Feeding Moldy Hay
All hay has some level of mold in it but it’s not always apparent. However, when the mold is noticeable, and you see dust from the spores, your decision of how -or if - to feed it to livestock becomes very important.
Dan Buskirk is an associate professor and beef Extension specialist at Michigan State University. He says the best decision is not to feed it, but that’s usually not a practical option. Another course of action is to feed it to less-sensitive animals that have a lower risk of negative health effects.
"If we feed that to non-pregnant growing cattle, for example, we may not see much of an effect of some mold except for some decrease in feed intake and possibly decrease in performance," says Buskirk. "But, I get a little paranoid when we have a large quantity of moldy feed that we’re planning to feed to pregnant cows because we can cause abortions in those cows and that’s something we certainly want to avoid."
Another option is to dilute the moldy hay with other feedstuffs.
"How much do I need to dilute it? The answer is dilute it as much as I possibly can," he says. "Think of it as diluting my risk of something bad happening and causing ill-effects to the cows, causing abortion, or something like that."
Buskirk says you should completely avoid feeding hay with moldy sweet clover in it. When sweet clover is damaged it can produce an anti-clotting agent that causes serious issues for cattle such as hemorrhaging and respiratory stress.