The U.S. Food and Drug Administration may have backed off its initial milk testing aims for drug residues now, but the idea remains a possibility down the road.

The agency is still interested in looking at many different drugs in the milk of dairy cows because they have seen a number of different drug residues in the meat from cull dairy cows, says Dale Moore, Washington State University director of veterinary extension.

“One drug that commonly pops up in cull-cow testing is the sulfa class of drugs,” she explains. “It can be a little confusing as to which drug you can use in which group of animals, but the information you need is on the product label.”

Following a series of five residue avoidance meetings across the state of Washington, it became apparent to Moore and her colleagues that confusion exists as to the use of the various sulfa drugs.

To help avoid sulfa drug residues on your dairy, follow these five commandments of sulfa drug use on your dairy:

  1. Thou shalt not use any sulfa drug off-label. That means NO extra-label use in dairy cattle.
  2. Though shalt NEVER use sulfamethazine in lactating dairy cows.
  3. The only injectable sulfa drug you can use in lactating dairy cows is sulfadimethoxine. The only uses (indications) on the label are for pneumonia and foot rot. A veterinarian cannot prescribe this drug for any other disease or condition.
  4. Sulfachlorpyridazine may be used in non-lactating dairy cattle. The same drug as a powder can be used for calf scours.
  5. Sulfadimethoxine can be given to lactating cows, as per the label, but sustained release products CANNOT be used in lactating cows or calves to be sent for veal.

“The most common reason for seeing a sulfa residue in a cull dairy cow is the extra-label use of sulfadimethoxine, which is labeled for lactating dairy cows, but cannot be used ‘off-label’,” says Moore. That means no different route of administration, no different dose, no different duration of treatment and is only to be used as indicated on the label.

“The single-most important things for dairy farmers and dairy hospital crews to do is to know what the label says and follow label directions,” concludes Moore.