Their life cycle is about three weeks in summer and longer in cooler weather. Females deposit 400 or more eggs during their life. Stable fly development may occur in any wet, decaying organic matter, but primarily occurs in animal waste mixed with soil, straw, hay, silage or haylage and grain. Thus, the feedlot or dairy often provides ideal fly breeding media. Stable flies probably overwinter in breeding areas below the frost-line as slowly developing larvae.
Stable flies feed on most species of domestic livestock, but are major pests of cattle and horses.
They penetrate the animal's skin with their piercing mouthpart and feed on blood. They primarily feed on the front legs, causing cattle to bunch in a circle with each animal trying to protect its front legs. The economic losses for feeder cattle, even at low stable fly population levels, are dramatic. They range from 0.1 pound to 0.48 pound per head per day decreased weight gain, depending on fly numbers. These losses are particularly acute when heat stress also occurs.