By Mike Boersma
Extension Educator, Pipestone and Murray Counties
Summer fly control is an important aspect of raising livestock. While it is challenging to assign an exact dollar value to the benefits of proper fly control, it is undoubtedly important. High fly populations are not only a nuisance; they can also lead to reduced weight gain and feed efficiency and increased incidence of diseases like pinkeye.
There are a variety of fly control options for producers and the preferred method of fly control will vary from one producer to the next. The most effective method depends on livestock species, livestock numbers, facility design/pasture size, availability of working facilities, and a variety of other factors. Often, finding a combination of control measures that work well for your management system will be the most effective way to control flies.
Insecticide-impregnated eartags are a popular option for cattle producers looking for season-long control. While these eartags can work well, it is important that producers insert tags in early summer and remove them by early fall to help avoid insect resistance to the insecticide. Also, varying the brand of tag and insecticide used will help to reduce insect resistance.
Back rubbers and dust bags also work well but they must be placed in an area that the livestock will pass through on a regular basis. This could be an open gate, doorway, or some other structure that animals must pass through. Locations adjacent to feed, water, or other areas that livestock visit regularly are the most effective.
There is a long list of pour-on insecticides for producers to choose from as well and these can be very successful. However, their effectiveness on outdoor livestock can be short-term, especially during rainy periods.
Finally, many feed companies offer mineral supplements or lick tubs that can also aid in fly control. Many of these are designed to control fly larvae in manure but may not be effective against adult insects.
Any of these options, as well as many more, can be effective in certain situations and it is important for producers to evaluate the management system that will work best for them. Regardless of which option is chosen, producers should remember to wear gloves and other protective clothing when handling pesticides. Also, some insecticides may have a withdrawal time for certain livestock. Finally, remember that variation among different control options and different insecticides will help minimize insect resistance and will lead to continued effectiveness in future years.