by Tamara Scully
Drug residues, from antibiotics or other chemicals being given to livestock, are found in milk as well as in beef. These chemicals are “certainly problematic. If there’s a residue, then somehow that chemical got into the food,” Dr. Dwight Bruno, BSc, DVM, New York State Department of Agriculture and Markets said in a recent PRO-DAIRY workshop addressing milk quality. The workshop — the third in a three-part series held this winter — was broadcast live to various viewing locations throughout the state.
One hundred percent of repeat violators — those with more than one instance of drug residue in milk and/or in beef animals — in New York State in 2014 were cited for neomycin or other drugs in veal calves, Bruno said. This could be directly correlated to feeding bob veal calves medicated milk replacer.
“The dairy industry is also the beef industry,” Bruno reminded producers. Drug withholding times can be different for milk and for meat. On a national level, most residues seen are in beef, primarily in dairy beef, he added, urging dairy producers to consider the colostrum or milk source. Trace backs on bob veal residues often go straight back to the waste bulk tank. Live animal tests are available to test for antibiotic residues, but keeping accurate records, and using meat withholding times for dairy animals destined for slaughter, are key.
“We focus on edible tissues, but there are still big-time concerns with residues in milk, too.”
Testing today is much broader and more sophisticated than in the past, with test being run at the packing plants, and samples taken and sent to a lab in the Midwest, where a battery of tests are done on the tissue. First-time violators are sent a warning letter by the USDA/FSIS, in an effort for voluntary compliance. A second offense, however, is publically listed, available on the internet, and warrants increased government scrutiny.
Keeping up with the latest regulations, which “are a moving target, changing as we speak,” can be challenging, Bruno said. “There’s a lot that’s going on that make it complicated,” including extra-label drug use, prohibited chemicals, veterinarian feed-directive drugs and other situations where some variation from label use, under a valid Veterinary Client Patient Relationship (VCPR) is allowable under very defined circumstances.
The FDA released testing data from 2,000 dairy farms on March 5, 2015, the same day this PRO-DAIRY workshop occurred. Although the data showed that 99 percent of the milk was not contaminated with drug residues, the FDA did find that some drugs not normally tested for routinely were found, and will be modifying test protocols based on this information. It will also seek to test the bulk milk tank on farms where drug residues have been found in culled dairy cows. The agency is also focused on educating producers on preventing drug residues.
Keeping clear, concise records documenting any treatments given is key in both preventing and in defending against residual drug violations. They also serve to document herd health, and allow managers to look back and evaluate the efficacies of treatment over time, as well as cost-effectiveness and comparisons of alternative therapies.
“Records need to be written,” Bruno said. Date, animal identification, record of the drug administered, by whom, the dosage, the route of administration, and the drug withholding time should be documented clearly. Records should be kept a minimum of two years.
The FDA will want to see records, and having complete records can defend producers against animal misidentification, as well as show the FDA that an honest mistake was made, and the that the producer is trying his best to follow established treatment protocols, Bruno said. The main issues which cause residue problems are lack of treatment records, poor or incomplete records, improper drug use, and poor on-farm or farmer/veterinary communication.
“Communicate and think before you treat,” he advised “If they (authorities) think you are not listening, they’ll take action.”
Drug labels and usage
Drug labels include more than the simple instructions on the outside packaging. They also include any insert directions, as well as any veterinarian-directed instructions. Producers need to make sure “that you are aware of all of those components,” Bruno said, as all of it is collectively part of the label.
Any use that is not specifically a part of these written instruction is considered extra-label drug use (ELDU). This “off-label” use applies not only to prescription medications, but also to any over-the-counter medications. One issue of concern is ELDU of penicillin purchased over-the-counter.
“It is illegal for producers to use drugs in an EL manner,” Bruno emphasized. Examples of illegal ELDU include: changing the dose, frequency, or route of administration; using the medicine for a different disease; not adhering to the withholding time; changing the duration of use; or using the drug to treat a different animal class. The label will indicate all of these parameters for legal use.
Under the direct supervision of a herd veterinarian, there are times when the use of medications can vary from the label instructions. There must be a proven VCPR, where the prescribing veterinarian knows your herd history, your management strategies, your herd health issues, and drug use history.
Beginning in 2016, new regulations will make feed additive drugs available by prescription only. Producers will no longer be able to purchase these Veterinarian Feed Directive Drugs in feed stores without a prescription.
Illegal drugs for food animals can not be used at all, and veterinarians are aware of prohibited drugs. There are also limited-use drugs, that can sometimes be utilized off-label, under very unique circumstances, but “it’s not a clear path,” Bruno said. There has been a recent increase in drugs put on the prohibited or limited-use list, due to food safety concerns.
Another consideration that is often overlooked by producers and can result in residual drug violations pertains to the manner in which drugs are tested. Drugs are tested in healthy animals, and withholding times are based on the metabolic rates of these healthy animals. When animals are ill, their bodies may not be able to metabolize the drugs as efficiently, requiring a longer withholding period before culling the animal. Building in a buffer of time before culling after treatment, so that the drug has additional time to clear the system, Bruno advised, is prudent.