Don’t Let Pests Fly Away With Your Profits

There is no specific date to mark on your calendars for when flies will begin to be a problem. But rest assured, they will emerge, and they will most likely become an issue for your cattle.

The Problem

Flies are pests that drain cattle of nutrients through bloodsucking while also transmitting a variety of diseases. Fly damage costs the U.S. cattle industry an estimated $1.5 billion annually, of which horn flies alone make up $850 million¹. That can equate to approximately $30-50 per head/per year loss for the average producer¹. A horn fly feeds about 20-30 times on each animal per day, which equals approximately one pint of blood per animal/per day. This can result in a 13-14% decrease for the average daily growth rate of nursing calves². Flies also cause constant stress to the animals as they must defend themselves against the biting, which in turn weakens their immune system and makes them susceptible to diseases such as anaplasmosis and pinkeye.

Flies can cause:

  • Blood loss
  • Reduced grazing efficiency
  • Reduced weight gain
  • Reduced milk production
  • The spread of disease and parasites


Depending on temperature and humidity, a horn flies life cycle can be completed in 8 to 45 days. These files will rest on an animal, sucking blood and potentially transmitting diseases, until they are disturbed to move or go to lay eggs in the animal’s manure, which in turn creates more flies to deal with.

So how do you combat these pests and maintain your profits?

The Solution

As with most things, it’s better to be proactively ahead of the situation than to wait until there are issues to resolve. With that in mind, here are a few steps you can take to protect your herd – and in turn, your profits.

  • Remove potential fly breeding grounds from the area your cattle are in.
  • Keep the barn areas clean.
  • Remove spilled feed that could become damp.
  • Reduce moisture in pastures – improve drainage around problem areas like water troughs.
  • Feed an animal treatment – and start it early! (30 days before the first frost)
  • maps and guidelines are from Central Life Sciences

Furst-McNess has three products that are designed to be used in an integrated pest management system. The products available include:

  • Altosid® IGR – only available in AR, AK, FL, GA, IA, MO (availability is subject to change) and is to be blended into products
  • ClariFly® – available to be blended into a product or mixed on-farm
  • Rabon® 7.76% – available to be blended into a product or mixed on-farm

Below is a listing of the features and benefits of these products:

Mineral Options

Bova Beef 6 – Altosid® IGR: A mineral designed to be used on grass and mixed legume grass-based forages that prevents adult horn flies from emerging from manure of treated cattle.

Why worry about controlling horn flies more than other flies?
  • Horn fly infestations can reduce weaning weights by 10-25 pounds per calf³, reduce growth rates in replacement heifers 13-14% 2 and reduce daily gains in yearlings and stockers by 0.2 pounds per day³. Milk production can be reduced by 10-20%⁴

Will Altosid® feed through kill adult horn flies?
  • No, its made of action inhibits the development of horn flies in cattle manure, stopping fly development in the pupae stage before they mature into harmful adults.

Does Altosid® IGR feed through harm dung beetles and other beneficial insects?
  • No, not when used according to the label directions.
  • Horn flies have developed resistance to pyrethroid and/or
  • organophosphate insecticides, what about Altosid® IGR feed through?
  • There has not been a verified case of fly resistance to Methoprene since the technology was introduced in 1975.

Will Altosid® feed through harm horses?
  • Horses have been experimentally dosed with Methoprene without adverse clinical signs or loss of appetite *.

Should I worry about horn flies in feedlot cattle or in a dairy where cows are kept in barns or dry lots?
  • No, horn flies and face flies are range or pasture pests and rarely do they become pests of livestock in confined areas.

What does it cost me to treat my cattle with Altosid® IGR feed through?
  • Altosid IGR usually costs $0.03 to $0.05 per day. When all costs of treating with other insecticide applications are considered it is very comparably priced. For example, with pour-ons, costs of shrink, depreciation of equipment, time and labor must be combined into the price of application.

What are the benefits of IGR?
  • Helps to keep condition on cows by reducing stress and activity associated with biting flies
  • Improved weaning weights – research indicates calves wean 10-25 pounds heavier when fly control is successful
  • Affects horn flies that are unresponsive to other fly control products
  • Safe for all cattle and the environment

Fescue Fly Force Premier-YC: Contains high levels of trace minerals that are more available, essential oils that have been shown to increase water intake and Equalize Beef to help manage feed quality and support reproduction.

All-Natural Option

Bova-Min 6-Fly: An All-Natural option of highly fortified mineral that contains the fly control technology used in Fescue Fly Force Premier. This product is available in the following states: AR, AK, FL, GA, IA, MO (availability is subject to change).

* – Data on file
¹Stephen Belzinger, “Causes, costs and effects of flies in beef cattle,” Progressive Cattlemen, February 24, 2017
²DeRouen, S.M., L.D. Foil, A.J. MacKay, D.E. Franke, D.W. Swanson and W.E. Wyatt. 2008. Effect of Horn Fly (Haematobia irritans) Control on Growth and Reproduction of Beef Heifers. J. Econ. Entomology
³R.L. Byford, M.E. Craig and B.L. Crosby, “A Review of Ectoparasites and Their Effect on Cattle Production,” Journal of Animal Science, Vol. 70, p 599
⁴Bruce, W.N. and G.C. Decker. 1958. The relationship of stable fly abundance to milk production in dairy cattle. J. Econ. Entomol. 51(3):269-274

McNess Fly Control Economic Worksheet