By Scout Nelson
Stable flies have become a major pest of pastured cattle, causing discomfort and weight gain. Cattle show signs such as tail flicking, bunching in corners, leg stomping, and standing in water to avoid bites.
This problem worsened with the shift to large round bales in hay rings, which leave behind spoiled hay mixed with manure and urine—ideal for stable fly larvae. Even grass clippings and poorly managed compost piles can serve as breeding sites.
“An economic injury level (EIL) of five flies per leg has been suggested and is often exceeded in normal pasture conditions.” Research has shown that even fewer flies can reduce weight gain by 0.44 lbs. daily if not managed properly.
Stable flies feed cattle legs and bellies twice a day, rest on shaded structures like windbreaks, and can travel long distances with weather changes. Their full life cycle takes just two to three weeks depending on the temperature and humidity.
Control Methods:
Chemical Sprays: Animal sprays using organophosphates or pyrethroids can be effective but may need repeat applications. Spraying windbreaks and fence lines is another strategy.
Traps: Though more common in confined spaces, pasture trap use is under study. Proper placement and maintenance are key.
Larvicide: Clean up spoiled hay early. If not possible, larvicides like Neporex can be applied to breeding sites.
Early action, proper sanitation, and targeted treatment help reduce stable fly populations and support better cattle health and pasture preservation.
For insecticide details, visit: https://www.veterinaryentomology.org/vetpestx. Always follow label directions.
Photo Credit:gettyimages-pamwalker68
Categories: Nebraska, Livestock