Fly Control in Livestock for Summer

By Ted Wiseman

As summer temperatures rise, so does the pressure from biting and nuisance flies on livestock operations. According to university research, fly infestations cost U.S. producers an estimated $700 million to $1 billion annually in lost performance. With today’s strong livestock markets, minimizing these losses through effective fly control is more important than ever.

Understanding the Impact of Flies on Livestock
Flies reduce productivity by interfering with feeding, causing stress, and transmitting disease. The primary culprits include:

• Horn Flies (Haematobia irritans): These blood-feeding pests remain on the backs of cattle, feeding 20–40 times per day. Economic thresholds are reached at 200 flies per animal. Females lay eggs exclusively in fresh manure, and the life cycle can complete in as little as 10 days under warm conditions.
• Stable Flies (Stomoxys calcitrans): Also blood feeders, stable flies target the legs and bellies of livestock. Their painful bites lead to foot stomping, bunching, and water-seeking behavior. They breed in moist, decaying organic matter especially hay mixed with manure in feedlots or winter-feeding areas.
• Face Flies (Musca autumnalis): Though non-biting, face flies feed on secretions from the eyes, nose, and mouth. Their activity can damage eye tissue and increase the risk of pinkeye. Like horn flies, they lay eggs in fresh manure.