May 12, 2006
FROM UNIVERSITY OF MISSOURI EXTENSION
SOUTHWEST REGIONAL NEWS SERVICE
Contact: Eldon Cole, livestock specialist
Headquartered in Lawrence County
Tel: (417) 466-3102
E-mail: colee@missouri.edu

Many Tools Exist for Fly Control on Beef Cattle; Old-Fashioned Self-Built Fly Traps are 70 Percent Effective

A cattlemen’s dream is to have a fly-free environment for his beef cattle during the fly season according to Eldon Cole, University of Missouri Extension livestock specialist. 

Many beef cattle producers consider flies as the worst pest because they can transmit diseases (especially pinkeye) and they suck blood from cattle, which reduces gains and milk production.

A variety of tools – such as sprays, pour-ons, dust bags, back rubbers, boluses, feed additives, traps and ear tags – can be used for fly control. Even if all of these tools are used in a herd, a producer can still expect to see a few flies on the cattle.

THREE TYPES

“It’s almost impossible to eliminate all flies, but you should be able to keep the numbers below a threshold level. For example, horn flies should not exceed 200 flies per head. That is a high number, but research shows animal gains are not reduced up to that level,” Cole said.

Face flies are known to transmit pinkeye so their control is critical in herds with pinkeye problems, but they are difficult to control. 

“Face flies are not blood feeders and even heavy infestations do not reduce gains unless pinkeye is involved. These just appear to be a problem when 15 or 20 are feeding on the secretions around the eyes and nose,” Cole said.

A third species of fly is the stable fly (also blood feeders) which attacks the lower front legs of livestock. As few as five stable flies per leg has reduced cattle performance. Horse flies and deer flies are also blood feeders that can inflict heavy losses. 

FLY CONTROL TOOLS

Fly control decisions vary with pasture setups, labor and personal choices. Cole says that over the years, a well-placed, self-treating device (a dust bag or back rubber) offers the most effective, lowest cost horn fly control system. 

He recommends a location where cattle will come in contact with it daily. Several effective pesticides are available in both dust and liquid form (the latter is mixed with fuel or mineral oils).

“I hear lots of reasons that a self-treating device won’t work in certain pastures, but where there’s a will, there’s a way. Place the bag or rubber near the salt feeder, at entry ways to water, in a lane or close to shade for fairly regular contact, if not daily,” Cole said.

The fly tag may have seen its best days due to the resistant fly buildup, but there are some fly tags on the market that still work according to Cole.

“Pyrethroid fly tags are probably the best way to control face flies. Just don’t put them in too early in the season. Most of the tags state they give from three to five months control,” Cole said.

Feed additive for fly control is useful for those flies whose larvae develop in manure (horn flies and face flies). Since flies can come from neighboring herds, feed additive control may require supplemental control such as sprays or back rubs.

BUILD A FLY TRAP

The most novel method of fly control remains an old-fashioned walk through trap, which gives up to 70 percent horn fly control. These traps are sometimes used by persons not wanting to apply pesticides. They remain effective, but Cole says few are ever built anymore.

Guide sheet G1195, “Walk-through trap to control horn flies on cattle,” as well as other guide sheets about controlling flies on livestock, are available at University of Missouri Extension centers in every Missouri county or online at http://muextension.missouri.edu/explore.

“The total, fly-free herd probably won’t exist and probably should not, but some attempt should be made to keep flies under the threshold numbers. Keep an eye on them early, consider the expense involved and see if an extra 15 or 20 pounds of gain over the fly season can justify the dollars invested,” Cole said.

For more information, contact any of the MU Extension livestock specialists in southwest Missouri: Eldon Cole in Mt. Vernon, (417) 466-3102; Gary Naylor in Dallas County, (417) 345-7551; and Dona Funk in Cedar County, (417) 276-3313. 

University of Missouri Extension is your one-stop source for practical education on almost anything. Extension programs focus on the high-priority needs of people throughout the state. Each county extension center, with oversight by locally elected and appointed citizens, is your local link to these unbiased resources and programs.
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