Moldy hay. No matter how hard you tried, last summer you baled some hay that was a little too wet, and now you have some mold. So how do you go about safely feeding this moldy hay?
Feeding moldy hay to livestock is a tough decision. Although all hay contains some mold, when mold becomes easily noticeable, the decision becomes important.
Usually, mold makes hay less palatable, which can result in lower intake or animals refusing to eat the hay. Other problems from mold can occur because of mycotoxins produced by certain mold fungi. This is a big part of the decision problem because not all molds produce mycotoxins, and the amount produced by those that do is unpredictable.
Direct negative effects of moldy hay are difficult to document. Horses may be more sensitive to mold than most livestock. For instance, mold spores often contribute to respiratory and digestive problems such as colic or heaves in horses.
Cattle apparently are less affected by mold, but certain molds can cause mycotic abortions or aspergillosis. People, too, can be affected by mold spores. Mold can cause a condition called farmer's lung, where the fungus grows in lung tissue. So, try to avoid breathing in many of these spores.
The best course of action often is to minimize feeding moldy hay to more sensitive animals, such as horses or pregnant cows. This may require a keen eye or sensitive nose when selecting hay to feed each day. Mixing moldy hay with other feedstuffs sometimes can dilute problems, but be careful that you don't make your animals sick by tricking them into eating bad hay that they normally would refuse.
Moldy hay is a difficult problem to deal with. Common sense and good observations often are your best decision aids.
Anderson is a Nebraska Extension forage specialist.