It’s fly season! Horn flies, stable flies, and face flies are certainly a menace to cattle, but can also have underlying economic impacts if not controlled.

Two types of flies are most prevalent on cattle farms: horn flies and face flies.

Horn flies are around half the size of the average house fly. They have an average life cycle of 10-14 days from egg to adult. These flies suck blood, which can cause irritation and reduce weight gain. Horn flies can also spread infections that can damage udder tissues, affecting milking ability in cows. Roughly 200 flies per animal is when these flies start to cause economic issues. They are usually found around the back, sides, and poll area of cattle.

Face flies are slightly bigger than average house flies, and have a 21 day life cycle. They do not bite, but feed on animal secretions so they are typically found in clusters around the eyes, nose, and mouth. The main issue with face flies is damage to these areas, making them more susceptible to diseases such as pink eye. Face flies are the most difficult to control, because of they are not on the animal very long, and because of the location that they land on the animal.

Another fly found on cattle farms, though slightly less prevalent than those mentioned earlier is the stable fly. These flies are most common on feedlots and dairy farms, as they develop in decaying organic matter like wet hay. These flies may be found in pastures around winter hay feeding sights. These flies are often found around the legs, so they can be harder to control. The best method of control for stable flies is to remove the sources of the decaying organic matter, so the larva has nowhere to develop.

Once the flies are identified, they can be controlled in numerous ways.

Back rubbers and dust bags can be used. These can be purchased ready to use, or can be made for materials you likely already have on the farm. Cattle can “self-apply” with these back rubbers and dust bags, but attention must be paid by the producer to ensure that they have adequate amounts of insecticide to maintain control. These should also be used in conjunction with other fly control methods.

Insecticide ear tags are another effective option for fly control. These are tags similar to identification ear tags, but have been drenched in insecticides. It is important that these tags not be placed too early, as they may be less effective when flies are most active, in mid to late summer. These tags should also be taken out when flies are less active so a resistance to the insecticide is not built up by the flies. It is also important to rotate to tags with differing insecticide classes from year to year. This is another method of decreasing resistance to the insecticide.

Insecticide sprays and pour ons are another method of control. These are a little more difficult, as they last around 21 days and will need to be reapplied throughout the season. This will include bringing cattle to a central location at least once a month to apply the insecticide.

It is important to remember that most of these methods will need to be used in conjunction with other methods to get effective control over all three types of flies mentioned. Once again, the classes of these insecticides need to be varied from year to year to ensure that they remain effective at controlling the flies. A little effort can go a long way when controlling these flies for both the well-being of your animals, and your bottom line!