Before antibiotic use became such a hot topic, NPPC had already taken the position of encouraging producer to phase out the use of medically important antibiotics for growth promotion, Dr. Prestage said.

"You are probably aware of FDA Guidance 209 and 213 - that's what they say - a lot of companies made statements saying they are going to eliminate antibiotics from our supply system, whether it's retailers, food companies or whatever," Dr. Prestage said. "Well, I got news for you - that will be the law at the end of 2016. So they can make those statements that if they want to, but the reality is they are saying that we are going to comply with the law."

Dr. Prestage spoke to the media at the World Pork Expo in Des Moines, Iowa.

On Tuesday, the US Food and Drug Administration announced the Veterinary Feed Directive (VFD) final rule, which is designed to promote the judicious use of antimicrobials in food-producing animals.

The new rule brings the use of VFD drugs (animal drugs intended for use in or on animal feed that require the supervision of a licensed veterinarian) under veterinary supervision so that they are used only when necessary for assuring animal health. The VFD final rule provides veterinarians in all states the ability to authorize the use of medically important antimicrobials in feed when needed for specific animal health purposes.

To read more about the VFD final rule, click here.