Bugs in a Bag of Horse Feed
Q: When I opened a new bag of horse feed, I found a bunch of little beetlelike creatures in it. I’ve never seen this before, and I wasn’t sure what to do. I returned the feed to the retailer I purchased it from and got a new bag, but now I’m wondering whether I needed to do that? Could I have just kept it and fed it like usual, or could these bugs have hurt my horse? — via email

A: This time of year, owners occasionally find what appear to be beetles in bags of horse feed. These beetles could be bran bugs or weevils, especially if the feed contains whole grains. You can tell weevils apart from other bugs by the shape of their head—adult weevils have elongated heads that form a “snout.” Bran bugs look like weevils, but without the snout.

Weevils live inside and damage whole grain kernels; however, neither they nor other bugs commonly found in grain pose a risk to your horse. That said, such bugs could lower the feed’s nutritional content if they, themselves, are feeding on it. Bran bugs live on broken grain and grain dust.

You might also see meal moths, which tend not to discriminate the same way weevils and beetles do and will attack all forms of grain. The moths lay eggs on the grain’s surface. The eggs then hatch into caterpillars that look like little worms. These larvae create a web over the grain that impacts air movement and results in grain clumps.

While most bugs found in grain originate from within the bag, they can bore into bags from the outside, as well. Clean out all feed bins and storage containers carefully if you’ve had bug-contaminated feed. Weevils can live for up to eight months and venture far from the original food source, so feed room hygiene is important.

Generally when you find bugs inside a feed sack, it is an indicator that the feed has sat for too long and possibly at the wrong temperature. Eggs can be present in feed for some time, and the life cycle length depends on the season (it can take as few as five weeks in the summer and as long as 20 weeks when the weather is cooler). This is likely why we find bugs in feed less commonly in the winter months—the feed is typically consumed before the eggs hatch, so they don’t develop into pupae and adults.

If you find bugs in new bags of grain, check the product’s manufacture date (often found on the paper seam on the bag top or bottom), and consider returning the bag for something manufactured more recently. To prevent the problem from developing later, if possible, buy feed with very recent manufacture dates and make sure you can finish the feed within a month or so of manufacture. If you have access to a freezer, placing bags in it for a couple of days before opening will kill any existing bugs and larvae. However, this is not a realistic solution for textured feeds, and most people do not have access to a large freezer.