Food Safety, Drug Residue Avoidance Module

The New York State Cattle Health Assurance Program, NYSCHAP, is committed to educating farmers on Best Management Practices to improve the health and productivity of their animals. This includes giving them the tools they need to produce wholesome, safe and affordable milk and beef.

There is a public perception that antibiotics are used indiscriminately on livestock operations and that this use should be drastically curtailed. Several groups, including the American Medical Association and CDC, feel there is wide spread non-judicious use of antibiotics on livestock operations and that such use is contributing to the development of bacteria that are resistant to medically important antibiotics. Over the past few years, the number of antibiotics available for use in cattle has decreased. It is our responsibility to review our antibiotic use policies and ensure that they meet prudent use guidelines.

Despite all preventive efforts to keep production animals healthy, some cows have to be treated. We should be prepared to treat animals that are likely to respond and return to the herd as productive herd members. In addition to judicious treatment practices, we need to think about the safety of the milk and meat that we market from treated animals. No one wants to sell adulterated food that may present a hazard to public health and hurt marketability and product quality reputation. In the end, the judicious use of antibiotics and other drugs to treat livestock, is a win-win approach; not only do we save on the cost of drugs that are used unnecessarily, but also on labor, records keeping and discarded product costs.

Always read and follow label directions and work closely with your herd veterinarian to avoid both milk and meat residues. The primary objectives of prudent antibiotic use are to maintain our ability to use antibiotics to treat the sick, continue to have a market for milk and meat and to protect the food supply from residues.

Animal Drugs

There are three classes of animal drugs: Over-the-counter (OTC), Prescription (Rx) and Veterinary Feed Directive (VFD). Definitions for these are listed on our "Definitions" section. Using any drug in a manner that is not specifically listed for on the label is called "extra-label drug use" (ELDU). ELDU is regulated by the FDA under the Animal Medicinal Drug Use Clarification Act (AMDUCA) of 1994. Using any drug in an extra-label manner is illegal unless it is specifically recommended under the guidance of a veterinarian working in the context of a Veterinary-Client-Patient Relationship (VCPR). There are no legal extra-label uses of VFD drugs.

Milk Antibiotic Residue Testing

The Grade "A" Pasteurized Milk Ordinance (PMO), contain rules which state regulatory agencies use to implement their Grade "A" milk programs. The PMO requires that all bulk milk tankers be sampled and analyzed for beta-lactam drug residues before the milk is processed. Customers (e.g. Processors) may require additional testing for quality assurance purposes. Any tanker found positive for a beta-lactam residue is rejected for human consumption.

The good news is that the number of antibiotic residues in milk is very low. Recently just 0.017 percent of bulk---milk tankers, one in 6,000 loads, showed any sign of antibiotic residue. A decline from an already low level of 0.061 percent in 2002, a 75% improvement in the last decade (according to the National Milk Producers Federation).

Meat Drug Residue Testing

The United States Department of Agriculture (USDA) Food Safety Inspection Services (FSIS) conducts tests for chemicals - including antibiotics and various other drugs, pesticides and environmental chemicals - in meat, poultry, and egg products destined for human consumption.

Scheduled sampling plans consist of the random sampling of tissue from healthy-appearing food animals. The development of scheduled sampling plans is a process that proceeds in the following manner: 1) determine which compounds are of food safety concern; 2)use algorithms to rank the selected compounds; 3)pair these compounds with appropriate production classes; and 4) establish the number of samples to be collected.

The FSIS HACCP program implemented at slaughter facilities identifies the animals most likely to have drug residues. Animals that display lameness, injection site lesions or signs of illness are targeted for testing. If there is any doubt about the potential for drug residues in an animal, they should be withheld from market. In 2010, inspectors collected 90,921 samples from market dairy cows to test for drug residues. Confirmed violations in suspect animals consisted of phenylbutazone, Flunixin, and antibiotics. In July 2012, FSIS instituted a new multi-drug testing methodology and sampling program for testing of meat, milk and eggs.

The new testing protocol will cover not only antibiotics but also pesticides and environmental contaminants in those animals pulled aside in its inspector-generated testing program. Each year, nearly 3 million adult dairy cows are slaughtered for beef. Of that amount, a very small percentage test positive for a residue. Over the past few years, USDA has made several changes in its residue screening program including implementation of the KIS test which is more sensitive than earlier tests and increasing the number of tests conducted on dairy market dairy cows. In spite of these changes, the number of tissue residues in market dairy cows has decreased by 55% since 2007. If the animal looks sick, it will be targeted for drug residue testing. However the risk of violative tissue residues should be minimized if treatment protocols are carefully followed and approved lactating animal drugs are used for the class of animal being treated. If treatment records are well maintained and proper doses, routes and frequency of administration are heeded; the risk of violative tissue residues will be minimized.

