The Center for Veterinary Medicine, a branch of the Food and Drug Administration, is responsible for ensuring that animal drugs are safe, effective, and manufactured with the upmost quality.
The agriculture industry and veterinary profession as a whole are trying to promote more responsible drug usage. There is a lengthy process involved with animal antibiotic approval and human safety is the key component to this.
To ensure safe consumption of animal-derived products, a withdrawal period is required prior to slaughter or milk delivery. A withdrawal period reflects the minimum length of time from administration of the last dose of medication through the time that it is safe to use meat or other animal-derived products. The purpose of the withdrawal period is to safely ensure that agriculture commodities do not contain residues of pharmacologically active substances in excess of the maximum residue limit. The United States Department of Agriculture, USDA, houses a database on maximum residue limits for more than 425 pesticide and veterinary drug residue tolerances in hay, feed, grains, oilseeds, poultry, eggs, meat and dairy. This database can be accessed online and is available to all producers through the USDA website.
Every federally approved drug or animal health product has a withdrawal period printed on the back of the product label or package insert. Labels may describe withdrawal specifications under “Residue Warning” near the bottom of the label. The withdrawal period may describe approved length prior to slaughter, approved uses of medication in beef, lactating, and non-lactating cattle, and many other specifications. The FDA has strict guidelines that require, by law, both producers and veterinarians to maintain records of administration verifying compliance with guidelines. A lot of research is required to develop withdrawal periods; if a drug is used at an incorrect dosage or for an off-label illness, the withdrawal period can be dramatically affected.
Withdrawal periods may be extended when combinations of drugs are used due to the amount of time necessary for the product concentration level in the tissues to decrease to a safe, acceptable level. In these situations, a consult with a veterinarian would always be justified. It is important to use antibiotics for their intended purpose. There are several different variations in bacteria and they may require a different class of antibiotics for treatment. If the dosage of the antibiotic is high, it may require a longer withdrawal period and giving antibiotics at a lower dose can promote resistant bacteria populations. Anytime a producer has questions regarding dosages, diseases and withdrawal times, veterinarians are there to help. Reach out to your local vet to ensure high quality production standards are achieved.
Once milk has been collected from producers, each bulk milk tank is tested for antibiotic residues. Any product with residues above tolerable levels is condemned and whoever administered the product is put on a probationary period. The USDA considers this a serious matter. The same is true with carcasses for slaughter. A USDA inspector is present and randomly selects carcasses for testing of antibiotic residues.
Another concern amongst both producers and consumers arises around antimicrobial resistance to medications. Antimicrobial drugs include all drugs that work against a variety of microorganisms (bacteria, viruses, fungi and parasites) and antibiotics are drugs that are effective solely against bacteria. To clarify, all antibiotics are antimicrobials, but not vice versa. One of the main concerns situated around antibiotics is resistance to drugs for both humans and production livestock.
The FDA has developed changes to some of its policies with regard to protecting livestock from becoming antimicrobial resistant. Antimicrobial resistance occurs when bacteria become immune to the drug used to fight them. Effective Jan. 1, livestock producers are no longer able to purchase medicated feed over-the-counter if it contains antimicrobials that are important for human health. In addition to this change, producers also cannot use antimicrobials in feed for growth promotion or feed efficiency; meaning that the use of these products with the intent of making an animal grow at a faster rate or using less food to gain weight is prohibited. The changes made by the FDA and CVM only affect the medically important antimicrobials used for human medicine.
For questions regarding antimicrobial resistance, reach out to a local USDA office or veterinary practice. Medicating livestock is not a matter to take lightly and with appropriate precautions and administrative practices in place, producers can provide consumers with top-notch agriculture commodities.
