You could almost hear an audible sigh of relief last month when the Food and Drug Administration (FDA) released its long anticipated—and feared—drug residue study.
The good news: The total rate of violation was 0.7%. FDA sampled milk from nearly 2,000 dairy farms and found drug residues that exceeded tolerance or safe levels on just 15 farms.
The bad news: All of the residues came from drugs that are not approved for use in lactating dairy cows. And one, Ciprofloxacin, is prohibited from use in any food animal.
Another, Sulfamethazine, is prohibited in lactating dairy cattle and cannot even be used in an extra-label manner, says John Middleton, professor of food and animal medicine and surgery at the University of Missouri’s College of Veterinary Medicine. In addition, there are no injectable forms of Gentamicin approved for use in dairy cattle, he says.
“Florfenicol (Nuflor/Resflor), Tilmicosin (Micotil) and Tulathromycin (Draxxin) are all used for treatment of bovine respiratory disease caused by certain bacterial pathogens in beef cattle and can be used in younger dairy stock, but none have a label for lactating dairy cattle,” Middleton adds.
Florfenicol, Tilmicosin and Tulathromycin can be used in an extra-label manner with a veterinarian’s prescription. But the veterinarian would have to justify why a labeled drug for use in adult dairy cattle wouldn’t work, Middleton says.
Ceftiofur (Excenel, Excede, Naxcel), Ampicillin (Polyflex), Sulfadimethoxine (Albon) and Oxytetracycline (LA-200) are all examples of products labeled for some causes of bacterial pneumonia in lactating dairy cows.
The question remains: Why are unlabeled drugs being used in lactating dairy cows? Are these farmers intentionally trying to do an end run on the beta-lactam tests that are conducted on every tanker? And what’s the answer? More education? More testing?
Increased testing will undoubtedly get a thorough hearing at the National Conference on Interstate Milk Shipments (NCIMS) meeting in Portland, Ore., next month, says Beth Briczinski, vice president of dairy and food nutrition for the National Milk Producers Federation. The NCIMS governs the
Pasteurized Milk Ordinance, which in turn spells out rules for milk residue testing.
But simply increasing the number of tests run on milk before it is accepted for processing is no simple exercise. If you’re going to test for Florfenicol, which accounted for 10 of the 16 positive residues, you need an approved test. Currently, there is not a rapid Florfenicol test that gets results in less than 10 minutes.
The problem, of course, is if you don’t test, you undermine consumer confidence. Perhaps consumers will take comfort in the fact that FDA has found no antibiotic residues in the 160,000 samples of retail-ready dairy products it tested over the past four years. Perhaps.