By Brad Schick and Ben Beckman
Setting the Stage
Even before storing, producers can give hay a better chance to make it from the field to the cow with as little loss as possible. Baling at correct moisture levels will lead to proper curing without additional heat, mold growth, and dry matter loss. Bales should maintain moisture levels below 20% for this to happen.
Beyond proper moisture, the physical nature of a bale can provide protection against storage loss. Round bales with curved sides and layers running with the curve repel moisture better than square bales. Packing bales densely will also impact the amount of moisture able to enter the bale. While setting balers to a tighter pack and baling at correct moisture levels will impact density, the type of hay put up will be a factor as well. Finer stemmed hay like grass, small grains, or alfalfa can be more densely packed than larger stemmed options like forage sorghum or corn residue.
The materials used to wrap hay will also protect against storage loss. Materials that keep bales held together tightly will be more effective at keeping moisture out. Plastic sleeves and net wrap keep bales together better and may physically block water from entering the bale when compared to similar twine wrapped bales.
Indoor Storage
Storing hay inside is the best option for both types of bales. This is not always possible and is much more cost effective for square bales. Weathering is more detrimental to square bales and more tonnage can be stored in a given area inside. This is no breaking news, but knowing the loss in dry matter and quality can aid in deciding what type of bale to make and what storage method to choose.
Most of the dry matter loss in a bale will occur in the first several months of storage. Even under the best conditions, hay stored inside can lose 2-8% dry matter if stored for extended periods of time. For storage under 9 months, losses should be less than 2%. The dry matter loss for large round bales stored outside can range from 5-25% depending on the climate.
Outdoor Storage
When storing outside, the storage method chosen can reduce loss. This portion will address large round bale storage outside.