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Stable Flies

(Stomoxys calcitrans)

A light grey/brown colored fly on a white background.


Courtesy of R. Grantham, OSU Department of Entomology and Plant Pathology


Stable flies are similar to house flies in size, they have a protruding piercing/sucking mouthpart.  Both males and females feed on blood.  

Stable flies feed on the legs of livestock (and even humans) with their head upward. They cause a very painful bite.





Life Cycle

Infographic of the six stages of a fly's life cycle

The life cycle of the stable fly is completed in 21 days, with the fly’s life span ranging from 20-30 days. The females must intake a blood meal before they can reproduce and lay eggs. One stable fly female can lay 200-400 eggs at a time. The eggs and larvae need a moist organic matter to grow in.  This could be soiled straw or other bedding, manure piles, spilled feed, or even old round bale feeding sites. Really anything with a concrete interface could serve as a suitable habitat. The adults will spend time off the host, resting around calf hutches, pens, feed areas, drover alleys, water tanks, and feed troughs.


Photo courtesy of Cornell University College of Agriculture and Life Sciences.



Damage Done

A close-up of a flies on a red cows legs/hooves.

Stable flies have a very painful bite.  Affected animals will be regularly stomping their legs and bunching together. That means the animals will spend less time eating a drinking. Stable flies can cause the most damage in feedlots and dairies. The flies can decrease weight gain by .48 pounds per day. This can cause beef cattle to be on feed for an extra 30 days depending on the situation. Stable fly populations as low as 5 stable flies per foreleg can cause economic losses in a feedlot situation.


Photo courtesy of Progressive Cattle.


How to Control

As with the majority of flies the first step is sanitation. Remove soiled bedding, old hay, split feed, clean up feed areas, and manure from drover’s allies at least once a week to limit and control stable fly habitat. Parasitic wasps, insecticide baits, sticky traps, premise sprays, and some feed additives can help manage a stable fly population.

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