All About Feed-Through Fly Control for Horses

What is a feed-through fly control?

Similar to many equine supplements, most feed-through fly control products are made to be fed to horses daily in a single scoop of pellets or powder. Feed-through fly control products work by containing an active ingredient that is designed to stop the full life cycle of flies. After a horse eats the product, it is expelled in the horse’s manure. Adult flies land on the manure and lay eggs, which then are unable to develop into adult flies. Since manure is the most common place where flies reproduce around a typical barn, and the typical fly life cycle is 2 weeks long, this can drastically reduce the new fly population.

What is the difference between feed-through fly control products and garlic-based products?

The feed-through fly control products on the market are all meant merely to be passed through the horse, and not absorbed. They are designed to reduce the fly population by breaking their life cycle. Garlic, on the other hand, is used in other products to act as a fly repellant. The horse absorbs the garlic, and many products claim that this repels flies for 24 hours after administration. Garlic will not reduce the fly population like a feed-through fly control product would.

Are feed-through fly control products safe for horses?

Most feed-through fly control products are safe for horses. Many of the feed-through fly control products on the market contain different active ingredients, called Insect Growth Regulators (IGRs). This is what prevents the larvae from developing into adult flies in manure. When selecting a product, look for an IGR that is not an organophosphate. Products that contain an organophosphate can be toxic to horses if given in higher quantities. They can also be toxic to other wildlife. IGRs that are not organophosphates are very safe, and are merely passed through the horse. We recommend feeding MultiFly Feed-Thru Fly Control, which has active ingredient Novaluron and is extremely safe. All feed through fly control products are classified as pesticides by the EPA, and thus have to be registered and have certain label claims.

How do I set my barn up for success when using a feed-through fly control?

These products work best when administered 2 weeks to 1 month before the start of fly season. You want to make sure that all manure on the property is treated, prior to flies beginning to emerge and reproduce. It’s important to clear out untreated manure and transport it off-property before feeding. The product will only show results if fed to all horses on the property. If you have nearby neighbors that are not feeding a feed-through fly control either, ask them if they can start. Flies can travel quite far, and the best results are seen where an area has essentially eliminated where flies can reproduce.

If the product has above 95% efficacy, does that mean that I will have 95% fewer flies?

Efficacy claims are related to the product’s ability to break the fly life cycle in the treated manure. Since there are many external environmental factors that can influence the size of a population of flies, you can expect a dramatic difference, but likely not a complete population elimination. It’s recommended to still use other fly control measures as needed, including fly sprays, fly protective gear, fly traps, etc.
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