After doubling chopping capacity and nearly maxing out packing-tractor weights, the men at Kutz Dairy, Jefferson, WI, have been looking for other tools to increase silage density.

They found two pull-behind silage packers. One is the Impact Silage Packer, which has been on the market for a year and a half and distributed in the U.S. by Agromatic, Inc., Fond du Lac, WI.

The machine (originally called Spanjer, below, at right) comes in several sizes with a bracket on top to hold chained-on concrete blocks weighing about 2,500 lbs each. Its stainless steel wheels are concrete-filled.

The other, called the Faster Packer, is manufactured by Linway Manufacturing, Fenwick, MI. This unit utilizes seven heavy-duty railroad wheels, each weighing 850-880 lbs.

“We have a lot of weight added to our tractors already that can only cover the tires – the center is open,” says Aaron Kutz. He, his brother, Allan; and dad, Ron, milk 1,550 cows, raise 1,400 acres of corn and alfalfa and harvest 15,000 tons of corn silage. The packers “pack a little harder and tighter than just tires on your tractor.”

“We’re covering more area and applying a higher pressure,” adds Allan. “We think it’s a higher pressure – we don’t have any proof that it actually works that way. It just makes logical sense to us.”

They paid about $10,000 for each machine. Linway’s Faster Packer weighs 10,000 lbs on its own; the nine-roller Impact Silage Packer weighs 10,850 lbs once concrete blocks, which they bought separately, are added.

The Kutz brothers especially liked the durability of the Faster Packer.

Brian Holmes hasn’t seen any research on machines of this type. “Theoretically, it’s possible you can get enough weight and distribute it over an area and come out

with okay densities,” the University of Wisconsin ag engineer concedes. But he remains skeptical that the machines will be economically viable.

“Silage density appears to be a function of axle load instead of pressure on the surface,” he says. “The axle load of a 40,000-lb tractor is 20,000 lbs. A 10,000-lb packing machine has only half this packing capacity. Adding this same 10,000 lbs to the front and rear of a 40,000-lb tractor increases its axle weight to 25,000 lbs.”

Rich Muck is curious about the concept of adding packing weight behind a tractor. He’s a USDA-ARS scientist at the U.S. Dairy Forage Research Center, Madison, WI.

“I am interested to see if it would do some good. It looks like it does a nice job of leveling things off. It should add to the packing process. But I don’t have any data to be able to say anything one way or another,” he says.

He’s also heard that a sheepsfoot roller, usually used in construction, has been successful in packing silage. “I think a lot of these concepts could possibly have a positive effect.”

Around 40 Impact machines have been sold to 250-cow to 2,000-cow dairies and custom harvesters in the U.S. and Canada, says Jeff Liner, Agromatic sales and marketing manager.

“They’re looking for extra weight to go with the tractors, but want that extra weight be put in a smaller area,” he says. “We feel we can get about 50 psi per roller. We want to drive that weight down to pack the silage in, and the raking action helps level the pile.”

The Impact comes in five sizes, including a five-roller at 3,300 lbs, a seven-roller at 4,500 lbs, a nine-roller at 5,850 lbs, an 11-roller at 7,150 lbs and a 13-roller at 8,450 lbs. Concrete blocks can be bought with the model or made locally to save on freight costs, Liner says.

Densities have been measured after using the machine, he says. “But we’ve had difficulty comparing one pile to the next and then also comparing one year to the next because of all the variables involved with the dry matter content, the times that you drive over the pile – a lot of the management factors that go into packing a silage pile. But we definitely do see a benefit in the numbers that we’ve seen.”

The Faster Packer (at left) was a collaboration of Linway Manufacturing’s Linus Martin and Don Themm. Themm has designed dairies for his company, Don Themm Enterprises, as well as others.

“There were a lot of bunker silos out there and a lot of bad feed in them. And it’s strictly due to packing,” Themm says. As forage harvesters have increased in capacity, silage density has decreased because producers aren’t taking the time to pack well, he adds.

“So I had my ideas, what I wanted to accomplish. Linus took my ideas and made them better,” Themm says.

Martin says all four of the packing models he’s built are either sold or spoken for. He attaches recycled train wheels to a low-hanging frame to keep the point of gravity low. “That’s for safety reasons; all our weight is at the silage level,” Themm says.

The machine’s Michigan distributor is Sam Straub, Straub Agri Sales, Rodney, MI, who measured the density of a 2010 corn silage pile after a 9,000-lb seven-wheel packer was used behind a Cat Challenger tractor. The corn was cut about 1” long at 58% moisture with a kernel processor. Density was recorded at 24.4 lbs dry matter per cubic foot, he says, cautioning that it was just one test.

Straub recommends the machine be used with a tractor at about 250 hp or more.

For more on the Impact Silage Packer, call 800-800-5824 or visit www.agromatic.net. For details on the Faster Packer, call Themm at 800-808-4366 or Martin at 989-261-3285.