Regardless of where you live, or the type of fly control you want to implement, working with your neighbor is worth exploring.
“Right now, the industry tends to have a defensive, uncoordinated approach where individuals do their own thing,” says Allen Miller, a research agricultural engineer at the Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, TX.
With the limited number — and declining effectiveness — of chemical and mechanical tools available to producers, most experts agree a community-wide, fly-control program is a good concept. However, given the independent nature of the cattle business, it's not something that happens very often.
One of the first ways to look at a community-wide approach is to start talking. Miller suggests talking with neighbors as close as a mile from your cows. Begin by getting an idea for what they're doing to mechanically and chemically combat flies.
Management is mechanical
Mechanically combating flies is the individual practices producers can do to limit fly breeding. Miller says producers should be conscious of the way they feed hay, for instance — varying feeding locations and feeding in a way that reduces hay waste. Wasted hay combined with cattle manure provides an excellent breeding ground for stable flies.
Another is sanitation, which includes cleaning pens and lots, or altering the manure in any way possible to disturb the life cycle of flies in the material. Sanitation is at least 75% of the fly-control program in preventing fly breeding, according to Ohio State University's “Livestock and Livestock Building Pest Management,” Bulletin 473.
Most mechanical control occurs when cattle are confined. Once cattle are on pasture, it becomes increasingly difficult to mechanically control flies. Ralph Williams, Purdue University entomologist in West Lafayette, IN, recommends rotating pastures once cattle are out to grass, since horn flies breed exclusively in manure pats.
The next discussion point with your neighbor is to compare chemical control methods. These include everything from using ear tags, feed-throughs, traps, spraying animals and buildings, and dust bags, drips and other self-treatment devices.
By learning what your neighbor is doing, you can better calculate your strategies' effectiveness. For example, if you're using a feed-through product, and your neighbor isn't, you're wasting your money.
“It only takes a few manure pats to produce good numbers of horn flies,” says Nancy Hinkle, University of Georgia entomologist in Athens. “So they can continue to supply their neighbors on just a few animals.”
Selecting a strategy with an eye toward minimizing the effect of insect resistance is another issue. Miller says neighbors cooperating on fly control need to agree to alternate between classes of compounds, such as from an organophosphate to a pyrethroid or an avermectin, and back again.
“It's real important to switch classes of compounds,” says John Maas, University of California Extension veterinarian at Davis. He provides a list of registered pesticides for use in California for cattle producers there. Hinkle also has a similar listing. By providing such information, Maas says cattlemen are able to make informed decisions about what they use for fly control.
“Unfortunately, when you develop resistance to an insecticide, you develop a resistance to the entire class,” Hinkle says. A common problem she encounters with producers is they think switching brand names means they're switching classes. It's not.
So should you and your neighbor use the same type of chemical class to control flies?
“There are two trains of thought on that,” Hinkle says. “One is seasonal rotation, where you use one chemical this season and another chemical the next season. The idea is the switch in product will kill flies that survived the previous treatment.
“There's also locational rotation, so that as flies migrate between herds they're exposed to different insecticides.”
Hinkle is more in favor of seasonal rotation, though locational rotation might also work in theory. Purdue's Williams is more cautious.
“It's not necessarily a good idea for everybody to be doing the same thing, using the same product, because you don't want an area-wide resistance,” Williams adds.
Look at a timeline
Talk with your neighbor about a timeline for fly control. Miller says starting early in the spring provides better control of over-wintering flies. “If you suppress that first generation, they won't build up as rapidly,” he explains.
He suggests using an avermectin pour-on early in the spring for “double treatment.”
“Not only do you control internal parasites, but also external parasites, such as horn flies, for up to 30 days,” he adds.
Another key factor is the fly's generational interval for your geographical location. The warmer the climate, the more fly generations are produced each year. In the South, for instance, up to 16 generations of flies can be produced in one calendar year, while the Northern Plains might have only three generations. More generations means a higher propensity for development of resistance, perhaps even within a single season, Hinkle says.
Another way producers can work with neighbors is to consider buying products together, suggests Williams. “If they find something that works, they could jointly do some purchasing.”
Also keep in mind non-agricultural neighbors next to your operation. Bob Hansen, a commercial pest control operator based in Rochester, MN, specializing in agribusiness, has sprayed cattle operations at the urging of non-agricultural neighbors.
“One client was concerned that even though I sprayed his house, he was going to get a large influx from the cattle across the road,” Hansen recounts.
After talking the neighboring beef producer into spraying, both folks were happy with the results. Surprised by the difference it made, that producer is now spraying several of his locations, Hansen says.
How far can a fly fly?
Flies move for all sorts of reasons: to find food (a blood or mucus meal from your stock), better breeding grounds (possibly those pens you haven't cleaned up from the spring), and better environment.
“They'll go however far it takes to find that first cow,” says Allen Miller, a research agricultural engineer at the Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, TX.
Stable flies can easily get caught up in wind currents and move hundreds of miles, but are capable of traveling 10 miles or more on their own.
Horse flies can migrate anywhere from 5-10 miles from their breeding area (mud around ponds and lakes) to their feeding area of cattle herds.
Face flies will realistically travel up to ½ mile, preferring to spend only 10-15% of their time on any one animal before moving to another.
Horn flies, which breed in fresh cow manure, can travel easily up to a mile and as much as five miles depending on their need.
Look at the economics
Research at the Knipling-Bushland U.S. Livestock Insects Research Laboratory in Kerrville, TX, found that controlling flies on mama cows resulted in a 14% increase in calf weaning weights.
University of Nebraska research shows a 10- to 15-lb. advantage in calf weaning weights where cows had good horn fly control. Stable flies depress weight gain 0.48 lbs./day in calves and 0.44 lbs./day in yearlings.
Nationwide, annual losses in excess of $876 million are felt due to horn flies alone, while another $432 million is lost due to stable flies. Fly infestations cost the U.S. cattle industry an estimated $2.2 billion annually.