Have you ever had the following situation happen to you? You go out to feed your horse and notice a fine dust on the outside of the feed bag. You look closer and realize the dust is moving! Yes, you can see all those little bugs bustling about, in search of food and other little bugs to reproduce with. Yuck! Where do they come from? Is the feed safe to give to your horse? Can they harm you?
It turns out that these little critters are grain mites (Acarus siro L). Grain mites are common and exist in all grains, but only thrive and appear when the conditions – temperature and humidity - are just right for reproduction and growth. Their ideal environment is warmer than 77 degrees F, and over 85% humidity. Hence, you would have more problems with them in the warmer months of the year. Temperature changes, condensation, and poor ventilation may produce areas with enough moisture to encourage mite infestation.
If you have infested feed you should not feed it to your horse. These mites can contaminate the feed with allergens and can also transfer nasty germs. Infestation can negatively affect palatability and when animals are fed infested products the results can be decreased intake, inflammation of the intestines, diarrhea, impaired growth and allergic reactions. The good news for you personally is that these mites do not bite humans.
To help reduce your incidence of mite outbreaks:
- Store your feed in a cool, dry place
- Use your oldest feed first
- Keep no more than a two week supply of feed on hand (especially in hot weather) to ensure freshness
- If you store your feed in a container, clean it regularly between fillings to prevent buildup of fines
- Keep your feed area clean and neat
- Air movement, such as from a fan, can help prevent outbreaks
If you do have an outbreak in your feed room, remove affected feed from the room immediately and thoroughly clean the area. Pyrethrin can be applied to the area with a hand held fogging machine or aerosol spray can.