That little mouse that lives under your horse’s feed tub and scoots out to grab dropped grain may look cute (to some people anyway), but he is far from a “harmless little creature.” Rodents can spread at least 45 diseases causing serious illness or death in horses and/or humans. If you think most of these diseases are rare, think again.
For example, it’s protozoa from more than just opossums that has been shown to cause EPM (equine protozoal myelitis). Dead rodents, and any places where they were decomposing, can be potent sources of botulinum toxin. Disease also may be spread by biting insects like fleas or ticks that feed on the mice.
In addition to disease, mice can cause serious damage by chewing holes in tack boxes and your tack. They may make nests in stored blankets and shred linings. Rats who burrow and run behind stall walls can make enough noise that they startle horses.
Few barns can be made totally rodent-proof, but several measures can help. Removing overgrown vegetation around the barn discourages rodents, who dislike crossing large open areas.
Check along foundations and doors for mouse-size openings. Mice and rats need only a miniscule opening to squeeze in. A concrete patch (mix found at your lcoal hardware store) should be used to plug openings. Rodents will chew through soft material and add insult to injury by using it for bedding. Follow the same procedure inside the barn.
And, of course:
Store grain in rodent-proof containers and keep trash in closed containers.
Clean up spills or messes the horses leave when eating.
Keep straw or shavings raked away from feed tubs or troughs so spills are easily cleaned. Use a good broom (traditional brooms clean better than push brooms).
Regularly clean hay-and-straw storage areas. Mice love to make nests in the loose material, particularly under pallets. Straw is especially attractive, as there is often enough grain in the straw for good meals.
Cats are your best bet with low-level rodent infestation. Be sure they are well fed at the barn. Cats will “hang out” where they find food.
Owls, hawks and snakes, especially black snakes, are also excellent mousers and ratters. If you have them in your loft, count your blessings (well, for having the birds anyway). You can attract owls by placing nesting boxes. Contact your local agricultural extension office for owl-nest designs.
For heavy infestations (this means you regularly see mice), you may need a professional. A trapping or baiting system may be recommended.
We’re not keen on baiting (poisons) because of the potential of also poisoning cats and dogs that eat or chew on the poisoned rodents. However, if the infestation is so bad that you must use poison, at least remove and restrain domestic animals during baiting and for a week or two after the baiting has stopped.
A section of PVC pipe makes a terrific place to place bait: Rodents are encouraged by the protected and secluded interior. However, remember that mice and rats may also go into nesting areas to die, creating a stench and potentially contaminating hay and straw bales.
Setting traps is effective but only if you place enough — and again keep them away from your pets. Experts recommend 50 to 100 traps be set at the same time for infested barns. Include the entire building — loft, storage areas, tack rooms, etc. The old familiar spring traps are still the best choice. Set them along walls, in corners, between and on top of bales, behind containers. Mice love peanut butter, and it is difficult for them to steal from the traps.
Use caution when removing nests, especially those that have been undisturbed for several months and may harbor large amounts of mouse urine and droppings. Infectious organisms, including the virus responsible for Hanta respiratory illness (see sidebar), can survive even in dried-up nests. The virus is released with dust particles when these sites are disturbed, and this is likely the most prevalent way people are infected. Standard dust masks will not filter out the virus.
The Centers for Disease Control in Atlanta recommends that such areas be thoroughly ventilated and aired out before you enter the building. Old nests, or any area showing telltale signs such as shredded nesting material or rodent droppings, should be thoroughly soaked with a 10% Clorox solution before it is disturbed. Wear gloves and dispose of these materials in plastic bags. If the area is heavily rodent infested, call your Health Department for advice before proceeding.
If you find a dead mouse, think again before tossing it into the woods next door. Experts recommend that dead rodents (or other wild animals) be handled only with gloves and disposed of in sealed plastic bags. If burying them is your only choice, bury them several feet down. Decomposing rodent and other bodies are a serious potential source of botulinum toxin and will contaminate the ground, too.
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Click here to view ”Mice Carry The Deadly Hanta Virus.”