Agriculture & Natural Resources
Insects in livestock feed and hay Insects show great promise as sustainable food sources for fish, poultry and swine. Some species can efficiently convert organic waste to nutritional supplements while significantly reducing its mass and making it unsuitable as a breeding site for pests.
However, insects and mites in livestock feed are a different matter. Their activities can reduce nutritional quality, acceptability and palatability of feed. In addition, some may serve as hosts for internal parasites. Early recognition of arthropod infestations in feed may prevent establishment of chronic infestations, further spread of the pests and additional feed loss. Often, the best short-term recourse is to destroy infested feed and implement strong sanitation and prevention practices to prevent a recurrence.
Here is a look at some of the insects and a mite that can be found in livestock feed: Rice and granary weevils develop in grain kernels, causing significant problems in farm-stored corn. The grub-like larvae of these insects develop inside kernels. Their feeding and tunneling can result vast amounts of “flour” within the grain mass. The “flour,” composed of insect eggs, waste, fines and shed exoskeletons, may serve as food for other insects, as well as making grain unpalatable.
Mealworms are the wireworm-like larvae of insects known as darkling beetles. These insects can be found in processed feed and cracked grains. The larvae and adults feed on cracked grain kernels, fines and processed feeds. In addition, darkling beetles have been implicated as intermediate hosts of some poultry parasites. The insects live in and around feed rooms, feed bunks and also may be found in stored hay. Both the adults and larvae avoid light and prefer to hide in or under things, so infestations may not be noticed until relatively large numbers of insects are present.
Bran bugs, like mealworm beetles, feed on cracked kernels and fines. Large numbers of dead beetles, their cast larval exoskeletons, and fecal pellets produce “flour” similar to that from weevils. Their metabolic water contributes to grain heating and spoilage. In addition, the beetles produce quinones, that can give feed a pungent odor. Similar in appearance, small red-brown fungus beetles can thrive in moldy grain and feed. Sweet feeds are particularly prone to infestations of these insects and the tiny grain mite.
Grain mites thrive under warm, humid conditions. Infested grain or bags of spoiled feed often have a disagreeable musty odor and are covered with a fine “dust” of living and dead mites. People handling this material may develop dermatitis resulting from mite “bites.” In times past, this condition was called “grocers itch,” a malady suffered by those who regularly handled infested bags of meal or flour.
Scavenger insects can infest silage and spoiled hay. Soldier fly maggots were reported last week from silage in a ground bunker. These fly larvae are common scavengers in wet compost piles and other decaying organic matter. They are an indication of very wet conditions and their activity would liquify the material even further.
Insects are not uncommon in feed. Consumption of a few should not pose a threat to livestock.
If only a relatively small number of beetles is present and the feed or grain is in good condition, it may be practical to feed it. Then, thoroughly clean and treat the storage area and surroundings with an appropriately labeled insecticide before refilling.
However, the responses of animals to different insects can vary. Ingestion of significant numbers could cause gastric distress for some animals. Long-term infestations of large numbers of insects can result in significant loss of feed quality, condition or palatability. The feed odor or taste may make it unacceptable.
Sanitation is the important first step to take when dealing with infestations. Use of a broom and shop-vac can be used to clean cracks and crevices. The goal is to remove accumulations of fines and hidden insects. Infestations can develop from small numbers of insects or mites that are not removed or killed. Appropriately labeled pyrethrins or pyrethroid insecticides can be used after clean-up and before new grain or feed is added. Do not treat feed or grain directly with these products.
For more information on insect identification or management efforts, please contact the Woodford County Extension Service at 873-4601.