Dry hay provides for best feeding quality
Make it right, store it right
By Denise Schwab
Hay is not an inexpensive feed to raise, harvest, store and feed, so why would anyone be complacent about storage losses? Hay, especially large round bales of hay, are often stored outside, yet outside storage can easily result in 20-30% or more loss.
A meta-analysis of hay storage studies by Dr. William Edwards in 2017 showed an average loss of 27% for round hay bales stored outside on bare ground with a range of 5 to 61%, while bales stored off the ground to prevent moisture absorbing into the bottom of the bale average only 22%, with a range of 3-46%. Hay stored off the ground with a cover, or stored in a barn resulted in only 5% storage loss.
Some factors that affect storage include harvest moisture, forage type, bale shape and density, and binding, all practices related to making it right! The common industry standard for dry hay is 80-85% dry matter (15-20% moisture) but this varies slightly based on bale type.
More tightly compacted bales require a higher dry matter concentration since the bales don’t ‘breathe’ as well to let minor moisture dissipate. A good thumb rule is greater than 82% dry matter for large round bales, greater than 80% for small square bales, and greater than 84% for large square bales.
Bale binding also makes a difference on storage losses. A 2018 study by Reiter from Minnesota showed that twine bound bales stored outside on wood pallets resulted in 5.3% storage losses while net wrapped bales had 4.9% losses and B-wrap bales had nearly 0% storage losses.
Many may not remember much of what we learned in geometry, but basic geometry defines why we see such large losses in bales stored outside, especially large round bales. Producers often say they only see spoilage or forage quality losses in the outer 2-3” of the bale, however on a 5 foot bale, that 2-3” contains a quarter of the bale volume. On 6 foot bales, 2-3” is 15% of the bale volume. So, what looks like a small amount of spoilage or loss adds up quickly.
A joint South Dakota and Wisconsin study used moisture maps to demonstrate what happens with moisture movement within bales during storage in various storage conditions. In this study they purchased round bales and stored them in various configurations for 12 months. All bales were stored outside on the ground with no covers, and this was a wetter than normal year. Dr. Kevin Shinners from the University of Wisconsin created moisture maps of the bales 8” from the flat side of bales to demonstrate moisture movement within bales. The blue shows higher moisture levels and the orange is dryer hay.
All these photos are taken from Round Bale Storage Conservation, SDSU, and can be viewed here. As you can see in Figure A, even hay stored in a barn will wick some moisture up from the ground, but observe as the moisture increases from either wicking from the ground or rainfall seeping into the bales. Remember all these stack configurations were uncovered. Covers over stacks will drastically reduce the impact of moisture compared to these images.
Not all producers can afford hay storage buildings, and storing all hay for a large herd in a building can become impractical, but a few simple practices can help reduce weathering and moisture losses. The first and maybe easiest is to store hay off the ground to prevent the wicking of moisture up into the bale. This could be creating a base of rock or even pallets, tires, telephone poles, or anything to stop contact of the bale to the ground.
The second step is to reduce moisture from entering the top of the bale, by using either a tarp or plastic cover. Plastic bale wraps tend to be more expensive but result in storage losses equivalent to inside barn storage. Totally anaerobic storage is not needed for dry hay, like it is for baleage because ensiling is not needed.
What can you afford to pay for these storage practices? It depends on the cost of hay. For example, let’s assume bale wrapping will reduce storage losses from 25% to 5%, or a 20% reduction. If hay costs $100/ton, and we reduce losses 20% that means we could spend $20/ton for wrapping or storage improvements.
Another way to look at it is if hay costs $100/ton out of the field and you currently use 150 tons per year, your total cost is $15,000. If you reduced storage losses by 20% you would only need 120 tons, so your cost would be $12,000 per year, saving $3000 per year. Three thousand per year won’t build a hay storage barn, but it will help cover the costs of wrapping or purchasing a base to store hay on.
For many producers, storing all hay inside is not practical, but there is still value in improving storage capabilities a little at a time. To capture the most value, prioritize storing the highest quality hay in the best storage scenarios, and reserve that hay for feeding animals with higher nutrient requirements like late-gestating and early lactating females, and young calves.
After the time, expense and effort to make the best quality hay possible, store it in a manner to get the most and highest quality product into your cattle.
Schwab is the Iowa Beef Center interim director and an Extension beef specialist with Iowa State University.
