Unlike hogs, cattle or chickens, lactating cows raised for their milk don’t receive antibiotics unless they’re actually sick. This is because the residue will immediately turn up in their milk, which is a violation of food safety laws for dairy farmers.
Milk shipments are tested for six of the most commonly used antibiotics and any truckload that fails is rejected. That’s why when cows are treated for illnesses, the milk is often discarded until the residues disappear from their system. But some dairy farmers may be breaking the rules, according to NPR.
A new FDA report found some farmers are slipping through the cracks by using antibiotics not included in standard testing. What's worse, they’re not supposed to be used in dairy cows at all (even when the cows are sick). NPR says that out of 31 different drug samples from 2,000 dairy farms, half of the farms were under suspicion for sending cows with antibiotics in their system to slaughter.
According to the FDA:
Samples were collected from dairy farms with a previous tissue residue violation (targeted farms) and from a comparable number of randomly selected dairy farms that were not selected for inclusion in the targeted list (non-targeted farms).
One antibiotic in particular called Florfenicol was the most common, but five other drugs detected are not approved by FDA for lactating cows. Two of the drugs are completely illegal, but the case is murkier for the other drugs.
According to NPR:
In the case of other drugs, he [Mike Apley, a researcher at Kansas State University's College of Veterinary Medicine] says, the situation is more complicated. It's illegal for farmers to use those drugs on their own, but veterinarians are allowed to authorize their use in dairy cows under certain strict conditions. Veterinarians also are supposed to ensure that no residues enter the food supply. For whatever reason, that veterinary safeguard didn't work in these cases.
The FDA says the violations are still relatively uncommon, considering one percent of samples collected contained drug residues (though the agency said it’s still working on the problem). It may start testing a larger number of farms and for a wider number of antibiotics.
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Image of a cow via Shuttershock