Question
A fellow boarder was feeding her horse ears of field corn one evening. The kernels were hard and a deep golden color. I asked her if this was from this year’s planting, and she said it was from an old corncrib that was on a relative’s farm. Is this a safe practice?
Answer
Feeding corn to the horse is not an issue, as it is often an ingredient in high-quality, well-formulated feeds. The concern involves where the corn was stored and for what duration it was there.
Corncribs are relics on most farms these days. Usually fashioned from wood, they were once commonplace on farms. The walls of the corncribs were typically not entire, purposely left partially open, as by wire or alternating slats, to allow air to circulate throughout. While ventilating the corncribs was essential for keeping the corn dry, the openness often allowed rodents and other vermin to gain access.
If ear corn becomes wet during storage in a corncrib, there is a chance that mold will develop. Unlike cattle, horses are extremely sensitive to mold. This is evident in the difference in hay that can be fed to the two species; generally cattle can tolerate more dust and mold than horses can.
If a horse consumes corn contaminated with toxins produced by Fusarium spp., it might be at risk for moldy corn poisoning, also known as equine leukoencephalomalacia. This disease progresses quickly in most animals with death occurring within a few days. Clinical signs of the disease include anorexia, lethargy, and a roster of neurological deficits: staggering, circling, head-pressing, and inability to swallow.
Though this is not a common disease, it is a deadly one and there have been numerous outbreaks recorded throughout the United States. Cases seem to pop up in late fall through early spring and are especially prevalent when a dry growing season is followed by a rainy fall.
While contaminated kernels might be off-colored, there is no definitive way to tell if corn is infected with the disease-causing fungus by visual inspection. Corn screenings, a by-product of corn handling and processing that contain, among other things, whole and partial kernels of corn, are another likely source of contamination.
The best way to prevent a case of moldy corn poisoning is to provide horses with a professionally formulated and manufactured concentrate that is appropriate for age and lifestyle. When fed by itself as a concentrate, corn does not supply adequate nutrients for optimal health.
The temptation to give horses treats is a great one, but I’d stick with more traditional ones: apples, carrots, or an occasional alfalfa cube.
