If you know rain is coming and your hay sits in the field at 30-40% moisture, what are your options?

Kevin Shinners suggests baling and wrapping it.

In two years of research, the University of Wisconsin ag engineer baled round and big rectangular bales at 30-40% moisture — even drier in some cases — and wrapped them with an individual or tube wrapper. He wanted to find out if partially field-dried alfalfa could be made into bale silage when it wasn't quite dry enough to make hay.

After five or 12 months in storage, bales “came out looking just great,” says Shinners. “They actually were more attractive than bales made at 50-60% moisture, because at higher moistures they get a slimy, wet outer layer. We never saw that with these dry bales.”

They had an “excellent” silage smell, he adds, even though, in some cases, very little fermentation had taken place.

Dry matter losses during storage were less than 5%, slightly below the levels recorded for silage baled at the normally recommended 50-60% moisture. And the low-moisture bales didn't heat excessively until more than a week after the plastic was removed.

A big advantage he sees for lower-moisture silage is the opportunity to make bigger bales, conserving plastic. Round silage bales usually are no more than 4' in diameter because of their weight.

“At 35% moisture, a 5'-diameter bale actually weighs less than a 4'-diameter bale at 60% moisture,” says Shinners.

However, maintaining the plastic's integrity is more important at lower moisture levels.

“If you cheat on the amount of plastic that you put on, or don't repair holes, you'll run the risk of much greater spoilage because of the low level of fermentation.”

He recommends six to seven layers of plastic for round silage bales; seven to eight layers for rectangular bales.

Shinners was impressed with the tube-line wrapper he used. It's more expensive than the single-bale wrapper, but used 43% less plastic and was 50% more productive.

“It's a one-man operation, too. You drop a bale on and it wraps that bale while you're getting another one. Add that to the reduced film usage and it's a very attractive wrapping option.”

The machine wraps plastic so tight around bales that oxygen can't penetrate down the tube even after it's opened, he adds.

“If bales will be sold or moved before feeding, an individual wrapper might be a better choice,” says Shinners. “No matter what wrapper you use, wrapping low-moisture bales is a viable alternative to rain-damaged hay.”