Drug residues a constant threat
Dairy farmers across the U.S. have done an admirable job of reducing the rate of drug residues in milk.
Any slip-up, however, can mean a unpleasant call from your milk handler and a potential visit from your state department of agriculture. Avoiding residues takes constant vigilance and attention to detail, says Norbert Nigon, a veterinarian with the Minnesota Department of Agriculture’s Dairy and Feed Inspection Division.
"Continuing to rely on testing cows that are known to have been treated will only keep milk residues at current levels," he says. "Most violations are caused by treated cows that had no identifying information at the time of milking to indicate that their milk was to be withheld from the bulk tank."
Follow-up visits to Minnesota farms with reports of residues in milk show that 95% of residues were caused by milking a treated cow or dry cow by mistake. And only one in seven farms tested the bulk tank before loading the milk onto a tanker or had written treatment protocols from their veterinarians.
There are seven simple steps to reduce the potential for residues, Nigon says:
1. Keep detailed animal treatment records for at least two years. Records should include cow ID, date and time (a.m. or p.m.); diagnosis, drug used, amount of drug given, route of administration (intermuscular, subcutaneous, IV or intramammary) and initials of person giving the drug.
2. Marking all cows, especially dry cows, with highly visible indicators before treatment.
3. House treated cows in a separate treatment pen.
4. Limit product treatment to 10 cc intramuscular or 15 cc subcutaneous per injection site.
5. Withhold milk for the entire prescribed withdrawal period, even if the milk test is clear earlier.
6. Test the tank before loading.
7. Check animal treatment records before any animal leaves your farm for any reason. Follow withhold periods for marketing animals for meat consumption.