cows lined up
Flies can have a dramatic impact on the bottom line of a farm. Fly irritation results in reduced feed-conversion efficiency and poor general health.

With the frigid frostiness of winter seemingly in the rear view, we — and cattle — can now rejoice that spring has finally arrived. No more drastic temperature changes from relatively warm to teeth-chattering cold — we hope.

Warmer weather also brings back those pesky flies whose mission is to torment our beloved herds. Before temperatures begin to rise, it’s important to have a fly-control plan in place.

Unfortunately there is no way to completely rid the herd of flesh-eating flies, but there are a number of preventative measures that can be taken in the never-ending battle of fly control.

Waste management

Remove the grounds for which flies breed to see a significant decrease in the number of flying foes circling the herd. The first line of defense is creating a fly-management program.

“Buildup of organic matter is the biggest breeding grounds for flies,” said Mike Peacock, Southern States Cooperative ruminant nutritionist.

With the average 1,250-pound beef cow generating 75 pounds of manure a day, this leaves many areas for flies to reproduce.

On average, the fly life cycle lasts anywhere from 10 to 21 days. In order to break the life cycle, remove fly-breeding materials on a regular basis. Manure, wet grain, spilled silage, moist hay — focus on these areas first.

“You can eliminate a large portion of flies by simply cleaning the hay rings where cattle were fed all winter,” Peacock said.

Start by removing manure from livestock pens as frequently as possible. Take the manure and spread it thinly on fields or other large outdoor areas to facilitate drying. Flies cannot develop in dry environments; therefore they cannot develop in dry manure. Drag the fields to more evenly distribute manure. The key is to dry out the manure.

Pay special attention to areas where the herd congregates, such as water troughs, shady areas and gates. These areas should be cleaned weekly, at a minimum, to diminish fly breeding and control parasites.

Remember, it’s easier and more cost-effective to prevent fly breeding than to try to control adult flies already born. When their habitat and breeding grounds are removed, they will disappear too.

Fly predators

Not all flies are bad. Fly predators, nature’s own self-inflicted enemy, can be an ally in the fight against pest flies. These are tiny, non-stinging, non-biting wasps that feed on fly larvae and interrupt the breeding cycle of flies, destroying the next generation of flies before they hatch into disease-carrying adults.

Fly predators work by laying eggs in the fly pupa or cocoon and feeding on fly larvae while it’s in manure. The wasps “bug” the bugs but never disturb the cattle, pasture plants or humans. Although a natural method of controlling flies, fly predators aren’t typically found in large enough amounts to control the entire fly population on the farm. But many companies sell fly predators and can ship them straight to the farm. Once they arrive, all that’s needed is to sprinkle the predators on manure piles at dusk and watch them go to work.

As a rule of thumb, replenish the fly-predator supply once a month from April to September. It’s important to use them during the entire fly season; otherwise the fly life cycle will only be broken for a few weeks.

Dustbags and backrubbers

Dustbags are a low-maintenance, highly effective method of combating troublesome flies. After application, the dust will control horn flies as well as lice on beef and dairy cattle. The bags of dust are hung across gates or doorways and are easily refillable. The most effective place to hang a bag is a place where the cattle pass by on their way to their water tank. This is known as a forced-use situation.

Hang the bag low enough so it’s effective on small calves as well as adult animals. If hung and maintained properly, the bags will last for several seasons.

Cattle tend to rub up against objects when they are being pestered by bugs. The backrubber is a rubber surface that is soaked with a pesticide to deter flies.

Walk-through fly traps

Another environmentally friendly way to be rid of flies is with a walk-through fly trap. Because horn flies spend the majority of time during the summer on the backs and sides of cattle, this trap helps reduce their numbers. As cattle walk through the device, the flies are brushed off them.

Farmers’ winged adversaries can ultimately have a dramatic impact on the bottom line of a farm. Fly irritation results in reduced feed-conversion efficiency and poor general health. The stress of dealing with flies on a daily basis can result in lower birth rates and weaning rates in a herd.

“No one method alone will eliminate the problem,” Peacock said. “You have to take an integrated approach and start early.”