Antibiotic use in livestock agriculture is among the hottest topics in U.S. beef production. The conventional wisdom is that the use of antibiotics and antimicrobials in food animals can spur the development of resistance genes in humans, making it more difficult to fight illnesses.

However, several layers of science-driven protection have been put in place to ensure antibiotics are used to keep animals healthy without harm to public health. The U.S. Food and Drug Administration (FDA) and USDA's Food Safety & Inspection Service (FSIS) oversee protocol to ensure beef products entering the food supply don't contain violative antibiotic levels.

FDA approves drug labels with specific disease indications, animal classes, routes of administration, durations of therapy, and doses. FSIS conducts tests to ensure beef products entering the food supply don't contain violative antibiotic levels.

Beef Quality Assurance (BQA) programs support the role that FDA and FSIS play in making science-based decisions regarding the safety and efficacy of antibiotics and antimicrobials used in animal agriculture. BQA programs also stress that, starting at the cow-calf level, all cattle producers have an ethical responsibility to use antibiotics in such a manner that the animals they raise do not carry violative residues.

BQA's “Producer Guidelines for Judicious Use of Antimicrobials,” which have been in place since 1987, specifically outline the appropriate use of antibiotics:

  • Avoid using antibiotics that are important in human medicine.

  • Use a narrow spectrum of antimicrobials whenever possible.

  • Treat the fewest number of animals possible.

  • Antibiotic use should be limited to prevent or control disease and not used if the principal intent is to improve performance.

A veterinary client patient relationship (VCPR) is the first step in ensuring appropriate use of all cattle-health products. Federal law enables licensed veterinarians to adjust the use of an FDA-approved drug other than as labeled when the health and well-being of that animal or group of animals are threatened.

The FDA considers a valid VCPR to exist when:

  • The veterinarian has assumed clinical responsibility for the animals.

  • The owner of the animals has agreed to follow the veterinarian's instructions.

  • The veterinarian has sufficient direct knowledge of the animals' condition and their care.

  • The veterinarian is available for follow-up evaluation.

One aspect of a VCPR that often arises is extra label drug use (ELDU).

Conditions that must be met before ELDU may be legally considered are:

  • A careful diagnosis is made by an attending veterinarian.

  • There is no marketable drug specifically labeled to treat the condition diagnosed, or treatment at the dosage recommended by the labeling was found clinically ineffective.

  • Assurance that identity of the treated animal(s) is carefully maintained.

  • A significantly extended drug withdrawal is assigned to the animal(s) so that no violative residue occurs.

  • If the individual animal cannot be identified for the extended withdrawal time, then the extended withdrawal time must be applied to the entire group.

But, even if the rationale for ELDU is reasonable, ELDU must not lead to a violative drug residue.

An example of ELDU of injectable drugs that can cause violative residues is the use of penicillin G at a higher-than-labeled dose. Available over the counter, the label dose of penicillin G is 1cc/100 lbs. of body weight — at no more than 10 cc/injection site.

Only a veterinarian can make the decision that the medically appropriate dose is more than the dose label; and the veterinarian must add a prescription label to the drug. When this altered dose is used, the necessary slaughter withdrawal time must be changed from the withdrawal time on the label by the prescribing veterinarian.

If there isn't sufficient information to establish this slaughter-withdrawal time, the animal may not enter the food chain.

There is no ELDU for feed additives. Not even a veterinarian may legally prescribe or use drugs in feed in an extra-label manner. Also, feeding rations containing unapproved combinations of drugs — including unapproved combinations of antibiotics and ionophores — is illegal.

Next Page: ELDU record-keeping requirements

This means that the concurrent feeding of drugs not approved to be fed to cattle together violates federal regulations. One such scenario relates to “AM/PM” feeding of rations containing feed additives (feeding one drug in the ration in the morning and feeding a different drug in the afternoon) not approved by the FDA to be fed in combination with each other.

Unapproved combinations of these ionophores and feed antibiotics are prohibited. Label directions on feed additives must be followed exactly, and producers are required by law to make all feed additive use records available to an FDA inspector upon request. A good management practice is to include the exact times rations containing a feed additive were removed and the exact time a ration containing a different feed additive was delivered to the cattle.

Remember, the laws and rules are different for injectable drugs and drugs administered in the feed.

Clint Peck is director, Beef Quality Assurance, Montana State University.

Guidelines

ELDU record-keeping requirements*

  • Animals identified, either as individuals or a group.

  • Species treated.

  • Number of animals treated.

  • Conditions being treated.

  • The established name of the drug and active ingredient.

  • Dosage prescribed or used.

  • Treatment duration.

  • Specified withdrawal, withholding or discard time(s), if applicable, for meat, milk, eggs, or animal-derived food.

  • Keep records for two years.

  • FDA may have access to these records.

*BQA guidelines recommend keeping these records for all livestock treatments.

Resources

For more info

For detailed information on prudent use of antibiotics in animal agriculture, go to www.sdbqa.com to download “Using FDA Approved Medications: Common Scenarios.” Authors are: Mike Apley, DVM, Kansas State University; Virginia Fajt, DVM, Texas A&M University; and Dee Griffin, DVM, University of Nebraska-Lincoln Great Plains Veterinary Educational Center.