Livestock Entomology

Stable Flies

Stable flies (Stomoxys calcitrans)



 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.


stable fly life cycle.jpg


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.


stable fly on cow legs.jpg


Damage Done: 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.


How to Control: As with the majority of flies the first step is sanitation. Remove soiled bedding, old hay, spilt 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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