Insecticidal Ear Tags: What to Know About Fly Control for Cattle



Proper use of Insecticidal Ear Tags

Ear tags impregnated with traces of insecticide can provide excellent control of cattle pests like horn flies and may also limit face fly populations. University research indicated that effectively controlling these pests can increase stocker cattle gains by 15-25 pounds.

What is the best strategy to minimize the development of resistance to chemical compounds?

Pyrethroid-resistant horn flies are found in many parts of the country and developing resistance depends on many factors. Judging by the flies affecting your herd, an alternate method of control like organophosphates for one to three years followed by one year of pyrethroid use may be appropriate. And now there are two new classes of fly tag insecticides to combat pyrethroid and organophosphate resistant flies – endosulfin which has been on the market for a few years, and the newest – abamectin. Abamectin is a mixture of avermectins commonly used as an insecticide and/or anthelmintic (dewormer). Its more familiar derivatives are Ivermectin, Selamectin, and Doramectin. Abamectin provides an ideal alternative in a strategic fly control rotation.

Here are some things you can do to improve the effectiveness of your fly tag investment:

  • Apply as many tags as directed per animal, i.e., use two tags per animal when indicated.
  • Don’t apply tags too early – tag animals after horn fly populations reach 50 or more per side of animal.
  • When using fly tags in cow-calf herds, tag calves when indicated by the label instructions.
  • Use rotation to avoid resistance (alternate main ingredients).
  • Use traps, sprays, or nematodes in other areas where flies gather.
  • Remove fly tags and dispose of them properly at the end of the season. Failure to do so may be the single-largest contributor to ineffectiveness and developing resistance.

Don't forget to exercise precautions when handling fly tags. 
Use latex gloves and avoid touching your face.

This was originally posted at on Monday, May 4th, 2009.

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