Wisconsin farmers are being asked to keep an eye out for lice on their cows. Dairy experts say studies show animal lice are growing resistant to the treatments used to get rid of them. They say animals should stop itching within a couple days of application, but some are continuing to exhibit symptoms. Experts say they want to sample any cow lice they can find to get to the bottom of it. UW Extension dairy expert Heather Schlesser is asking any farmers who suspect they have resistant lice on their cattle to contact her immediately so she can come and collect samples.