August 15, 2008 - Sheep producers worried about another bluetongue outbreak in Montana now have permission to use three products against the insect that transmits the disease. One product, normally used on cattle, is an ear tag that contains insecticide. The other two are insecticide sprays.

Greg Johnson, a veterinary entomologist at Montana State University, said the Montana Department of Agriculture recently approved the PYthon ear tag, GardStar 40EC spray and Permectrin CDS, an insecticide spray that contains piperonyl butoxide, an additive or synergist to enhance its effectiveness.

Johnson and two Wyoming researchers tested the products last summer on sheep owned by the University of Wyoming (UW). The insects -- also known as 'no-see-ums' because they're so small -- came from a colony of biting midges that belong to the U.S. Arthropod-borne Animal Disease Research Lab in Laramie, Wyo. Working with Johnson were Jack Lloyd, a retired professor from UW and veterinary entomologist, and Will Reeves, a research entomologist with the U.S. Department of Agriculture.

The scientists found that ear tags and spray used individually prevented bites and bloodshed for three to four weeks, Johnson said. Used together, they were effective for more than four weeks.

Montana's bluetongue outbreak occurred in early August last year in deer, antelope and sheep. The outbreak was severe enough that 16 counties, most of them in eastern Montana, were placed under quarantine. Producers in those counties couldn't ship their lambs to market from about Sept. 1 through early October. Bluetongue also killed 250 sheep in Wyoming's Big Horn Basin.
Reprinted in part from MSU News Service

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