Three Tips to Get the Most out of Your Pour-on Dewormer

Develop an effective deworming program that keeps cattle comfortable and reduces resistance.

“Let’s face it. We aren’t going to have an unending supply of new molecules and new active ingredients for parasite control,” warned Dr. John Davidson, senior associate director, beef cattle professional services, Boehringer Ingelheim. “That’s why we need to ensure judicious and proper use of the products we have available now — to ensure they maintain their efficacy in the years to come.”

Dr. Davidson said there are several best practices for getting good parasite control from pour-on dewormers:

1. Compare product labels and choose a dewormer that:

  • Controls a broad spectrum of species and stages.
  • Is weatherproof (in case it rains following application).
  • Is nonflammable (if you will be branding cattle).

2. Properly administer pour-on dewormer:

  • Ensure facilities are equipped to adequately restrain animals, so that there is minimum movement.
  • Determine each animal’s weight, using scales whenever possible.
  • Calculate the volume of pour-on product to be administered, based on each animal's weight.
  • Apply the product with an applicator gun along the midline (over the top of the back of each animal). Begin at the withers, and pour all the way down to the tailhead. Make sure the entire dose gets on the animal, not on the sides of the chute or on the handlers.

3. Dosing done right:

Follow the label. In doing so, you have the greatest likelihood of achieving the appropriate drug levels to kill the parasites. This means that the dosage — or the amount of product applied — is adequate for the size and weight class of the animal being treated.

  • Under-dosing: If an animal is under-dosed, the product’s active ingredient is not present in the animal’s tissues at the necessary level, and the product will not deliver its desired effect. Under-treatment will likely leave some of the parasites behind. That becomes problematic because the surviving parasites are potentially more likely to be resistant to subsequent and future treatments with products in a similar class.
  • Overdosing: When you overdose animals, you waste hard-earned dollars on product. Generally, the safety index for this class of products is fairly broad, so toxicities as a result of overdosing are rare.

Proper dosing ensures that the drug will be available — in the necessary concentration — in the animal’s tissue, so it is effective against the species of organisms that it is indicated for. Simply put: You need to deliver enough of the drug to kill the parasites that you’re intending to kill.

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