Editor's Note: The following article was written by Jim Isleib, crop production educator with Michigan State University Extension.
Farmers are talking about wrapping large bale dry hay to be stored outside with a couple layers of plastic to protect it from the weather – and some of them are doing it. The increasing cost of hay production and resulting value of quality hay may provide a good reason for spending extra time and money to reduce storage loss. Wrapping dry hay allows farmers to protect feed from the weather without building more structures.
If the hay is in string-tied bales and to be stored outside, then a couple turns of plastic may be an economic advantage, as long as the gain due to reduced storage losses outweighs the loss in increased expense. If they are net-wrapped bales, and you know they will be stored outside, then putting extra net wrap on while baling may be as effective, economically speaking. Dry round bales wrapped with an in-line wrapper with plastic wraps of 6 to 8 inches overlap can still result in a layer of decomposed hay on the outside of the bale.
The basic idea is to keep rain and melting snow from entering the bale and ground moisture from wicking up through the bottom. But is two layers really enough? Some farmers believe that more layers, up to six, are well worth the extra cost. A thicker barrier is more dependable than a thin one, but more costly. If new to this approach, it may be wise to experiment with different wrapping thickness on your own farm. Starting out with more wrap, and leaving a few bales with less for comparison, could help you decide for yourself.
Another alternative is the use of round bale "sleeves." These plastic covers are open on both ends of the bale and are meant to protect from precipitation above and wicking from below. If handled carefully, they can be reused for two years.
For a comparison of large round bale storage, read University of Wisconsin Team Forage member Craig Saxe's article "Big Bale Storage Losses; how different options stack up."
Source: MSU Extension News