Prudent Use of Antibiotics in Beef Production
By Clint Peck, Director Beef Quality Assurance, Montana State University
A priority for all cattle producers is the health and well-being of their animals. Antibiotics and antimicrobials are an important and necessary tool in protecting animal health and well-being. However, antibiotic use in livestock agriculture and the potential for antibiotic residues in beef at the consumer level is among the hottest topic areas in U.S. beef production circles. There has been a rising level of scrutiny about the use of antibiotics and antimicrobials in animal agriculture. Media reports and activist rhetoric would lead beef consumers to believe that the use of antibiotics and antimicrobials can spur the development of resistance genes in humans making it more difficult to fight human illnesses. An example: “Factory-farmed cattle eat feed laced with hormones and antibiotics to fast-forward their growth, which in turn breeds superbacteria that are resistant to the antibiotics humans rely on.” – MensHealth.com
Roles and responsibilities
Several layers of protection have been put in place to ensure antibiotics are used to keep animals healthy without harm to public health. The approval and use of antibiotics to treat sick animals and to maintain animal health is a science-driven process.
This process is led by the U.S. Food and Drug Administration (FDA) which approves drug labels with specific disease indications, animal classes, routes of administration, durations of therapy, and doses. The USDA Food Safety & Inspection Service (FSIS) conducts tests to ensure beef products entering the food supply do not contain violative antibiotic levels.
National 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 There has been a rising level of scrutiny about the use of antibiotics and antimicrobials in animal agriculture antimicrobials used in animal agriculture. We emphasize that deviation from label inclusions could potentially cause lack of effectiveness for the disease being treated, toxicity to the animals, or a violative residue in food harvested from the animal. BQA Producer Guidelines for Judicious Use of Antimicrobials, which have been in place since 1987. The guidelines 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 should not be used if the principle intent is to improve performance.
BQA programs stress that starting at the cow-calf level all cattle producers have an ethical responsibility, along with a compelling economic need, to use antibiotics in such a manner that the animals they raise do not carry residues that violate FDA standards.
The veterinary-client relationship
A producer-veterinarian relationship is the first step in making sure that all cattle health products are used appropriately. Formally, this is known as a veterinary client patient relationship” (VCPR).
The FDA considers a valid VCPR to exist when:
The licensed 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 is that often arises is extra label drug use (ELDU). The Animal Medicinal Drug Use Clarification Act (AMDUCA) of 1996 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 is threatened. But, the law is clear that ELDU shall not be considered if the purpose is for growth promotion, reproductive performance, or alteration of cost of therapy.
This seems very straightforward, but there’s one very important point in the law, even if the rationale for ELDU is reasonable – ELDU must not lead to a violative drug residue. Additional 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.
Examples of ELDU
An example of ELDU of injectable drugs that can cause violative residues is using penicillin G at a higher than labeled dose. Available over the counter (non-prescription), and the label dose of penicillin G is one (1) CC per 100 pounds of body weight – at no more than 10 CCs per 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 is not sufficient information to establish this slaughter withdrawal time, then the animal may not enter the food chain. Other examples of ELDU are administering Excede® (ceftiofur crystalline acid) or flunixin meglumine (e.g., Banamine®) by unapproved routes. Excede administered subcutaneously (SQ) in the neck region instead of the label directed middle portion of the back of the ear or base of ear locations changes the disposition of the drug. This increases the potential for a violative residue at the injection site well beyond the label withdrawal time of 13 days. Altering the administration of flunixin meglumine from the approved intravenous (IV) route to SQ or intramuscularly (IM) because of convenience is very likely to result in a violative residue and causes a great deal of tissue damage at the injection site. Violative residues have been documented by the FDA to occur in cattle beyond the four-(4) day withdrawal time the FDA requires for IV use of flunixin meglumine.
ELDU and Feed Additives
Feed additives must be used only according to the label instruction. Not even a veterinarian may legally prescribe or use drugs in feed in an extra-label manner. Also, feeding rations containing non-approved combinations of drugs is illegal. This means that 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.
The FDA rules out AM/PM use of feed additives which are not approved to be fed in combination. These products are explicitly intended to be fed as the sole ration and one feed additive should be discontinued prior to another additive being offered to the animal.
The following combinations of feed additives are examples of those that have been approved by the FDA for concurrent use when fed according to label dosage and use:
Bovatec® (lasalocid) + Aureomycin® (chlortetracycline)
Deccox® (decoquinate) + Aureomycin® (chlortetracycline) Rumensin® (monensin) + Tylan® (tylosin) + Deccox® (decoquinate).
Rumensin® (monensin) + Tylan® (tylosin) + MGA® (melengestrol acetate).
Any other unapproved combinations of these ionophores and feed antibiotics are prohibited. Label directions on feed additives must be followed exactly, including for example disease indication, drug concentration in the feed, frequency and duration of administration, and withdrawal times.
Let’s consider an example to clarify. A group of cattle are on a ration with approved levels of Rumensin® and Tylan®. If these cattle develop a health condition for which the veterinarian recommends feeding a product containing any of the chlortetracycline (CTC) family of products, the ration containing Rumensin®/Tylan® must be stopped prior to beginning the ration containing CTC. This includes top-dressing CTC pellets over a ration containing a medication for which it combination feeding has not been approved. Once the CTC therapy is completed, the feed containing Rumensin®/Tylan® can be offered again.
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. This helps the FDA inspector appreciate the diligence practiced to prevent cross contamination of rations containing feed additives not approved to be fed in combination. It should be clear that the laws and rules are different for injectable drugs and drugs administered in the feed. Questions about the legal use of over the counter and prescription drugs can be addressed by your veterinarian.
Requirements for Extra-Label Drug Use (ELDU)
• ELDU is permitted only by and/or under the supervision of a veterinarian.
• ELDU is allowed only for FDA approved animal and human drugs.
• A valid Veterinarian/Client/Patient Relationship is a prerequisite for all ELDU.
• ELDU for therapeutic purposes only (animal’s health is suffering or threatened) - not drugs for production use.
• Rules apply to dosage form drugs and drugs administered in water. ELDU in feed is prohibited.
• ELDU is not permitted if it results in violative food residue, or any residue which may present a risk to public health.
• FDA prohibition of a specific ELDU precludes such use.
ELDU Record Keeping Requirements*
• Identify the animals, either as individuals or a group.
• Animal species treated.
• Numbers of animals treated.
• Conditions being treated.
• The established name of the drug and active ingredient.
• Dosage prescribed or used.
• Duration of treatment.
• Specified withdrawal, withholding, or discard time(s), if applicable, for meat, milk, eggs, or animal-derived food.
• Keep records for two (2) years.
• FDA may have access to these records
*BQA guidelines recommend keeping these records for all livestock treatments.
“Using FDA Approved Medications: Common Scenarios” – Mike Apley, Veterinarian & Professor of Clinical Sciences, College of Veterinary Medicine, Kansas State University; Virginia Fajt, Veterinarian & Clinical Assistant Professor, Texas A&M University and Chair of the Committee on Pharmaceutical and Biologic Issues of the American Association of Bovine Practitioners Dee Griffin, Veterinarian, University of Nebraska – Lincoln, Great Plains Veterinary Educational Center.
Extra-Label Drug Use -- An Informational Outline of the Animal Medicinal Drug Use Clarification Act (AMDUCA) – American Veterinary Medical Association.
Elizabeth Parker, DVM, National Cattlemen’s Beef Association
[September 28th, 2009]
Dr. Rick Rasby, Professor of Animal Science
Animal Science, University of Nebraska - Lincoln, Lincoln, NE