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Fly Control on Dairy Farms

Pest management is a never ending cycle. It seems that when one pest leaves, another takes its place. Fall and winter bring birds to the dairies, while spring and summer mean it is fly season. Flies are a costly nuisance to dairies across the country. Most of the costs are not easy to find and hard to measure. Lost profits come from:

  • Shaking, rubbing and tail switching use energy and raise heart & respiratory rates, which will increase body temperature
  • Increased grouping, which can worsen heat stress
  • Nutrients are diverted to replace blood loss from biting
  • Decreased feed quality & quantity from flies consuming the feed
  • Transmission of diseases such as mastitis, bacterial scours, and pink eye


Overall, there has been some estimation of these yearly production losses due to stable flies (Taylor, et al., 2012):

  • 306 lbs of milk per cow
  • 13 lbs of body weight from preweaned calves
  • 57 lbs of body weight from stocker cattle


This corresponds to a total loss in the dairy industry of $360 million in 2009 dollars (Taylor, et al., 2012). This lost production alone may not be enough to warrant fly control, but cleanliness and health effects also need to be considered.


Control Programs

When it comes to pest management, the sum of a program’s parts is more than any individual strategy can ever be.  The first step to using an integrated pest management program is to answer three questions:

1. What species of pests are the major problems?

2. What stage are these pests in (larvae, feeding, and reproduction)?

3. Where are the areas on the farm that are a threat (breeding areas, feeding areas, etc.)?


Next, find a method that is targeted to each one of these areas. Here are some examples and what they are targeted for.

Cleanliness & Sanitation - Flies need moisture and organic matter to feed and breed in. If they do not have these things, they will not cause a problem. Cleaning up any organic matter (spilled milk, feed, manure, etc.) will go a long way to reducing fly populations. And as a bonus, this is the cheapest management method.

Spraying - Hire a pest control agent that can use a residual spray for flies around buildings and feeding areas. This can kill adult flies as well as deter other flies from coming to the dairy. Additionally spraying cattle that are old enough and using ear tags with a fly control agent can help prevent biting flies.

Predators - Fly predators are small parasitic wasps that lay their larvae inside the larger pest fly’s larvae. This causes the fly larvae to die, and therefore help control pest fly populations. These natural predators usually live around the same breeding grounds that pest flies use. However, to maximize their potential use, introducing and sustaining populations of predator flies is necessary.

Baiting/trapping - Dry or wet bait can be used to pull flies away from certain areas and can be used with a pesticide or trap.

Larvicide - Larvicides can be used to prevent future flies. Larvicides will not get rid of current flies or the first generation of flies, but will go a long way to prevent future flies. Larvicides can be sprayed on breeding areas, such as manure storage, or can be fed. Examples of feed-through larvicides include Clarifly®, Altosid®, and Rabon™. Each has a value on farm. Rabon™ is an organophosphate that has been used for years and is still used successfully to control all four major fly pests (face flies, horn flies, house flies, and stable flies); however, some resistance to these types of products can develop over time. Clarifly® is used to control house flies and stable flies (flies common to confined cattle) and operates by not letting fly pupae develop. Altosid® is used to control horn flies (flies common to pastured cattle) and contains an ingredient that acts like a hormone in the developing pupae. Consultation with your nutritionist should be used to choose the right product given the type of fly pressure and history of fly control.


Flies cost the dairy industry production and profit across the country. Flies are attracted to dairies due to the large amounts of feeding and breeding sites that exist on any dairy. Controlling these feeding and breeding sites offer a great place to start controlling flies. But this alone is not enough. Complimentary fly control programs will go a long way to reducing fly populations, and therefore their effects on profit. These programs include spraying, baiting/trapping, and larvicide feeding.

Safety Message: Pesticide Safety-Pesticides can be dangerous and potentially deadly if not used and stored safely. Safety precautions include:

  • Use non-chemical control methods first to control the majority of flies
  • Strictly following product labels
  • Use protective measures when handling pesticides, such as proper clothing and equipment
  • Don’t spray on windy or rainy days
  • Store pesticides out of reach of children and pets, such as in a locked cabinet or shed
  • Do not place baits where children and pets can reach them
  • Educate children about the dangers of pesticides


Taylor, DB, RD Moon, and DR Mark. 2012 .Economic impact of stable flies (Diptera: Muscidae) on dairy and beef cattle production. J. Med. Entomol. 49(1):198-209.


I see you have estimated the loss to the dairy industry at $360 Million due to flies. Can you tell me what the annual cost of fly control is to the dairy industry?

Posted By Doug Vontz on 3/23/2015 3:52:34 PM

Any additional information is appreciated. Thank you.

Posted By Nick LeQuia on 2/21/2017 1:11:59 PM

Thank you for your comment, Nick! We have several other fly control articles on our websites:

Posted By Hubbard Team on 3/9/2017 2:03:58 PM



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