The buzzing of a fly is enough to kickstart a bad mood. Imagine how cattle must feel with hundreds of them swarming on their faces, backs and legs. You may have missed the window to start fly control early, but there still are measures you can take to protect your cattle through the rest of the summer.

The thing about fly control is that there is no right answer. Every operation is going to look a little different, and what controls flies on one farm could be ineffective on another farm. Ron Lemenager, a beef cattle specialist and professor of animal sciences at Purdue University, shares that it is best to take a comprehensive approach, aiming to control all types of flies.

Find what works

Depending on which flies are present — horn fly, stable fly, house fly, face fly or a combination of those — some fly control measures will be more effective than others. Some producers may only have one or two types of flies, so it may just take one control measure. Lemenager says to find what is effective and keep using that method.

“If you’re getting good control of the flies you’re concerned about with one method, then you can stick to that without adding a second method,” Lemenager says.

The first step to fly control is maintaining clean buildings, lots and pastures. Manure, decaying plants and rotten feed are perfect breeding grounds for house flies and stable flies. Keeping the facilities dry and clean will mitigate some of the fly pressure before it becomes a problem.

Typically, topical or pour-on insecticides can achieve almost total control of horn flies and some control of face flies. This method will show quick results, so it would be a solid choice if you’re looking for immediate control.

With topical applications, it’s key to apply the total recommended dosage to avoid building resistance. Lemenager adds that knowing the weight of your animals will help ensure you are administering the correct amount.

Another effective control method for face and horn flies is self-applicators. These consist of dust bags, back rubbers, face strips, mineral feeder covers and fly bullets that contain insecticide. The key to using this method is putting the applicator somewhere that the animal would be forced to use it, such as an entrance to a building, water, shade or a chute.

More options

Feed-through products, or insect-growth regulators, are another piece to the fly control puzzle. However, this method will not show immediate results. Lemenager recommends pairing feed-through products and another method, such as topical applications, for immediate and long-term control.

“With the IGR products, you have to go through a life cycle,” Lemenager says. “That could be 12 to 28 days. So, if you start feeding an IGR product late, don’t expect to have good control immediately. It’s going to take a while for that product to work.”

Another fly control option is ear tags containing insecticide. As they wear out, it’s best to bring in an additional fly control method. “That’s a situation where you might use a pour-on insecticide to control through the rest of the season,” Lemenager says.

Avoid these mistakes

While Lemenager suggests leaving the ear tags in for the rest of the season, there is a point where you can do more harm than good if they are not removed. He notes that some producers keep tags in throughout the winter, which contributes to resistance. They should be removed after the first killing frost.

“Fly season is over at that point, and you don’t want to have just a small amount of insecticide that will not kill some of these flies,” Lemenager says. “The ones that break through are the ones that are going to be resistant.”

Dewormer should not be used as your main method of fly control. Some topical dewormers offer partial fly control, but a mistake Lemenager sees is producers not using the full dose, which fuels resistance of both flies and internal parasites.

“You might get reasonable fly control, but you will start to create some resistance of your internal parasites,” Lemenager says. “That is not a recommended practice.”

One additional mistake to avoid is using products with the same mode of action each season. Over time, this will generate resistance and make the products ineffective in your herd. Lemenager recommends switching the mode of action each year, or even for each application.