Dairy regulators recently launched a new pilot program to watch for tetracycline traces in milk on July 1. The new monitoring program will test milk for tetracycline antibiotics such as oxytetracycline, tetracycline and chlortetracycline.
The tolerance level set by the Food and Drug Administration (FDA) for tetracyclines in milk is 300 parts per billion.
At the National Conference of Interstate Milk Shipments (NCIMS) in 2015, the pilot program was established to expand testing for drug residues. Since then state and federal dairy regulators, with industry input, have spent the last two years developing the new pilot program to go live.
“It is very similar to the beta-lactam program,” says Beth Briczinski, vice president of dairy foods and nutrition for the National Milk Producers Federation (NMPF). “NCIMS built this pilot program to mirror the beta-lactam program.”
Currently, every bulk milk tank truck is tested for beta-lactam drugs such as penicillin, ampicillin, amoxicillin and cephalosporin to name a few. Just the same as the beta-lactam residue testing, any tanker found with a tetracycline drug residue violation will be rejected and the milk is to be dumped.
According to Briczinski, the tetracycline screening program will run for 18 months. During that time, all Grade A milk processing facilities, including those manufacturing fluid milk and yogurt, are expected to participate in the pilot program. Plants that process cheese and butter may also participate. Those in the tetracycline pilot program will be required to test at least one out of every 15 milk tankers that pull up to a processing facility. From the selected trucks a sample of milk will be taken and tested for tetracycline residues with the same type of test strips and technology used for the beta-lactam drugs. Over the next 18 months, it is expected that nearly all dairy farms will have their milk tested at some time for tetracycline.
“At the end of the 18 months, NCIMS is going to sit down and take a look at the data,” Briczinski says. “At that point, they are going to decide if the pilot program will continue and become a formal program.”
The ultimate goal of the tetracycline pilot program is to demonstrate the effort the industry is doing to ensure antibiotic residues do not end up in milk, Briczinski says.
“We hope the tests show that the dairy industry is doing a great job in how we manage drugs on our dairy farms,” Briczinski says.
According to Jamie Jonker, vice president of sustainability and scientific affairs for NMPF, another objective of the tetracycline pilot program is to make sure farmers are appropriately using the various approved tetracycline drugs on their farm for treatment of animals in need.
“Ultimately it is the responsibility of every dairy producer to ensure they have no residues of antibiotics in their milk,” Jonker says. “Therefore, if they are using any of the tetracycline family of drugs on their farm, they need to make sure first they are using them appropriately either as directed on the label or as prescribed by their veterinarian.”
The FDA has approved oxytetracycline to be used as an injectable drug for treatment of diseases such as pneumonia, shipping fever, bacterial scours and metritis, Jonker says. It is also approved as a topical treatment for pinkeye.
“All over-the-counter drugs must be used precisely according to the label directions from the manufacturer’s instruction for treatment: amount of drug given to the animal for the specific disease being treated, the route of administration, the length of treatment and the withdrawal time for meat and milk,” Jonker says.
Some farmers and hoof trimmers apply tetracycline powder when wrapping hooves affected by digital dermatitis (hairy heel warts). This represents a risk for milk residue under the new tetracycline pilot program.
“It is important for farmers to understand there is no FDA approval for using tetracycline administered topically to a hoof in a hoof wrap,” Jonker says. “Therefore if this is being done on a farm by a hoof trimmer, the dairy farmer must have a prescription from their veterinarian.”
Tetracycline powders are only available with a veterinary prescription and a valid veterinarian-client-patient relationship (VCPR). Farmers applying tetracycline to a foot wrap should pay close attention to the amount of the drug they apply. The more a drug is used the more risk created for a milk residue. Only a small amount should be applied directly to the lesion. Research shows a 2-gram dose is the maximum that should be applied to a wrap.
Although the attention is currently on tetracycline, at the end of the 18 months, dairy regulators may switch to a different class of drugs to begin monitoring. Their hopes are to continue testing for other drug residues using the same style pilot program.
“The pilot program is specifically focusing on tetracycline for right now, but my message for producers would be that we can’t just focus on tetracycline,” Briczinski says. “We need to look at all of the management practices we have in terms of how we handle drugs on-farm.” 
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Audrey Schmitz
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PHOTO: One out of every 15 milk tankers that pull up to a processing facility will be tested for tetracycline drug residues. Photo by Karen Lee.
