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There’s no universal solution for fly control

How well did your fly control program work last year? If control was less than ideal, consider a different method. DrNutritionDr. Jim White
MFA Director of Nutrition
Many options are available to help manage the three species that economically impact cattle: horn flies, face flies and stable flies. While similar in some ways, each type of fly has characteristics that make its control slightly different from the others.

Horn flies are small pests that cause a big concern for livestock producers. Economic losses are estimated at around $1 billion annually in the United States alone. Horn flies feed on blood, irritate the animals and deposit their eggs in fresh manure. In warm weather, horn flies complete their life cycle in 10 to 20 days. Horn flies travel and can go for miles in search of a host. Even with excellent management practices and prompt manure removal, new horn flies might move in.

Horn flies spread summer mastitis, decrease grazing efficiency, reduce weight gains and lower milk production. Studies show mother cows dealing with horn flies have calves with weaning weights 10 to 20 pounds less than animals not under pressure. Horn flies can also cause yearling cattle to weigh up to 18% less.
Despite these issues, aggressive treatment is not always warranted. If horn fly numbers are less than 200 per animal, you should be fine. Above 200 merits additional fly control measures.

To combat horn flies, there are a number of insecticide options and delivery methods. Dust bags and backrubbers/oilers are effective if cattle are forced to use them. Pour-ons and mist-blowers can control horn flies for one to three weeks and will need to be reapplied during fly season. Insecticide eartags can last all season if applied relatively late. If placed earlier, they will need to be reapplied or additional fly control measures will need to be taken mid to late season.
Insect growth regulators are fed through cattle and impact developing larvae in manure. When using IGRs, continual consumption is needed for effective control. A standard MFA product with an IGR is Ricochet FesQ Max Altosid Shield Mineral.

“Each type of fly has characteristics that make its control slightly different from the others.”

Regardless of delivery method, be sure to cycle through insecticides with different modes of action. Prolonged use of one category of insecticide leads to genetic resistance in fly populations.

Face flies closely resemble house flies except they are slightly larger and darker. These nonbiting flies feed on the secretions of cattle and other animals. Female face flies cluster around the animal’s face, especially the mouth and eyes, and can spread pinkeye. With this disease, face flies serve as the vector rather than the infectious agent itself. Economic losses from face flies can be substantial, not only from pinkeye infections but also lowered weight gains and reduced milk production.

Face flies are tricky to control because they spend much of their time off the animal. Producers need a multifaceted control program that includes dust bags, oilers, sprays and insecticide eartags. When using eartags, remember to place them on both adult animals and calves to achieve the desired effects. If pinkeye is a problem, consider vaccinating your herd.

Stable flies are serious pests to dairies, feedlots and pasture cattle. They painfully bite cattle, mainly on the legs, and feed on their blood. Stable flies cause dramatic reductions in daily gain for cattle. While a threshold of 200 horn flies per animal is needed before it becomes economically important to stop them, it only takes five stable flies per animal to cause harm.

Stable flies deposit their eggs in decomposing organic matter. Old manure, urine or waste feed provide a welcoming environment for them. Sanitation and cleanup of wasted feed is the best method to reduce local larval development.

The only adult management option available to control stable flies on range cattle is use of animal sprays. These can be applied using a low-pressure sprayer or mist-blower. Weekly applications will be required to reduce fly numbers.

Visit with the livestock specialists at your MFA or AGChoice location to help plan the best fly control program for the pests that are bugging your operation.


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