Fly Control in Beef

Source: Allison Wright, ANR Extension Intern for Wright, McLeod and Meeker Counties. Reviewed by Karen Johnson, UMN Extension Livestock Educator for Wright, McLeod and Meeker Counties. 320-484-4303. ande9495@umn.edu

As fly season is just beginning, an important question to ask yourself as a livestock producer is if your fly control methods efficiently worked last year? According to the University of Nebraska, a controlled fly population should have an economic injury level (EIL) of 200 flies per animal for horn flies and 5 flies per leg for stable flies. This may seem like a fairly easy number to achieve but without extra methods of fly control treatment the population will grow. The three main fly types that affect grazing beef production are the horn fly, stable fly, and the face fly. 

The horn fly is the smallest of the three. This fly is easy to see on the backs, belly, and sides of the cattle. The horn fly has a life cycle of 10 to 20 days. Horn flies are blood sucking flies and can acquire at a minimum 30 blood meals per day. Economic losses from this fly are more than $1 billion dollars annually in just the United States alone. Some of these losses are caused from a decrease in weaning weights up to 4-15%, and weight gain loss in cattle. Tail switching, head throwing, and bunching are all behaviors of cattle affected by horn flies.  

The stable flies are also a blood feeder but are found on the legs of the cattle. This fly is bigger than the horn fly. The stable flies have a life cycle of 14-24 days. The economic losses from the stable fly can account for up to 0.44 lbs of daily gain loss per animal. Animal behavior associated with this fly is bunching, stomping, and tail switching. 

The face flies are the biggest in size out of the three flies. These are non-biting flies but feed off of the secretions, nectar, and dung liquids of the cattle. They often carry diseases like pink eye, and are found near the muzzle, eyes, and wounds of the cattle. The cattle will be twitching their ears and shaking their head if the face flies around them. 

Using one product for fly control will not be able to target all three of the fly types as the control methods for each fly are different. One precaution that can be taken to help with all three however, is to keep farms sanitary and clean. This includes: cleaning TMR piles, manure piles, spoiled feed, unnecessary water buckets and removing build-up around automatic waterers and stock tanks.  

The University of Michigan states, using at least two different methods of fly control will give the best results in an integrated fly control system. One product can be used on a once every three week basis and the second one weekly to hit both growth stages of the flies.  It is important to read the label of any product that will be used on the cattle, and make sure to look at the time in between applications. 

The following information is from the University of Nebraska. 

Horn flies can be controlled by backrubbers, dust bags, insecticidal ear tags or strips, pour-ons, oral larvicides, low pressure sprayers, and mist blowers sprayers. All of these methods have to be applied more than once a fly season, each of these average a reapplication time of once every 3 weeks. 

Stable flies are controlled by keeping the farm site sanitized and clean, larvicides, and sprays that are applied once a week. 

Face flies are effectively controlled by dust bags, oilers, sprays, and insecticide impregnated ear tag/strips.

Depending on the size of your beef operation, fly control measures can take time to administer, but they outway the negative outcomes if not treated. Like the old saying goes “an ounce of prevention is worth a pound of cure.”

If you have any questions regarding Fly Control in Beef, please contact your local University of Minnesota Extension Educator or the University Extension Beef webpage.