Fire ants are very common in many pastures and they can cause some problems in horses and cattle, especially newborn animals. Dr. Kathy Flanders from Auburn University indicates fire ants were accidentally imported into Alabama from South America over 75 years ago and the ants have since spread across the south. Fire ants normally do not cause a lot of problems for adult animals that are mobile, but animals who are down and cannot rise on their own can have major damage inflicted by fire ants. Also, fire ants can cause serious problems in young foals and calves if they are born on a fire ant mound or just lay down near a mound. Most of the time the animals just develop small pustules where they are bitten but some can develop blindness due to damage to the eyes. Some animals can have severe allergic reactions and horses can even founder after a large number of bites.
Treatment of fire ant bites usually involves cortisone to reduce the inflammation as well as pain medication and antihistamines. Sometimes antibiotics are needed due to infection secondary to the skin damage. If an animal’s eyes are affected, contact your vet immediately as I have seen numerous calves go blind because they were not treated soon enough. To control ants in the pasture, Dr. Flanders indicates baits can be applied in a broadcast fashion in the pasture and usually cost $10-$15 per acre. You want to make sure the pesticide you are using is approved for pastures and hay fields, and that the product you choose is approved in the state you are using it in as some states do not allow all products.