Mike Rankin
During my high school years, finding new boundaries was just a part of the maturation process. With age comes a legal driver’s license and the ability to create mischief in ways never before imagined. Put four or five like-minded high school boys together and . . . well . . . the ability to wreak havoc in a small community is limitless.

My dad knew this, so he sat me down one day and offered this sage advice: “Mike, nothing good happens after midnight.” Although he wasn’t mandating I be home by midnight, it was strongly suggested and encouraged.

There are other situations in life where nothing good happens. It’s certainly that case on a farm or ranch. Lose the “hot” in hot wire — nothing good usually happens. Try to interseed alfalfa into an existing, thinning alfalfa stand — nothing good usually happens. Put hay into storage — nothing good usually happens.

But wait . . . what can go wrong with hay in storage? Isn’t the battle usually getting it there?

Although that’s true, we also know for certain that forage quality and dry matter retention during storage never improves. In fact, it can decline substantially, depending on the initial baling moisture and storage conditions.

Although it’s always a good idea to test forage as it goes into storage, it’s perhaps an even better strategy to test hay as it comes out of storage as well. Just how much forage quality will change from pre- to post-storage largely depends on the moisture content at baling and if the hay is stored indoors or outdoors. Further, if it is outdoors, has some effort been made to protect it from the weather elements?

Across the U.S., weather conditions and bale types vary dramatically. In the arid West, where large square bales are baled at moisture levels of 12% or lower, it’s not uncommon for bales to be stored outdoors in stacks.

According to Glenn Shewmaker, professor emeritus and longtime extension forage specialist at the University of Idaho, even this dry Western hay is subject to minor heating, and dry matter losses in the range of 5% are common over a six-month storage period.

When hay is either baled at higher moistures or wetted during storage, forage quality losses from respiration and heating begin to mount. Respiration results in lower forage quality by reducing the amount of nonfiber carbohydrates (sugars and starch). This raises the percentage of fiber fractions and may actually cause crude protein levels to rise.

Excessive heating causes usable protein to decline as amino acids and sugars bind to form insoluble nitrogen compounds. This is often referred to as caramelized forage, which offers zero feeding value.

Even with hay baled at a moisture level of 8% and tarped in stacks, Shewmaker has documented acid detergent fiber (ADF) levels rising by 5.3 percentage units and relative forage quality (RFQ) dipping by 10 points.

Finally, Shewmaker cautions about dry hay touching damp soil or concrete surfaces. Dry hay easily wicks moisture, and the bottom bales can account for up to 50% of the total dry matter loss in storage.

Whatever hay-storing challenges exist in the West, they can be multiplied by a factor of 10 for the Midwest and East, where hay is generally baled wetter, experiences more precipitation events during storage, and typically exists in more humid conditions.

In the eastern U.S., large and small square bales are rarely seen stacked outdoors, covered or not. The same cannot be said for large round bales, and this is where double-digit dry matter and forage quality losses occur for all of the same reasons they do in the West.

Although barn storage is often a worthwhile economic investment, the popularity of outdoor storage can’t be ignored. Extensive research has been done to determine how outdoor storage dry matter and forage quality losses can be minimized simply by choosing a well-drained location and storing bales in the proper orientation.

Nothing good happens in hay storage, but we can always do a better job of minimizing our losses. Let’s make that a goal as we head into the 2021 harvest season.

This article appeared in the March 2021 issue of Hay & Forage Grower on page 6.

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