Fly Control

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It’s a common question this time of year, “What can I do to control the flies?” Producers ask what the “best” thing is for flies and when they should start using said product. Those of you who have been doing this for a long time have probably come to the conclusion that no matter what you do, there are going to be some flies.

Most people are familiar with the two main types of flies seen on cattle: the horn fly and the face fly. An easy distinction between the two is to examine where they congregate; if it’s around the horns (or poll), the side and the back, chances are it’s a horn fly. The ones that hang around the eyes and face of the animal are appropriately called face flies. Horn flies account for an almost $800 million loss in the U.S. alone; these flies have been shown to be related to irritation, blood loss, decreased grazing efficiency, reduced weight gains and a decline in milk production. Face flies are commonly attributed to the spread of pinkeye in cattle. Regardless of the fly type, there are some important things to consider when implementing a fly control program.

Pour-ons, sprays, back rubs and ear tags are common methods of fly control in this part of the world. If ear tags are used, 2 tags per animal should be used to maximize control. Delay tagging until June 1, and remove tags in the fall, to decrease the chance of resistance. Do not use insecticide ear tags until the “economic threshold” of 200 flies per animal has been observed. Make sure you check the active ingredient in your fly tags and rotate when possible to prevent resistance (for example, use an organophosphate tag for 2 years and then a pyrethroid tag for one year). There are also some insecticides on the market that can be fed with the most common of these in a mineral supplement. Back rubs can be very effective IF the animals use them. They should be placed in areas where the cattle will go often, i.e. near the food, water or mineral supply.

The method in which you control flies can have a huge impact on the effectiveness; pour-ons and sprays only provide limited amounts of control and will have to be reapplied during the season. Insecticide ear tags provide longer control. The key to remember, as with anything else, there is no clear cut way to do something. There is no “best” way to prevent flies in your herd. An integrated approach to fly control may be your best bet!