Ask the Vet

By Dr. Ken McMillan
DTN/The Progressive Farmer Contributing Editor

QUESTION:

I feed a mineral containing an insect growth regulator (IGR) for fly control. My supplier told me the Veterinary Feed Directive (VFD) would no longer allow him to sell a mineral with an IGR. I usually start feeding this in early spring. What should I do for fly control this year?

ANSWER:

There is confusion around this issue, and it won't be the last time as we all learn how the VFD works in the real world.

It's possible the mineral you've used in the past has more than an IGR in it. If it also contains an antibiotic, perhaps chlortetracycline (CTC), then your supplier is correct. However, if the mineral only contains an IGR, you do not need a VFD. Nothing substitutes for reading the label here.

As for the VFD, only antibiotics listed as "medically important" by the FDA and administered in feed (which includes minerals) or water fall under the provisions of the VFD. IGRs, ionophores and coccidiostats (including lasalocid, monensin and decoquinate) are not covered by the rule. Keep in mind they must be fed in legal combination.

(AG)

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