March 2015
Farm & Field

Animal Antibiotics

A proposed phase-out of certain antibiotic use by the FDA could affect how farmers treat their cattle.


The Food and Drug Administration is implementing a voluntary program within the animal, feed and drug industries to phase out the use of certain antibiotics in the use of animal feed or drinking water. To date, all animal pharmaceutical companies have agreed to fully comply. Here’s what you need to know about the changes:

Antimicrobial resistance

Resistance is an important public health issue not only in this country but globally. Microbes have an incredible ability to mutate and adapt to their environment. In the presence of less-than-killing-doses of antimicrobials, resistance can and does develop. What that means is that the drugs we have today can eventually quit working if we don’t address this issue.

Changes to FDA Rules

In an effort to curtail antimicrobial resistance crossover from food animals to humans, the FDA is modifying how feed- and water-based antimicrobials are used in animal agriculture. FDA has identified medically important antimicrobial drugs used for both humans and animals and will restrict usage of these (see Table 1 for a complete list) from current practices. Luckily, the drugs most used in humans are least used in livestock and vice versa (see Figure 1 on right).


In a nutshell, the only thing that will go away completely is the use of these shared drugs in low doses for the enhancement of growth or feed efficiency. These shared drugs will still be available for treatment, control and prevention of disease in livestock. However, they will no longer be available over-the-counter and will require a veterinary feed directive – essentially a prescription for livestock. This means your livestock will require veterinary oversight prior to the purchase of feeds, supplements and/or additives containing the targeted drugs. You or your veterinarian will provide your feed dealer with a VFD and both will be required to keep these on file for a specified period of time. There are specific rules that govern what is a valid veterinary-patient relationship, and the specific details are still being worked out.

An important detail to keep in mind is that use of animal-only drugs will not change. Animal-only drugs you are able to purchase OTC today you will be able to continue to purchase OTC after these changes are implemented.

As of the writing of this piece, implementation is said to start "within 3 years" of the writing of the last FDA document. That places the start roughly in December 2016. However, details are still being worked out with all of the participating stakeholders.



So what can you do in the meantime? While all legal uses and combinations of drugs are still available OTC today, including drug claims for growth enhancement and improved feed efficiency, you might want to start preparing yourself prior to 2016.

Producers can start looking into other options (perhaps switching from a shared-use drug to an animal-only use drug) and also start discussions with their veterinarian and feed distributor on the coming changes.

Feed Dealers can start discussions with their customers, local veterinarians and vendors to foster a line of communication on making these changes.

In summary, the proposed FDA voluntary program to restrict use of selected medically important drugs in animal feed and water is designed to help protect public health and keep both humans and animals safe and healthy. To learn more about these proposed regulations visit FDA’s website at

Jackie Nix is an animal nutritionist with Ridley Block Operations ( You can contact her at This email address is being protected from spambots. You need JavaScript enabled to view it. or 1-800-325-1486 for questions or to learn more about SWEETLIX mineral and protein supplements for cattle, goats, horses, sheep and wildlife. References available upon request.