Preventing drug residues in milk continues to be a key area that dairy producers should focus on, but starting on July 1, 2017, that prevention will develop another layer. The tetracycline screening pilot program will begin, and no less than 1 out of 15 tanker loads of milk will be tested for oxytetracycline, chlortetracycline, and tetracycline. The tolerance level for the drug will be 300 ppb.
This testing pilot program represents an opportunity for dairy producers to re-evaluate how the tetracycline class of drugs is used on the farm. Oxytetracycline injectable is labeled for the treatment of bacterial pneumonia and infectious bovine keratoconjunctivitis (pinkeye).
Many producers may use oxytetracycline in an extra-label indication for treatment of mastitis, metritis, or topically for the treatment of digital dermatitis (hairy heel warts). Under the direction of your veterinarian, extra-label drug use is legal as long as established withdrawals periods are adjusted when necessary.
Many producers, veterinarians, and hoof trimmers use the tetracycline class of drugs to wrap feet affected by digital dermatitis. This represents a risk of milk residue under the upcoming tetracycline screening pilot program. Wrapping a foot with tetracycline (powder or injectable) and not withholding milk puts the producer at risk for a milk residue violation.
FARAD (Food Animal Drug Residue Avoidance Databank) recommends a 24-hour milk withhold when a cow’s foot is wrapped with tetracycline. While tetracycline foot wraps aren’t directly affected by the veterinary feed directive legislation, the powder tetracycline product switched from over-the-counter to prescription status on January 1, 2017.
Tetracycline powders are only available with a veterinary prescription and a valid veterinary/client/patient relationship. Anyone applying tetracycline to a foot wrap should pay close attention to the amount of the drug they apply. More drug creates more risk for milk residue. Only a small amount should be applied directly to the lesion. Experts have suggested that a 2 gram dose is the maximum that should be applied to a wrap.
Smaller herds need to be even more diligent in monitoring and obeying milk withhold guidelines due to the lack of dilution factor. While larger herds may be at less risk, they should still obey the withhold guidelines on all tetracycline products to maintain the integrity of the milk they sell. Ultimately, the dairy industry can’t justify improper drug withholds based simply on dilution.
This program should also renew the producers’ commitment to lameness in general and digital dermatitis specifically. This is an excellent time to review footbath protocols and scrutinize heifer facilities. We know that it’s critical to prevent hairy heel warts prior to first calving. Often times, cleanliness is a critical step in preventing digital dermatitis in heifer facilities.
While producers may view this new testing protocol as additional level of regulation, consider it another step in improving the quality and safety of the product that the dairy industry has to offer. Antibiotic use needs to be transparent on our dairies.
This program is another way for the industry to open the blinds and let the public see what we are doing to care for cows and provide a safe product. As long as the tetracycline class of drugs are used properly, the dairy industry will have nothing to hide.
Note: This story appears in the June 2017 issue of Dairy Herd Management.