If you’re cutting alfalfa haylage in wide swaths, you don’t need to condition it. And cutting in wide swaths – covering 70% of a machine’s cut width – is the best way to dry haylage fast and at a high quality, said Dan Undersander, University of Wisconsin extension forage specialist.

“Frankly, a lot of us had come to believe that if we conditioned, we didn’t need to make full swaths like we did in the past. But we cannot expect conditioning to substitute for a wide swath.”

Compared to standard swaths, which are only around 30% of cut width, wide swaths expose more of a windrow to sunlight. And sunlight keeps leaf guard cells open, allowing 20-30% of the water in the leaves to escape.

“Conditioning,” Undersander said, “does not affect water loss from the leaves. We want to lose water from the leaves and from the stems. All the machinery and everything we talk about is focused on losing water from the stems.”

Cutting in wide swaths also slows respiration – the breakdown of starches and sugars, he said. “If we get a plant dried down to about 60%, it doesn’t respire much anymore. So the faster we get that done, the fewer starches and sugars we lose. Wide swathing is the only way to do it.”

In field trials, Undersander said, about a day in drying was saved by going to wide swaths. “For silage, we’re generally able to put it up within four to eight hours on the first day – we can get down to 65% moisture. For haying, we’re talking about the second day. With a narrow swath and conditioned hay, it took a day longer to get to the same moisture content.”

Some growers have been concerned that driving over a wide swath will increase soil or ash content in the forage. Research, however, has shown wide-swathed haylage has less ash in it than haylage from narrow windrows, he said. Wide-swathed hay stays on top of stubble; narrow windrows tend to sag to the ground and, when picked up, add soil to the forage. Driving on windrows can be minimized, he pointed out, by driving one wheel on the area between swaths and one near the middle of the swath where the amount of cut forage is less.

Mowing without conditioning also uses less energy and is faster. Undersander has seen one operator mowing at 30 mph. “He had a pretty smooth field, too,” he said.

Undersander acknowledged that many growers will still need conditioners because they harvest hay as well as haylage. “But a conditioner is not necessary for alfalfa silage.”

He recommended, when shopping for a new mowing machine, to look at those with the widest swath widths. “Conditioners have basically stayed the same width as cutterbars have gotten wider. That means we’re channeling more hay through a smaller opening. Some mowers will only make a swath that will cover 40% of the cut area. But you can buy some machines that will give you swaths that will cover 60-70% of cut width.”

Read more coverage from the Alfalfa Symposium...