It is the time of year when cattle are seen rubbing on trees, fence post, feeders or anything they can. They will rub until the skin becomes raw, thick and irritated and often the cause for this is lice. It costs cattle producers millions of dollars in losses each year. They are biting the lice, which live on their skin and hair. These are a sucking lice. Sucking lice tend to cause anemia, which will cause the immune system to become weaker leading to other illnesses. The lice will cause a decrease in weight gain and in milk production, and this will lead to an increase in feed costs and cause you to treat other issues resulting in less profit.
The problem occurs in cooler  weather. It is increased when the stress of cold rain and wet conditions occur. The best prevention is included with a deworming program. The Ivermection, Avermectin and moxidectin products when used as a pour-on will control lice for approximately 90 days. If a producer uses one of these products early in October or November, they may still see lice in January or February therefore, a pretreatment may be needed.
I like to deworm with injectables in October, then use the pour-on when the first cows are seen rubbing. Sometimes it may be late December or mid January; then I prefer to use a pour-on with an Ivermectin, Avermectin or moxidectin due to the fact I have less retreating. If I use some of the other pour-ons, like organophosphates or premectrin, another application may be indicated in four to six weeks.
I tell producers to follow the instructions of those products. I also believe it is very important to treat every animal in the pasture at every treatment to prevent any cross contamination of the parasites. It is also very important to quarantine or treat any new additions before adding to the herd. This decreases the chance of a retreatment.
Treating early, using good prevention, will save on added feed and other drug expenses. It may look like only hair loss but it is actually money loss.
See your local veterinarian for the best treatment and prevention in your area. There has been some lice resistant to some of the insecticides on the market. Your veteranrian can help you determine what products work best.
Dr. Rusty Waide, DVM, has been the owner of Buffalo Veterinary Clinic for 21 years.

OFN Site ManagerOn-Call / VetMissouri,On CallIt is the time of year when cattle are seen rubbing on trees, fence post, feeders or anything they can. They will rub until the skin becomes raw, thick and irritated and often the cause for this is lice. It costs cattle producers millions of dollars in losses...The Ozarks' most read farm newspaper, reaching more than 58,000 readers in Missouri, Arkansas and Oklahoma