Flies are just as annoying to cows as they are to people. But two types of flies cause actual discomfort for cows – stable and biting flies. Both of these flies bite and draw blood. Here are some tips for recognizing and controlling them.

Watch for flies that hang around a cow’s legs. If cows are bunching together in a pen and stomping or kicking, stable flies are most likely to blame.

Stable flies develop in spoiled vegetation. A silage bunker, unused hay ring feeder or bedded pack that uses straw are likely stable fly breeding areas. Also know these flies can travel up to a mile. So even if your place is clean, your neighbor could be breeding them for you.

Biting horn flies are typically a problem for pasture cows. These flies can develop in an undisturbed cow pie. Watch for a cloud of flies on a cow’s back that will get off when disturbed but then get right back on.

Examine potential biting flies closely. Both stable flies and biting flies have what looks like a pin needle for a mouth. Look for them on vertical surfaces like a wall or barn support beam. After biting, stable flies like to digest a meal resting on these surfaces. PD

Bill Clymer