrobials intended to be fed continuously will disappear altogether, adds Gatz Riddell, DVM, executive vice president of the American Association of Bovine Practitioners.

Q: Can I feed chlortetracycline in the feed to treat an outbreak of foot rot with a VFD?

A. This clearly will not be allowed, Apley says, since it would be an extralabel use. All extralabel use is banned under the new guidelines.

Q: Can I get a VFD to provide a mineral or feed with chlortetracycline for anaplasmosis prevention?

A. Yes, Apley says, this is a labeled use and in endemic areas would certainly be considered a viable option.

Chlortetracycline is the only antimicrobial approved to be fed for anaplasmosis prevention and it appears that will remain the case after the new rules become effective in 2017, says Roger Saltman, DVM, Zoetis group director for cattle and equine technical services.

Q: Can my veterinarian at my home operation provide a VFD for my operation in another state?

A. No. The VFD for an operation needs to be written by a veterinarian practicing in the state where the animals are being treated, says Paul Ruen, a Minnesota veterinarian who also serves on the AVMA Steering Committee for FDA Policy on Veterinary Oversight of Antimicrobials.

Q: Can I get a VFD to feed Tylosin to reduce liver abscesses?

A. Yes, this is a labeled use for Tylosin and would continue to be a viable use under the new regulations, Apley says.

Q: Do I need a VFD to use monensin (Rumensin) as the only antibiotic in my ration?

A. No, Apley says, this is not a medically important antibiotic and so does not require a VFD.

Q: If I feed monensin concurrently with Tylosin, would I need a VFD?

A. The VFD for Tylosin would need to authorize concurrent feeding of monenesin, Apley says. If a combination feed contains one or more VFD drugs, the combination product requires a VFD, adds Lewis.

Q: Will I need a VFD to use chlortetracycline or oxytetracycline in the feed for treatment of bovine respiratory disease?

A. Yes, you will, because either compound is labeled for such use but both fall into the category of being medically important for humans, Apley says. In fact, he adds, it's best to remember your veterinarian will only be able to authorize uses of fed antimicrobial products which conform to the label. No extra-label use is allowed under the guidelines.

However, your veterinarian may still prescribe extralabel use of an injectable or water-delivered medication. These are regulated by the Animal Decicinal Drug Use Clarification Act (AMDUCA), which is a different set of regulations. To reiterate, an antimicrobial delivered in the water is regulated differently and requires a prescription from your veterinarian, not a VFD.

Q: Will I need a new VFD for each pen of cattle in a feedlot or backgrounding operation each time I pick up a medicated mineral?

A. Not necessarily, but it depends, Apley says. Your veterinarian will outline several things on the VFD that may allow you to treat more than one set of cattle. The FDA has written this into the proposed rules to allow such latitude, adds Lewis.

Lewis says that FDA specifically revised the VFD requirement concerning the number of animals to be treated to aid veterinarians and producers dealing with large numbers of animals and sometimes at multiple locations. Specifically, the VFD will refer to an approximate number of animals. Also, whereas FDA formerly said veterinarians must specify the amount of feed to be fed, the agency has now changed this to include duration of the medication and level of the antimicrobial in the feed, Lewis adds.

More than one of the speakers also noted you must not confuse the expiration date of the VFD with the "duration of use" for drug or combination you are feeding. The veterinarian sets the expiration date and it cannot exceed six months. The duration of use is the length of time the drug may be fed to the animals. It can be shorter or longer than the VFD and is established on the drug label. Producers must pay attention to this, Lewis says.

Q: Is a VFD specific for only a name-brand of a drug, or can it include generic substitutions?

A. At the veterinarian's discretion, a generic can often be substituted for a name-brand product, says John Hallberg, DVM, director of U.S. regulatory affairs for Zoetis. However, there are "pioneer" products sometimes have combination labels that generic drugs do not. This means is your veterinarian is prescribing a combination product and the generic is not approved, then it cannot happen because this would be an extralabel use, and therefore illegal.

Q: If I have leftover products with old labels after the regulatory effective date of Jan. 1, 2017, can I continue using them without a VFD?

A. No. You must have a VFD in place to use all affected products after the new rules go into effect, says Hallberg. However, products with old labels do not have to be destroyed. They can be used under a new VFD.

Q: If a veterinarian owns and operates a cattle operation where he/she needs a VFD to feed antibiotics, can that person write his own VFD?

A. This is a viable option, says Lewis. The VFD requires three people to be named: The veterinarian, the distributor and the producer. The veterinarian legally could be two or even three of these individuals.

VFD request just a starting point

A request for a Veterinary Feed Directive is not an automatic authorization, says Mike Apley, DVM, Kansas State University, but instead it initiates a conversation with your veterinarian.

Then your vet will consider several things:

  • Are there non-antibiotic alternatives?
  • Does the proposed use match the product label specifications?
  • Do you have a genuine need?
  • What is the efficacy of the proposed antibiotic to be fed in relation to your animals' disease challenge?
  • Can you meet the withdrawal time prior to slaughter?
  • Are there issues with antimicrobial resistance?

Cattle drugs currently requiring a VFD

  • Tilmicosin

Cattle drugs which change from over-the-counter sales to use only by veterinary feed directive in 2017:

  • Neomycin
  • Tylosin
  • Virginiamycin
  • Chlortetracycline
  • Oxytetracycline