Such an easy supply of organic matter means that flies can populate quickly and easily, meaning a good fly control plan is essential to success. In this case, it requires both sanitation on the farm and control with insecticides or other live fly control measures.
“Flies irritate cattle, disrupt normal behaviors, and are a vector for disease transmission,” explained Emily Bourdeau in a recent Miner Institute Farm Report. “Excessive fly populations can contribute to cows bunching to relieve fly pressure. This results in reduced lying times, which has a domino effect: decreased milk production and feed efficiency, increased lameness, and, during the summer months, increased heat stress.”
With these challenges in mind, Miner Institute’s Bourdeau suggested first considering how to break the reproductive cycle by keeping the farm as clean as possible. Removing the preferred fly egg-laying location impedes the pests.
“Frequently removing manure from pens with an automated scraper, skid steer, or shovel, and scraping areas where manure might be building up will help remove fly breeding environments,” detailed Bourdeau.
While cleanliness goes a long way, it’s best to pair sanitation with some type of fly control measure. Bourdeau recommended insecticides that target different life cycles of the fly.
“To target flies in the early stages of life, eggs and larvae, you can apply residual larvicides to places where flies lay their eggs. To target adult flies, residual adulticides can be applied, and they are often cheaper than larvicides.”
Adulticides are familiar to most dairies. They are most effective when applied between 65°F and 90°F. Effective insecticides include baits, sprays, and topical treatments. Predatory insects can be similarly effective.
“Flies are a nuisance to us and our animals, but with proactive consistent management strategies, we can minimize their impact,” Bourdeau concluded.
The author is a dairy farmer in Kansas and a former associate editor at Hoard’s Dairyman. Raised on a 150-cow dairy near Valley Center, Kansas, Maggie graduated from Kansas State University with degrees in agricultural communications and animal sciences.
