Sound sanitation practices are key to managing flies in dairies. (Photo by Robert Waggener)

Entomologists like Dave Boxler occasionally receive SOS calls from dairy farmers or feedlot operators chomping at the bit with fly outbreaks.

Tours of such facilities typically result in an SOS back to the farmer: shortage of sanitation.

“Sanitation is the No. 1 issue,” says Boxler, who is stationed at the University of Nebraska–Lincoln’s West Central Research and Extension Center in North Platte.

“Sanitation is the key to reducing fly numbers.”

But Boxler says that sanitation requires effort, and because of that some producers rely too heavily on management techniques that take little time.

“It’s much easier to jump into a rig and drive around the facility with a mist blower than it is to carry out a sound manure- and moisture-management program,” Boxler says. “It’s not uncommon to see operators relying too heavily on pesticides.”

Boxler, who has worked in research and Extension for 40 years, quickly takes a step back because he understands the demands of running a dairy or feedlot.

“Producers have a lot of things to do during the day, and that is very evident when you tour an operation,” he says.

Boxler, however, believes that carrying out an integrated fly-management program will bring dividends in a variety of ways: happier cows, more milk production, fewer disease outbreaks, happier workers, less insecticide resistance and happier neighbors.

“People get real irritated real fast when flies are migrating into their residential neighborhoods,” he says. “So the owners of dairies and feedlots need to be aware of that and manage fly populations the best they can.”

This starts with regular clean-up of manure, spilled feed, old bedding, etc.

“When you manage manure and waste successfully, that is the key to keeping fly numbers very, very low,” he says.

Manure can be piled into mounds and covered with plastic tarps, which will generate enough heat to kill developing fly larvae. Another effective method is to leave the piles uncovered but turn them every 10 to 14 days, which will break the fly lifecycle.

The resulting compost can be spread on farm fields or sold. And some dairy operators are working out deals with the farmers they purchase feed from. When a truckload of silage comes in, it leaves with a load of manure.

Boxler encourages operators to regularly inspect water tanks and lines to ensure there are no leaks. “Flies need moisture to develop, so you want to maintain your dairy lot as dry as you can.”

Regardless of how aggressive producers are with sanitation, he adds, “There are going to be times you may not be able to successfully control flies, given weather or whatnot, and that’s when you’ll have to come in with an insecticide treatment, such as a mist or premise spray.”

To ensure success today, tomorrow and next year, he emphasizes, “Read labels carefully and alternate between the insecticide classes to better manage insecticide resistance. During the fly season, rotate on a monthly basis.”

Other effective tools include fly baits and parasitic wasps, says Boxler, who also encourages producers to watch for proven technologies to hit the market.

“A colleague of mine at North Carolina State University, Dr. Wes Watson, developed a device called the Cow•Vac. It’s essentially an industrial-sized vacuum cleaner designed for animals that are accustomed to being worked, and dairy animals are certainly that.”

When cows are walking through a chute toward the dairy parlor, they pass through the Cow•Vac, which sucks flies off their backs, bellies, legs and faces without causing harm to the animal.

Any more out-of-the-chute tips?

“I hate to be redundant,” Boxler replies, “but sanitation is the key.”