Preventing Antibiotic Residues – April 2018

April 2018 Newsletter PDF

Preventing Antibiotic Residues

One of every producer’s biggest fears is having a drug residue found in the milk or meat from their farm. Before the planting seasons begins, take the time to review the systems you use to prevent drug residues and make sure everyone on the farm understands as well. The risk of a residue can be very low if everyone understands and systematically follows the process.

Once a cow has been treated with a drug, no matter where it was given, it is distributed throughout the body. The body will begin to break down the drug, sometimes fast, sometimes slowly. The pieces then exit the body through different means, like the milk or urine. The withdrawal time that is established for each drug is how long after the final treatment that it takes for the cow’s body to break down and eliminate the drug so that what is left is below the maximum established threshold allowed. Withdrawal times depend on the kind of drug used, the dose, how it was given, how often and for how long, as well as the age of the cow and her health. Healthier cows clear drugs from their bodies faster than sick or thin cows. Milk withdrawal times are often shorter than meat withdrawal times because it takes longer for the drug to leave muscle tissue than mammary tissue; the drug exits the body every time a cow is milked.

Use the following practices laid out by the National Dairy FARM Program and the New York State Cattle Health Assurance Program (NYSCHAP) to prevent drug residues.

Establish a Valid VCPR. In a valid Veterinary-Client-Patient Relationship (VCPR) a veterinarian (RVVC, we hope!) is regularly visiting the herd and discussing animal management and health issues. The veterinarian assumes the responsibility for making medical judgments and is readily available for follow-up care in case treatment fails or there is an adverse reaction. The vet also establishes antibiotic use protocols and an approved drug list and reviews them with the client. The client in turn agrees to use the protocols and follow the vet’s instructions.

Proper Drug Use on Farm. Use only prescription (Rx) drugs or FDA-approved Over-the-Counter (OTC) drugs, with a vet’s guidance. All drugs should have their product labels and the drug inserts available. Drugs with labels for use in specific groups (lactating, non-lactating, <20mo of age) are used only in their approved groups.

Only vets can prescribe drugs in an “extra-label” manner. Extra-label use is where a drug is administered in a use that deviates from what is specified on the printed label. This could be a difference in the disease being treated, the dose, the duration or how its given. Some extra-label drug use is allowable under certain circumstances and some is illegal in food animals.  Your vet knows which is what. Extra-label use often involves a prolonged withdrawal time.

Records. Maintain a record-keeping system for all treated cows, and make sure all treatments are recorded immediately after they are given. Treated animals should be identified with a leg band or marked in some other way to indicate a treatment was given. Regularly review the records with a veterinarian and use them to identify potential issues and reduce the risk to milk quality.

Every treatment record should contain the following:

  • Identity of the animal being treated
  • Drug given
  • Reason it was given
  • Route of drug administration
  • Dose given
  • Who gave it
  • Meat and milk withdrawal times and dates when the meat and milk can be used for milk again
  • If treatment was prescribed/recommended by a vet

Drug Storage. All drugs for lactating and non-lactating cows are stored separately and well labeled, with nothing being stored in the milk house. All prescription drugs should have a label with information about the prescribing veterinarian. Throw out expired drugs.

Testing. Make sure to test every cow before her milk goes back in the tank, especially any cow that was treated in an extra-label manner. Dry cows that freshened early should be tested as well as any new cows entering the herd before adding their milk to the tank. Never decrease the meat or milk withdrawal time from what is on the label. While the meat can’t be tested on farm for residues, follow a premarket/slaughter checklist to review treatments and withdrawal times to be sure the cow is free of drugs. If two antibiotics were used in combination, their individual withdrawal times should be combined and that number used as the withdrawal time.

Training. Discuss all protocols and recommendations from the vet with employees and family and have regular training sessions for everyone on preventing milk and meat residues.

For the full materials on drug residue avoidance, go to the National Dairy FARM Program website ( or the NYSCHAP website ( Below is a chart of common drugs and their risk factors for residues. Your vet is also an excellent resource on proper drug use; its part of our training. Plus, with your VCPR, we should be helping you with protocols and correct drug use practices anyway!

Common Drugs and their Residue Risk Factors

Drug NameTrade NameRisk for Residues
CeftiofurCeftiflex, Excede, Excenel, Naxcel, Spectramast-Using a withdrawal time from one product when using another.
-All have different withdrawal times!
-Keep accurate records of the exact product used
-All have different approved routes of administration and can’t be used otherwise
EnrofloxacinBaytril-NO Extra-Label use!
-Only use to treat dairy animals <20mo of age or beef animals for pneumonia. Nothing else.
NorfenicolNuflor-Only for dairy cattle <20mo or beef
-Single dose treatment has a longer meat withdrawal than the 2-day treatment
-No amount is tolerated in dairy cattle
Flunixin meglumineBanamine-IV only! Cannot be given IM or SQ
PenicillinPenicillin-Increased dose, frequency or duration of treatment requires increased withdrawal time
-Giving more than 10mL per injection site requires increased withdrawal time
TetracyclinesOT100, LA200, PRO 300LA-Large-volume injection in one site
-Extra-label use such as giving as an infusion for an infected uterus
-Long meat withdrawal time


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