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Flies can wreak havoc on herd health and profit margins. With a solid, fly management plan, your cows can be grazing forage instead of fighting flies.
On the Fly
According to Lee Townsend, extension entomologist for the University of Kentucky College of Agriculture, horn and face flies are the top two enemies of cattle.
“The horn fly will spend virtually all its life on cattle while feeding 20 to 30 times a day taking a small amount of blood each time with its sucking mouthparts,” Townsend said. “Horn fly control can mean an additional 12 to 20 pounds of weight per calf over the summer months in some cases and can result in less weight loss per nursing cow.
“The face fly uses sponging mouthparts to feed on protein-rich fluids from the eyes especially, but will visit wounds. Face flies have also been implicated as a vector of the causative organism of pinkeye, but, while face flies are not the sole means of transfer, intensive face fly control is part of an overall management approach.”
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Townsend said both these flies breed only in fresh cow manure in pastures.
In addition to cattle health and economic loss, Ken Kelley, regional extension agent with animal sciences and forages of the Alabama Cooperative Extension System said flies cause cattle to spend more time walking, lying, resting and standing instead of grazing.
“Physiological responses to increased fly numbers for cattle include higher heart and respiration rates, higher body temperatures, greater urine output and reduced nitrogen retention,” Kelley said.
Prepare the Plan
Once you’ve targeted the problem flies, a few options for control include insecticide impregnated ear tags, back rubs with face flaps, dust bags, bullets, sprays, pour-ons and minerals with an insect growth-regulator. Since flies can develop resistance to chemicals over the years, Kelley recommended rotating chemicals.
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“Insecticide-impregnated ear tags probably do the best job of delivering insecticide on a consistent basis without having to work the animals on a repeated basis,” Kelley said. “Of the insecticides used, it’s important to rotate the pyrethroids and organophosphates and, for ear tags, the recommendation is usually two years of organophosphates and one year of pyrethroids.”
The objective for a fly-management plan is to save labor, cost, cattle health and profits while being diligent with maintenance like removing the ear tags at the end of fly season to prevent fly resistance. If you include cattle-operated controls like back rubs, bullets and dust bags, recharge and refill these regularly.
“If you are going to use an insect growth-regulator which is designed to break the fly hatching cycle, it would be best to use back rubs or spray the cattle first since the insect growth regulators (IGR) won’t kill adult flies,” said Cindy Sanders, Director of Livestock at the University of Florida and IFAS Alachua County Extension in Gainesville, FL.
Time Flies When It’s Not Managed
Doug Gibbs and his father, Wendell, time their cattle confinement time so they can combine fly control with other animal health care needs. With their 500 brood cow operation consisting of Simmental, Angus and Sim-Angus breeds in Ranburne, the Gibbses gather the cattle in spring for a comprehensive animal health program including fly control.
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“During mid-May to the end of May, we vaccinate, worm and pregnancy check our cows,” said Doug, operations manager of Gibbs Farm. “During this time, when fly populations are beginning to get higher, we put ear tags in.”
Each May, Gibbs alternates permethrins and organophosphates in the ear tags to keep the flies from building a resistance to the chemicals.
“In the following fall, when we round up the cattle for breeding, we make sure to remove all the ear tags and this prevents the flies from becoming resistant,” Doug explained.
During the May round-up, the Gibbses also get early fly control through their cattle wormings.
“The pour-on back wormer we use keeps flies down for around 30 days,” Doug said. “Also during May, we vaccinate the cattle with a broad spectrum pinkeye inoculation.”
On the Move
The Gibbs’ frequent, rotational grazing has been a successful, natural way to fight the flies.
“The cows have often been moved to another paddock before the flies have had a chance to come out of the larvae stage in the cattle manure,” Doug said. “We clean our holding area regularly and spread the manure across pastures to reduce fly numbers around the barn.”
Sanders said rotational grazing helps break the cycle for horn flies.
“Since the horn flies prefer fresher manure for laying their eggs, this breaks the pattern somewhat of the fly hatching,” Sanders explained.
The Gibbs use back rubs and bullets around their feeding structures in their bull pens with success, but they don’t use them in the general cattle population.
“It’s not efficient for us to keep back rubs fully-charged in each paddock since we change the cattle to a new paddock each week,” Doug said.
Need a Back Rub?
In addition to fresh ear tags, pinkeye vaccinations and regular worming, you can use the cattle’s natural movement to help in the fly fight. Fully-charged back rubs placed in areas where cattle are naturally confined or funneled add an additional layer of fly protection. P.H. White (www.phwhite.com) carries a line of back rubs and face flaps that effectively transfer fly control chemicals to the cattle.
The simplest method of installing a back rub is between two posts in a gap or gate opening where the cattle are forced to enter. Areas like the hall of a barn offer additional protection against the elements that can wash the solution from the rub. Even if the back rub is placed between two posts out in the elements, a simple structure can help shed the rain.
Once the 10-foot rub has been attached to the posts with rope through the loops at each end of the rub, attach a two-by-six plank across the top of the posts. Next, attach a piece of long, plastic like the liner on a salt feeder to the plank. Even in a downpour, this simple structure will shed rain.
To charge the backrub, White recommended spraying a mixture of insecticide and diesel fuel with a three-gallon sprayer with the nozzle tip removed for a free flowing stream.
“Two gallons of mixture will saturate the back rub for cattle use,” White said. “About every two weeks, recharge the rub because you want the base of the back rub to feel greasy.”
Recharging of the back rub usually only takes about a gallon of solution. If face flyps are attached to the back rub, gravity draws insecticide into the fabric strips. This gives extra protection against face flies. Dust bags and bullets placed strategically around feeding troughs or confined entrances can give added fly protection.
Doug said he knows the fly tags work well because, when they wear out at the end of the summer, he sees cattle seeking relief by running under low hanging limbs and heading for shade.
“Fly control is absolutely essential,” Gibbs stated. “You loose important weight gain and reproductive strength when the cows are stressed with flies.”
When the weather gets warm and the flies start to swarm, you’ll be ready with proven fly control techniques.
Visit your local Co-op for all your fly control needs.
John Howle is a freelance writer from Heflin.
The rule of thumb is at least 100 flies per side means productivity may suffer.
Your local Co-op can provide you with advice and plenty of fly control products.
Doug Gibbs applying a wormer to a confined cow.
