Dr. Larry Hawkins, Senior Technical Service Veterinarian, Bayer Healthcare, Animal Health

Nobody likes flies and ticks. But for cattle producers, pests can be more than just a nuisance.

These insects can wreak havoc on the productivity of your cattle operation, transmitting disease and disrupting feeding (and ultimately animal weight gain). Studies have shown that horn flies can cost about 12 to 15 pounds in weight gain, which can have a significant impact on the bottom line.

This season, we anticipate normal to high insect pressure based on the typical seasonal patterns seen to date. It is important to begin treatments at the beginning of fly season. Once populations have become high, some of the damage is done, but the cattle can still be protected for the rest of the season.

To get in front of pest problems before they become an issue, it is important to understand the various insects, their impact and most importantly, how to defend your operation against them.

Knowing your flies

One of the biggest misperceptions about pest control is that all flies are alike. This can be true in terms of killing adult flies but not when it comes to attacking the source. To provide the most effective control, you need to know what type of insect you are dealing with, their feeding habits, breeding areas and preferred resting areas.

  • Horn fly—The primary threat from horn flies is reduced weight gain and spread of disease. This is because a single biting horn fly can take blood meal from a calf up to 40 times a day. Studies show heavily infected yearling cattle can gain 15 to 50 pounds less than those where horn flies are controlled.
  • Face fly—The face fly spreads bacteria (Moraxella bovis) that can cause pinkeye. Pinkeye causes very painful eye lesions that cause the animal to avoid sunlight, so they aren’t grazing and aren’t gaining weight. Cattle with pinkeye routinely sell for $10 to $12 less per hundredweight than healthy calves.
  • Stable fly—The stable fly can lead to cattle bunching, which may cause heat stress in animals. Studies also have shown decreased weight gain of 0.48 pounds per day.
  • House fly—The house fly can be a nuisance to you, your family, your workers and your neighbors. Not only is the house fly a pest in this sense, it also is known to transmit at least 65 disease-causing organisms.

Learning about ticks

While flies can present some serious issues on a cattle operation, ticks can be bothersome bugs as well.

Ear ticks have been shown to be a significant problem in the southwestern United States, including New Mexico, Arizona and southern California. Texas also is a prime area for ticks, especially ear ticks. Ticks can not only spread blood borne disease by taking blood from one animal to another, but when the inner ear is involved, the animal’s balance is affected. This leads to cattle that stagger and lose their balance, much like people with inner-ear infections.

Defending your operation

One of the most effective ways to defend you operation and your cattle from potentially damaging pests is to divide your operations into four key treatment areas. These include:

  • On animal—This treatment focuses on targeting pests that want to take blood meal from your livestock such as horn flies and ticks. This makes your cattle ground zero for pest damage, and these pests can be controlled by using on animal treatment. On-animal treatments include ear tags, pour ons, on-animal sprays and dusts.
  • Facility—Facility and pen premise treatments allow you to target flies in the areas where your cattle feed and rest. This creates a prime location for pests to pass from one animal to another. Treating your facilities targets reducing the number of pests bothering your livestock. Facility treatments include premise spray, dusts and baits.
  • Environmental—Focusing on environmental treatments includes targeting flies in the areas around your facilities. Pests use the areas beyond the immediate housing facilities to breed. Treating potential pest breeding areas that surround your livestock buildings, horse stables and feed storage areas with premise sprays and baits may play a significant role in reducing the pest population. Spilled feed also should be cleaned up to prevent it becoming a fly breeding area.
  • Feed through—Several species of flies lay their eggs directly in manure. Feed through insecticides kill fly larva as the eggs hatch, before they can mature and continue the cycle. With the use of an oral larvicide, you can make a proactive effort toward disrupting the fly’s life cycle.

Rotating active ingredients to address resistance

Rotation is important to minimize the development of resistance in insecticides. Pests can develop reduced susceptibility to an active ingredient over time. To help prevent this, it is important to consider rotating to a product that uses a different mode of action (MOA) every year or so, depending on the situation. An effective rotation strategy alternates between products from completely different MOA groups, not just between different brands or active ingredients from the same chemical class.

Modes of action available include:

  • Pyrethroids—Sodium channel modulators that disrupt the normal flow of sodium ions.
  • Organophosphates—Cholenesterase inhibitors that prevent the breakdown of acetylcholine.
  • Neonicotinoids—Acetylcholine receptor agonists that mimic the action of acetylcholine.

Limiting pests’ exposure to any one insecticide MOA helps sidestep the potential impact of cross-resistance and helps reduce selection pressure for resistance by any mechanism, minimizing the emergence of new resistant pest populations.

Use what fits your management style, but be sure to keep your method of fly control active.

For more information on MOA, check out this training module: http://www.bayerlivestock.com/show.aspx/education/training-tools/defense-point-training-modules/module-3-mode-of-action

Keeping safety in mind

Finally, be sure to read the label and know what personal protections equipment is required for the products being used. Also, be sure that the employees applying these products are trained in the proper use of each product and the use of the appropriate equipment.

This article was supplied by Bayer Healthcare Animal Health and was edited by DroversCattleNetwork staff for space considerations.


Campbell J. (2006). Horn fly control on cattle. The University of Nebraska-Lincoln Extension, Institute of Agriculture and Natural Resources website. Available at: http://www.ianrpubs.unl.edu/epublic/pages/publicationD.jsp?publicationId=549. Accessed February 1, 2013.

Neel JB, Burgess G, Hopkins F. Controlling parasites of beef cattle improves performance and value. The University of Tennessee Institute of Agriculture website. Available at: http://utbfc.utk.edu/Contents%20Folders/Beef%20Cattle/Health?Publications/ControllingParasites.254.pdf. Accessed October 11, 2012.

Campbell JB. (2006). Stable fly control on cattle. The University of Nebraska Lincoln Institute of Agriculture and Natural Resources website. Available at: http://ianrpubs.unl.edu/pages/publicationD.jsp?publicationId=547. Accessed May 13, 2013.

Campbell JB, Thomas GD. Beef cattle handbook: house fly and stable fly management in and near livestock facilities. The Iowa State University Extension and Outreach Iowa Beef Center website. Available at: http://www.iowabeefcenter.org/Beef%20Cattle%20Handbook/Fly-management.pdf. Accessed May 13, 2013.

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