The biggest fly threat and dollar loss comes from the horn flies, followed by face fly, horse fly and the stable fly. Each of these flies irritate cattle in different ways such as sucking blood, transmitting disease and being a nuisance when cattle are grazing.

“The stable fly probably gets the least attention. However, they do suck blood, and when present in even small numbers, as few as five, they seem to drive cattle crazy,” said Cole.

A University of Nebraska study measured nearly a one-half pound a day decline in steer weight gains when stable flies were not controlled.

The Nebraska trial used a 3X per week insecticidal spray treatment to control the stable flies. Cole says this frequency of treatment would not be practical under most pasture management systems.

“The usually reliable horn fly control methods do not work on stable flies. Dust bags, ear tags and pour-ons do not reach the lower portion of the cattle’s body where the stable flies feed. The oral larvacides do not control their breeding habits, as they use old manure, straw and bedding for those purposes,” said Cole.

Kansas State studies have shown that an important egg laying area for stable flies is around big bale rings. Moving the rings regularly and not overfeeding can reduce the hay-manure build-up where the stable flies multiply.

“Observe your cattle regularly, and if stable flies are suspected, take steps to reduce your cattle’s discomfort and improve your profit margin,” said Cole.

For more information, contact any of the MU Extension livestock specialists in southwest Missouri: Eldon Cole in Mt. Vernon, (417) 466-3102, Andy McCorkill in Dallas County at (417) 345-7551 or Logan Wallace in Howell County at (417) 256-2391. 

—From University of Missouri Extension Southwest Regional News Service