Keep your dairy and feedlot cattle happy and healthy with a sound fly-control program. (Photo by Robert Waggener)

“Dave, would you mind giving a sermon on the manure mount?”

David Taylor starts laughing. Like other entomologists who have chased flies their entire careers, he has maintained a good sense of humor.

“I gather you might be calling about stable flies and manure. Right?”

Once the conversation gets through the sermon-on-the-manure-mount banter, things get downright serious real fast.

Studies show that stable-fly infestations in individual dairy-cattle herds lead to annual losses of 306 lb. of milk per animal, says Taylor, a USDA Agricultural Research Service research entomologist based in Lincoln, Neb.

And annual per-animal weight losses in pastured stocker-and-feeder cattle operations average 57 lb. and 20 lb., respectively.

That’s bad news for beef- and dairy-cattle producers, but there is some very good news, and this goes back to the manure sermon. Fortunately, this particular talk isn’t a one-hour sleeper. Instead, it’s just three words: cleanliness, cleanliness, cleanliness.

Stable flies lay their eggs in moist, rotting vegetative material mixed with cattle manure or urine. So the take-home message is simple: Producers who keep their feedlots, dairies and pasture-feeding operations clean will have the upper-hand on stable-fly outbreaks and their costly consequences.

“I have seen populations of stable flies congregating along water troughs so high that cattle stand 30 or 40 yd. from the trough just bawling because they can’t get to the water,” Taylor says.

He and other scientists who have studied stable flies encourage producers to mound manure and remove it from a lot at least once every two weeks.

“Stable flies will only develop in the top 6″ to 8″ of the manure, which means that if manure is spread across a feedlot or dairy there is a lot more surface area for flies to develop,” he says.

Producers are also encouraged to clean up hay rings, spilled feed along feed bunks and cast-off silage from silage pits. And don’t forget about other areas of the operation, like fence lines and water troughs, where manure can easily accumulate.

But no matter how diligent producers are when it comes to cleanliness, there will still be fly problems. Dr. Larry Hawkins, technical services veterinarian for Bayer Animal Health, says there are a number of effective solutions, including premise insecticides and ultra-low-volume mist sprays.

“It’s not uncommon to see two outbreaks of stable flies: one in late spring and another in late summer/early fall when temperatures are cooler,” Hawkins says. “This is a good time to be diligent with not only cleanliness but monitoring. And we also recommend working with neighbors. Get everyone on board to be most effective.”

Taylor agrees, noting that if neighbors are not being diligent about stable-fly management, efforts by a producer carrying out a sound, integrated pest-management plan will be reduced and, in some cases, even negated.

“Stable flies are generally an area-wide problem, and we have found that producers, by and large, don’t understand this,” says Taylor, emphasizing the importance of teamwork—with neighbors, veterinarians, Extension entomologists, company sales representatives and others.

“Monitoring is always very important because we have found that the economic impact level of stable flies is only five flies per front leg,” Taylor adds.