When Roger Olson tells how to have “comfortable,” healthy cows, he's talking about tractors and weights, duals, 100' plastic sheets and diligence. He's talking about how silage should be packed and stored to produce consistent, high-quality feed.
Olson, who has part-owned two dairies and is now a dairy consultant from Baldwin, WI, says proper bunker silo management takes technique and a lot of patience.
He admits that bunker silos aren't his chosen method of storage; he likes to pile silage on blacktop or concrete (see accompanying story). But when he bought half ownership of Baldwin Dairy several years ago, he was forced to make do with bunkers.
“I've seen at Baldwin and at other farms, bunkers built in funky shapes around buildings or other objects,” he says. “There are always spots where you can't get silage packed tight and consistently. You've always got more waste.”
Yet Olson was able to produce consistently good forage for his cows and offers the following advice on packing and covering tightly:
Use two heavily weighted tractors for packing, especially if the forage is being harvested with a self-propelled chopper. Olson's goal was to pack each layer twice; once with the blade or push tractor, moving from front to back, then a second time with the pack tractor moving side to side. The pack tractor should almost never be off the pile until the pile is covered, he adds.
“Lots of dairies use one tractor and can get 13- to 14-lb dry matter densities,” Olson points out. Recommended density is 16-17 lbs/cubic foot, but Olson always reached for higher than that. “To get up to that 20-lb range, you really need two tractors.”
Use duals: They cover more surface and are safer than single tires.
Pack feed in thin layers. Olson recommends 6" or less. To do that, you'll need a tractor big enough to keep ahead of the chopper.
Fill using a progressive wedge. It's easier to pack, can be covered in sections and offers better feed consistency at feed-out, he says.
Cover as you go. “Get the plastic on right away, sealing it up as fast as you can.” Covering and sealing should be done in hours, not days, Olson advises. He used 60 × 100' sheets with 12-15" overlap, then sealed edges with ag lime and truck tires placed next to each other.
He also has used a series of small grain ventilation fans to remove oxygen from piles or bunkers.
“They would suck the remaining air out from under the plastic. We would put one every 100', just enough to keep a constant vacuum on the plastic.”
The true test of how well a bunker is managed comes at feed-out. Olson recommends:
Removing at least a 6" layer per day, especially in hot weather.
Shaving silage off the entire face, then mixing it before feeding.
Having no more than a loader bucket of loose silage left at the base of the pile when finished feeding.
Using a face grinder (silage facer) — especially on wide bunkers that need to be emptied in sections.
“What was nice about the face grinder was that we could keep that open side nice and tight. When we came back to feed a second rip, we could take a consistent amount off the face every day and it would still keep oxygen from penetrating into the face of the pile.”
Olson advises bunker managers to keep records of what goes into storage. He always had someone weigh every load and run moisture tests.
“So we knew pretty well how many tons of dry matter and as-fed that we got out of a pile. We also would do dry matter density tests on all our piles and record them.”
For tracking feed-out, he recommends a computerized feed management program such as FeedWatch, E-Z Feed, Feed Supervisor or Feed Tracker.
“We tried to have a system of measure so we could gauge ourselves, get better — and not become complacent,” he reports.
The hardest part to bunker management is having patience and perseverance, Olson says.
“It's really tough to stick to it when you're out there hour after hour, going a quarter mile an hour up and down the pile. The big key is to drive over every spot — twice.”
The Pluses To Piling
One thing Roger Olson was definite about when he built a dairy up in the Red River Valley several years ago was how to store his silage.
“I prefer dome piles, where there's a 3-to-1 slope and a blacktop or concrete slab and plenty of room,” says Olson.
“What I liked about that system was that you could size piles according to the crop coming in. If we had a small pile, we would make it long and narrow. We could size the pile so we could take off 6-12"/day no matter what the volume was. We weren't defined to whatever set of walls we had built several years ago.”
Olson made dome piles on a 320'-long slab. “With bunkers, there are always spots that you can't get packed right consistently. With piles you can pack every inch every time really well,” he adds.