Insect Pests of Beef Cattle
When cool weather arrives most of us forget about insects. However, cattle lice are cool weather pests. The lice problem starts in the fall, builds through the cold winter and peaks in the late winter or early spring. Left uncontrolled, a cow can carry tens of thousands of lice by late winter.
Our cattle are subject to attack by one species of biting louse and three (3) species of sucking lice. The biting lice eat dead skin and scabs primarily. The sucking lice suck blood and serum from cattle. The sucking lice are the most important as they take energy directly from cattle. Lice are especially important insect parasites as they infest our cattle during the season when cattle are receiving the poorest diet.
Lice are active insects, moving over the body of the cow. The itching caused by lice results in the symptoms we usually notice. Hair can be rubbed off in large patches and large areas may be rubbed until raw and bleeding. Cattle rub against trees, posts, feed-bunks and barns in a response to the itching.
November is when cattle are most often routinely treated for lice. This is a good practice for most cattlemen. However, if a systemic pesticide (such as Ivomectrin) has been used since July it may pay to wait until symptoms show-up to treat. This is because the sucking lice will have been controlled with the systemic treatment - and sucking lice are more damaging than biting lice. To follow this course, it is important that all cattle will have been treated with the systemic. If some individuals were not treated, or if cattle have been added to the herd, these untreated cattle may reinfest the others.
The most economical method of treatment is with "pour-ons" or spot-ons". Available products (tradenames) are: Lysoff, Tiguvon, Spotton, Co-Ral, Ectivan, Atroban, DeLice, Permectrin and Expar. All are effective - buy based on price. Be sure and read labels before purchasing products, because some have class and weight restrictions.