They don’t see eye to eye on everything it takes to successfully dry down and harvest quality hay and haylage. But University of Wisconsin’s Dan Undersander and Kevin Shinners agree that conditioning and wide swaths are essential.

“Wide swaths aren’t anything new,” says Shinners, an ag engineer. “Adam and Eve knew that, when they put their fig leaves in a tight pile, they didn’t dry out as fast as if they laid them out wide.”

“When we started coming out with conditioners, people thought that, because we were conditioning, we didn’t need to wide swath anymore,” adds Extension forage specialist Undersander. “But it’s really important to recognize that the two are totally different, and we need both. Conditioning helps the stems dry; a wide swath helps leaves dry.”

At seminars and other informational meetings, this Midwestern duo is working to reduce hay-harvest misinformation and mismanagement. Here are some common points, supported by university research, they’ve been making.

First, mow alfalfa at a 2-4” cutting height and grasses or alfalfa-grass mixes at 3-4” tall. With the exception of ryegrasses and bluegrasses, grasses store energy higher up on stems than do legumes, so need the added inch for adequate regrowth.

“Then we have to do a really good job of conditioning the crop,” Shinners says. Conditioning will physically break stems and the waxy layer covering them, allowing water to move and plants to dry.

To cut and condition alfalfa or alfalfa-grass mixes as dry hay, Midwesterners should use intermeshing rubber rolls to crush plant stems. In the West, with its more abrasive soils that can rapidly wear rubber rolls, steel rolls should be used to crimp or bend hay stems.

“Our research has shown that you don’t see a lot of difference in the amount of conditioning that you get and the subsequent drying rate – as long as you do a good job of setting both rolls up,” he says in comparing roll types. However, rubber rolls have more conditioning area and often dry slightly faster than steel rolls.

“If you’re growing grass, you may want to consider using an impeller conditioner,” which is designed specifically for the crop. Roll conditioners have difficulty conditioning fine grass stems, he says.

Shinners is often asked if conditioning is important when making haylage. Fresh-cut forage, he answers, holds about 75% moisture and haylage is put up at 55-62%, according to testing lab averages. “To move from 75% to 60% moisture you have to lose 900 gallons of water per acre. You need to condition well in order to get that water to leave that plant.”

But, growers also inquire, wouldn’t unconditioned haylage offer a longer window for chopping? “That’s absolutely true,” Shinners agrees, “because unconditioned forage dries slower than conditioned forage. But this is a practice that may put your forage at risk.

“I often think conditioning is like an insurance policy. Some years and some cuttings, it may not make much difference. But it’s the cutting where you get your material put up and your neighbor doesn’t – and then it rains for the next week – that pays to condition.”

Undersander thinks mowing without conditioning may be an option for growers who only make haylage. “It’s cheaper and takes less energy. But you do lose zero to four hours drying time for haylage. Sometimes it’s significant. Sometimes it’s not.”

In Wisconsin, Canadian and European studies comparing mowers to mower-conditioners, conditioned swaths always dried faster, Shinners says. In fact, conditioning increases drying rate at any swath width, Undersander adds.

“We did a study where we laid out conditioned and unconditioned swaths that were 90% of the cut width, 60% of the cut width and 30% of cut width, or in other words, a narrow windrow,” Shinners says. “All of the material that was conditioned – even the material laid in a narrow windrow – dried to chopping moisture sooner than that laid out at 90% of the cut width and not conditioned. Conditioned forage will be ready to chop sooner than unconditioned, and conditioning is absolutely needed for making dry hay. Unconditioned forage for dry hay will take too long to dry and place the crop at greater risk.”

Swaths are considered wide if laid at 60% or more of cutting width, the experts say.

“What we’ve seen with wide swaths is faster drying all the time and higher forage quality about 70% of the time,” Undersander says. “We don’t always get higher quality, but we always get faster drying.”

He conducted 13 trials on drying rate, comparing swath widths. “With a wide swath (cut in the morning), 80% of the time we were able to chop it that evening. If somebody wants it dry, like to 50%, then you will have to wait until the next day. But if you’re willing to make baleage, or chop your silage at 65%, you can cut in the morning and pretty well get it there by nightfall or by suppertime.”

An argument Undersander hears against width swaths is that they force growers to drive on crop. “So we’re suggesting a 70% swath where you can drive on it with one wheel but not the other. Yes, driving on it slows drying rate, but it’s the lesser of two evils – it’s less damage than making a narrow windrow.”

In his trials, using the same mower-conditioner, the forage specialist adjusted the baffles on back for different swath widths. Swaths at 70% of cutting width, mowed at 9 or 10 a.m. for haylage, were at 60% and ready for chopping by 5 p.m. In other trials, the crop dried to 60% by 2 p.m.

“On average, wider swaths are higher in quality,” he says. “But we really only saw quality differences in 10 out of 14 trials.”

Choose mowing equipment carefully, as some will offer swath widths at 80% of cut area while others only go to 40%, Undersander cautions.

“We are seeing a lot of new high-capacity mowing equipment – triple and double mowing units,” Shinners says, “where you can get a pretty good percent of the cut width laid down as a swath. The problem is the center mower. Because you have to get material placed between the tires so it won’t get run over, that center windrow tends to be quite a bit narrower than its mates on the outside and doesn’t dry as well.”

Additional Wisconsin data show that conditioned alfalfa tedded at full width got to chopping moisture the fastest. But tedding adds a pass, additional compaction and more opportunities to knock leaves off as well as lays the crop where mergers and rakes can run over it, Shinners says.

If growers use front-mounted rakes or the new self-propelled merger just on the market (see Product Preview, page 37), they can avoid running over the crop.

Shinners built his own experimental machine, mounting a hydraulically operated tedder on the back of a windrower. “It worked nicely,” he says. “We found that it really paid to ted it immediately – it gives a faster drying rate.”

Undersander doesn’t recommend tedding alfalfa because of the potential to knock leaves off.

Rake or merge haylage just ahead of the chopper, Undersander advises. “If you’re making hay, our recommendation is to mow one morning, rake the next and because you had a day’s drying, you get a fluffier windrow.

“The common complaint from commercial hay growers is, ‘I need to put up green hay.’ But hay does not bleach in the first 24 hours. As the plant starts to dry, then the bleaching occurs,” he says.

For more information, see Best Practices to Hasten Field Drying of Grasses and Alfalfa, UW Extension bulletin A3927.