How to Kill Lice on Cattle

A cattle rancher's profits are only as healthy as his livestock, and protecting his animals from lice and other insects and parasites is an important part of keeping his cows healthy. Mild to moderate infestations of biting lice (Mallophaga) can cause a cow to lose weight due to discomfort, and severe cases of sucking lice (Anoplura) can cause anemia, which also leads to weight loss. If your herd of cattle is infested with lice, follow these steps to rid the herd of the offending critters.

Things You'll Need

  • Pour-on dewormer
  • Spray or dust insecticide
  • Insecticide dust bag
  • Insecticide ear tags (optional)
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Instructions

    • 1

      Assess the severity of the lice infestation by examining the face, neck, back, dewlap and tail base of the cows. Lice are about 1/16 inch in size and scatter quickly. The dead bodies of Anoplura lice can leave an oily substance on the animal's coat. A matted-hair coat could be caused by Mallophaga eggs. Cows with lice often rub themselves raw.

    • 2

      Treat all cattle with a pour-on dewormer, such as ivermectin or moxidectin. These parasiticides provide long-term protection against lice and should already be a part of your deworming program. Follow the directions on the package label, because all brands require different dosages.

    • 3

      Provide protection between dewormings by regularly applying a dust or spray-on treatment. Permethrin is the most common active ingredient; however, some insects have shown resistance. So, for severe infestations, you may want to consider products containing diflubenzuron, cyfluthrin, an organophosphate or an added synergist. Again, each product has different instructions for use, so read the label carefully.

    • 4

      Prevent reinfestation by treating all new cattle entering the herd. Contact across fence lines can even spread lice. Hang insecticide dust bags, and refill them with permethrin regularly, so itchy cattle can seek lice-killing relief. You can also purchase insecticide ear tags that discourage flies, ticks and lice for one to five months.