Flies are a major nuisance around the barn. They annoy the horses and if you have ever been bit yourself, you can easily understand why – it hurts! Some horses will even drop weight rapidly during the summer because they spend more time running from the flies than they do grazing. In addition to making the horses miserable, flies can also spread serious diseases like Equine Infectious Anemia. 
 

There is no silver bullet to completely eliminate flies but through a multi-pronged approach, we can decrease fly populations to keep horses and humans alike more comfortable, as well as decrease the risk of disease transmission.

A core feature of a good fly control program is good housekeeping – well barn-keeping. Remove manure and wet bedding from stalls, prevent feed spills and keep water and feed buckets well-scrubbed.

You can also directly address the fly population by disrupting the life cycle of flies through fly parasites, insects that attack the flies during their developmental stages, or feed through fly inhibitor products.

Feed through fly products can be very effective and do not affect the horse. They are excreted in the manure, which is where flies lay their eggs. These products inhibit the eggs from developing into adult flies. If a feed through fly control product interests you, we’d recommend Essential K® with fly control.

For Essential K® with fly control to be effective, all of the horses on the premises need to be on the product concurrently. For maximum effectiveness, begin using feed through fly control 30 days before fly season begins. If starting a feed through fly control product after flies have emerged, some measure of control will be observed within two weeks but six weeks is required to see full efficacy.

If you are in an area with a high density of horses or other livestock, it is important to remember that your fly control program is only as effective as your neighbor’s fly control program. Flies have a remarkable range of flight.

While these approaches help for species of flies that breed in manure and other organic matter, they will not address mosquitoes or horse flies. A comprehensive vaccination schedule, appropriate for the area of the country you live in, combined with elimination of standing water is the best defense against mosquito born diseases.

The above approaches can be combined with fly deterrents such as topical and premise sprays, physical barriers like fly sheets and masks as well as fly traps to diminish the adult fly population.
 

Nicole Rambo, Ph.D.