Lice in Cattle

The time to prevent a lice infestation in your cattle is now. Remember that many products require two applications to be effective. Photo by Amanda Lester.

As autumn quickly approaches and the temperatures begin to decline, producers need to consider what type of lice control to initiate. Cattle lice cost producers millions of dollars each year in decreased weight gains and reduced milk production.

The life cycles of the different species of cattle lice are very similar. The life cycle begins with the female attaching her egg to a shaft of hair. The egg will hatch as a small replica of the adult. After several molts, the adult will emerge. The cycle takes around three to four weeks to complete. These newly hatched lice will spend their entire life on the host and are host specific, which means cattle cannot be infected with lice from other animals.

Small numbers of lice may be found on cattle in the summer, but high population of lice are associated with cold weather. Since cattle tend to be in closer proximity to each other in the winter, lice can spread easily between cattle. A small percentage of cattle tend to harbor larger numbers of lice. These animals are sometimes referred to as “carrier animals,” and they may be a source for maintaining lice in the herd. As with many other diseases, stress also contributes to susceptibility and infestation.

Signs that cattle might be infested with lice are hair loss, unthrifty cattle, and hair on fences or other objects. If producers find these signs, they may want to check a few animals. They can check for lice by parting the hair and observing for the number of lice per square inch. If an animal has one to five lice per square inch, they are considered to have a low infestation. Cattle with six to ten would be considered moderately infested. Any cattle with more than ten lice per square inch are heavily infested.

Learn more in the October issue of Oklahoma Farm & Ranch.