North Dakota growers generally harvested little or no second cuttings and hay yields are down by 30-50%, says J.W. Schroeder, North Dakota State University Extension dairy specialist.

All the more reason producers should cover what forage they do have, he recommends.

Although round bales are designed to shed water, 15-30% of a harvested hay crop can be lost if left outside uncovered. If hay yields are 50% of normal because of the weather, that shortfall can be cut substantially for producers who start covering hay, Schroeder says.

“Even farms that have invested in net-wrapped round bales but leave them outside will find that providing more protection from moisture will save them hay,” he says. “Net wrapping does protect the hay to an extent because it makes the bale surface smoother and denser so it can shed water, but the advantage is not great.”

An average of 15-25% of total dry matter is lost from net-wrapped bales stored outside, according to University of Kentucky trials. Enough rain soaks into the outer layer of hay to cause deterioration, and water running to where bales contact soil is absorbed, also causing spoilage.

Long storage periods and high temperatures during storage also lead to greater losses. High-quality hay such as second- and third-cutting alfalfa is most susceptible. The more digestible the forage for animals, the more digestible it will be for bacteria that cause spoilage, Schroeder says.

The same University of Kentucky study analyzed various forms of hay storage and found that putting the bales under a roof is one of the best options, whether it’s a steel-roof pole barn, older wooden barn or hoop-roofed barn. Total dry-matter losses are typically only 4-7% for hay stored inside and on stone or other means to prevent soil contact.

“The ultimate in hay storage options is building a new structure. Of course, this is a long-term investment, but depending on your needs, it can pay for itself in 10-15 years if hay is stored each year, especially with today’s higher hay prices.”

But plastic coverage is just as good as inside storage, the Kentucky study showed. Renting an in-line bale wrapper can protect dry round bales for less than $10/ton.

Hay stacked on a pad of stone or porous material and covered with plastic tarps can keep losses down to that same level if tarps are secured well enough to stay in place.

Plastic bale sleeves that are slipped over the bale, leaving the ends open, diminish rainfall and soil moisture entry into the bale, resulting in the same 4-7% loss. But labor-intensive bale sleeves work best on smaller volumes of round bales.

Pyramid-stacked uncovered bales, with bottom bales touching the ground, resulted in a 25-35% loss even though half the bales were off the ground, the study showed. Pyramid-stacked bales on stone or a porous pad suffered a 13-17% loss.

Any method of protection is better than leaving the bale exposed to the weather, Schroeder adds.