Flies can be more than a pest for cattle producers because the insects can cause cattle to lose weight.
That's why University of Nebraska-Lincoln Extension expert Dave Boxier says ranchers and feedlots should try to control flies.
Boxier says he's expecting a fairly normal fly population this year in Nebraska.
One kind of fly that causes problems is the horn fly. Groups of flies gather around cattle and feed off their blood around the horns and neck.
Stable flies also feed on cattle blood, but they attack the animal's legs.
Another pest is called the face fly, which can irritate the eyes of cattle and cause blindness.
Boxier says there are different ways to control each problem fly, so cattle producers need to figure out what they're dealing with.