Producers use a bit of art when they should use science in determining round hay bale prices, agree Extension experts from the University of Wisconsin (UW) and University of Georgia (UGA).

Fair market value is most easily determined if bales are sold on a per-ton basis, says Mike Rankin, UW crops and soils agent from Fond du Lac County. Pricing according to bale weight takes the variability of bale size and density out of the equation, adds Dennis Hancock, UGA forage specialist.

“But if there’s no way of weighing bales, people still purchase by the bale,” says Rankin with a sigh.

The problem with that is, he points out, “you can have a bale that weighs 600 lbs or one that weighs 1,200 lbs. You need to know the weight of the bale, and it’s hard to estimate that.”

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Sometimes growers determine bale weight by looking at their baler manuals, and if the guides specify that 1,000-lb bales will be produced, that’s what some growers will relay to buyers, says Hancock.

“But there’s a tremendous amount of variability from one bale to the next, from one crop to the next and from one producer to the next as to how dense those bales are going to be.”

To offer producers a bale-weight guideline, Hancock put together a table. It shows common bale widths and heights and estimates the pounds of dry matter in those bales at different bale densities.

People tend to overestimate bale density, so should assume the bale’s weight is 10% less than indicated in the table, he says.

Bale density is determined by several factors, including the type of crop being baled. “Alfalfa will create a more dry-matter-dense bale than will bermudagrass or straw.

“The second factor would be the operation of the baler. The baler has certain constraints and pressures that it’s applying to the bale to form it, particularly belt-type balers.”

Other factors have to do with the baler operator – how fast he runs the baler through the field – and the thickness of the windrow. If baling a thick windrow, the baler draws in more material at a time and doesn’t pack it as tightly, producing lighter bales than if baling thin windrows that form denser layers in the bale.

Before determining round bale prices, producers should identify the quality of the forage they’re dealing with. That means getting forage tests from labs preferably accredited by the National Forage Testing Association, Hancock says.

“If you’re dealing with a variety of species, whether they be bermudagrass or fescue or alfalfa or timothy, it’s best to use RFQ – relative forage quality – for a rough determination” of quality.

RFQ, rather than relative feed value, allows farmers to compare quality among species in a standardized way.

How round bales are stored is another critical quality and price consideration, says Rankin.

“We still see a lot of round bales that get dumped outside, so you want to know how they are stored. You probably need to think about adjusting that price down if there’s a loss in quality around the outside of bales,” he says. Consider, too, if growers worked to preserve quality by wrapping or covering the bales, he says.

Hancock estimates that round bales left in fields will average a 4” loss around the outside of a 5’-wide bale. That translates to 20-25% spoilage per bale.

“If you store your hay out there like that, you’re paying for a barn whether you want to or not, because you’ve lost every fourth bale,” he says.

Round bales should be bought “on the basis of quality and pounds, not on color and looks and the number of bales,” Hancock says.