Also, in 2008 0.0001 percent of beef cattle carcasses tested positive for drug residues. However, 0.03 percent of dairy beef carcasses were found with residues. The dairy industry must realize that 90 percent of drug violations in beef come from either dairy cull cows or bob veal calves. It should be a goal of dairy producers everywhere to strive for zero cases of residue in both milk and meat.

The avoidance of milk and meat residues in the dairy industry takes an on-farm team effort that begins with the VCPR - the Veterinary-Client-Patient-Relationship. The dairy farm owner/manager /herdsman must work with the farm veterinarian to develop treatment protocols that address the correct use of antibiotics. Once a decision is made to use antibiotics then protocols must be in place to guide employees on the safe way to handle this animal to prevent an inadvertent milk or meat residue from occurring. Identification of treated animals and recording antibiotic use are essential to prevent residues.

The regulatory tolerances for milk and meat antibiotic residues vary depending on the type of drug used and route of administration. The withdrawal times and safety tolerances are only valid if a drug is used according to the label directions AND in the class of animal listed on the label. If a drug is used in a class of animal NOT on the label, then there is NO TOLERANCE established for that drug and any trace amount, even if it is below the safe tolerance level established for the labeled class, is a violation. All of these products have a tolerance limit if it is used in the labeled class of animal.

Extra-label drug use in unapproved classes of animals is discouraged. A complete listing of the tolerances can be found in the FDA Green Book, which lists all approved animal drugs. The Green Book is available in searchable format online. When there is doubt about an animal drug residue status it is advised to consult experts that can help determine the status of the drug in the animal before it is sent to slaughter. Your herd health veterinarian is a good first resource. The veterinarian can help determine if pharmaceutical companies should be consulted or live animal screening tests employed to determine an animal drug residue status. If you have questions or concerns about potential residues or withdrawal times please contact your local veterinarian. For additional help or information the following phone numbers and websites of pharmaceutical and screening test manufacturers may also help with advice and determine residue status.

Records Management

FDA requires veterinarians to maintain records for two years of all animals treated using extra-label drugs (21 CFR 530.5). Though not a regulatory requirement, a good management practice for producers is to keep records on all animals treated with drugs. The record system should be easily accessible to everyone who works with the animals.
Records should be permanent so the veterinarian has a history to which he/she can refer to prescribe effective therapy and to serve as protection in case of regulatory follow-up. The producer needs to be able to show how all drugs purchased were used or disposed.

The treatment record should contain, at a minimum, the following information:

  1. Treatment date
  2. Animal identification
  3. Dosage
  4. Route of administration and expected duration
  5. Withdrawal time for milk and meat
  6. Individual who administered the drug
  7. Drug used
  8. Duration of therapy.

Residue Avoidance

Drug residues can be avoided by a well-planned drug use program. Reasons given for milk and meat residues result from many on-farm situations. These include, but are not limited to, the following:

  1. Lack of consultation from a licensed vet
  2. Not following vet’s recommendation when using any drug
  3. Not following manufacturer-or vet- prescribed label directions for correct treatment
  4. Not following the manufacturer or vet prescribed label directions for the appropriate withdrawal period
  5. Poor identification of all cattle including bull calves
  6. Accidentally milking a treated cow into the bulk tank or not diverting from bulk tank
  7. Long-term residue following treatment as a cal
  8. Use of medicated milk replacers in calves that may be sold for human consumption.

When multiple treatments are combined or overlapped the time to clear those drugs from an animal’s system can increase. Producers should consult with their veterinarian for appropriate withdrawal times. Animal liver function, particularly with poor animal metabolism, may not be able to keep up with multiple circulating drugs and therefore withholding times can be prolonged.


In today's environment, dairy producers need to be pro-active in how they manage their animals, farms and employees. Working with their veterinarian to produce farm guidelines for animal treatment, drug usage protocols and employee training can reduce the risk of residues in the milk and meat. The NYSCHAP team of producer, herd veterinarian, NYSCHAP veterinarian and any other consultants, or managers of the farm can use this module for risk assessment of current management practices which may lead to drug residues, and creating a specific herd plan to address these weak areas and implement procedures and training to reduce these risks. This module offers forms that can be utilized for this purpose as well as resources to keep abreast of this quickly evolving topic.

How to Enroll in NYSCHAP

To enroll in NYSCHAP, contact your herd veterinarian and ask him or her to make arrangements with the regional field veterinarian from the NYS Department of Agriculture and Markets. For additional information, contact one of the sources below:

  • Enrolling or contacting a state field veterinarian: NYS Division of Animal Industry, 585-313-7541
  • For Diagnostic testing services or information: Animal Health Diagnostic Center, 607-253-3900.