Ag Notes: Avoid feeding animals moldy hay

August 12, 2003|JERRY LITTLE

Because the wet spring and early summer created conditions for mold development in hay, horse owners need to be especially careful not to feed moldy hay to their animals. Moldy hay also reduces the performance of cattle, sheep, and goats so producers should avoid it.

Greater amounts of mold growth occur when hay is baled above the safe moisture level of 18 percent for large, round bales and 20 percent for small, square bales. Mycotoxins, poisons produced by these molds, can cause problems when moldy hay is fed to animals.

There are hundreds of different mycotoxins which are diverse in their chemistry and effects on animals.

Horses shouldn't be fed moldy or dusty hay even when the amount of mold or dust appears to be minor.

Any hay (alfalfa, timothy, clover and fescue) containing mold can inflame a horse's respiratory tract and impair its breathing ability.

Many horses develop permanent lung damage after consuming moldy or dusty hay. This chronic lung damage, often called "heaves," affects the horses' ability to breathe normally during exercises. In severe cases, heaves impair the horse's ability to breathe normally even at rest.


Mold can have other detrimental effects on horses such as causing digestive upsets and contributing to colic. Although red clover has a good nutrient profile, it sometimes is affected by a mold that causes horses to slobber. This slobbering doesn't appear to harm the horse, but most handlers find it offensive.

Cattle, sheep, and goats don't like moldy hay so they eat less of it. This results in reduced performance from less intake of lower quality hay.

Some hay with a significant amount of mold can be used in cattle rations because cattle are less sensitive to the mold spores. However, feeding cattle too much moldy hay causes increased disease incidences and reduced production efficiency.

When fed too much moldy hay, dairy cattle don't give as much milk and their immune systems and reproduction can be affected. In addition, dairy producers can experience huge economic losses from milk contamination.

Beef cattle frequently consume large, round bales of hay with some mold present and rarely have any problems. However, abnormally moldy hay can lead to decreased intake, resulting in reduced performance such as a lower rate of gain. If you suspect that hay is excessively moldy, you might want to have samples sent to a diagnostic laboratory to be tested for mycotoxins.

Sheep and goats will avoid moldy hay if at all possible; animals will pick around moldy hay, or not eat it at all. Thus it's not a very efficient feed source and is best avoided.

When selecting hay for pleasure or farm animals, be concerned about the overall quality. Generally, large round bales have more mold than the small square ones.

In addition to cleanliness, nutrient value is another important consideration.

Legumes (alfalfa and red clover) typically have a much high protein and calcium content that grass hays, such as timothy, orchardgrass and bermudagrass. Legumes also may be higher in energy and total digestible nutrients.

When the price per ton among various hays is similar, alfalfa usually is the best value because it has more nutrients and tends to be more palatable than other types so animals usually will waste less.

The best way to evaluate the nutrient value of hay is to have a chemical analysis performed. Use forage core samples from at least 20 bales to get the most accurate analysis. Typically the analysis will determine moisture, crude protein, neutral and acid detergent fiber levels (that help determine energy content), calcium and phosphorous.

You also need to match the type of hay to each animal's nutrient needs.

Duck hunting

A big-city, Indianapolis lawyer went duck hunting in rural Kentucky. He shot and dropped a bird, but it fell into a farmer's field on the other side of a fence.

As the lawyer climbed over the fence, an elderly farmer drove up on his tractor and asked him what he was doing.

The litigator responded, "I shot a duck and it fell in this field, and now I'm going in to retrieve it."

The older farmer replied. "This is my property, and you are not coming over here." The indignant lawyer said, "I am one of the best trial attorneys in Indiana and, if you don't let me get that duck, I'll sue you and take everything you own."

The older farmer smiled and said, "Apparently, you don't know how we do things in Kentucky. We settle small disagreements like this with the Kentucky Three-Kick Rule.

"The lawyer asked, "What is the Kentucky Three-Kick Rule?"

The Farmer replied. "Well, first I kick you three times and then you kick me three times, and so on, back and forth, until someone gives up."

The attorney quickly thought about the proposed contest and decided that he could easily take the old codger. He agreed to abide by the local custom.

The old farmer slowly climbed down from the tractor and walked up to the city feller. His first kick planted the toe of his heavy work boot into the lawyer's groin and dropped him to his knees. His second kick nearly wiped the man's nose off his face. The barrister was flat on his belly when the farmer's third kick to a kidney nearly caused him to give up.

The lawyer summoned every bit of his will and managed to get to his feet and said, "Okay, you old coot now it's my turn."

The old farmer smiled and said, "Naw, I give up. You can have the duck."

Jerry Little is Boyle County extension agent for agriculture and natural resources.


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