Dairy producers need to do a number of things just right to put the best feed into, and take the best feed out of, their bunker silos. Two Wisconsin dairy families work hard to do just that.
“You have to have a passion for it, and you really have to sweat the details,” says Paul Natzke, who heads up feed operations at his family's 1,200-cow Wayside Dairy near Greenleaf. Other members of the family management team include his uncle, Dan Natzke, and cousin, Jeremy Natzke.
Over the course of a typical year, the Natzkes put nearly 30,000 tons of homegrown haylage and corn silage into 10 bunkers. The smallest bunker measures 150 × 50'; the largest is 120 × 200'.
For both haylage and corn silage, the Natzkes emphasize the importance of applying an inoculant during chopping. Their goals are to limit spoilage, extend the life of feed in the bunker and prevent secondary fermentation.
“It basically stabilizes the feed,” Natzke says. “When you put a more consistent feed in front of the cows, they eat more and have fewer health problems.
“We see it (using the inoculant) as an insurance policy,” he adds. “We put a lot of time and energy into our chopping. Spending another 50-60¢/ton on an inoculant isn't going to kill us.”
For packing, he utilizes two tractors, one with a blade to push material onto the pile, the second for packing only. Combined weight of the tractors is 80,000 lbs.
“Our goal with the blade tractor is to keep the depth of the feed layer in the pile for the packing tractor at no more than 6”,” he says. “The important thing is to keep the loads from coming in too fast. If you start putting a load on top of a load, it works against you.”
Natzke strives to achieve a packing density of 18 lbs/cu ft or more. “The industry standard is somewhere around 15 lbs/cu ft,” he says. “If you work at it,you can exceed that.”
Doing a good job of covering and sealing the bunker is another component of Natzke's bunker management game plan. His goal is to start covering within an hour of when he finishes packing. With a crew of 10 or so high school kids, he can usually finish the job in two to three hours.
The importance of getting abunker or silage pile covered and sealed as soon as possible after filling can't be overemphasized, says Keith Bolsen, professor emeritus of silage management at Kansas State University. His research shows that delaying covering for a week can nearly double dry matter losses.
“On most dairies, getting the pile or bunker covered within 12-24 hours after filling is probably a realistic target,” says Bolsen.
As with packing, Natzke emphasizes thoroughness when covering the bunker.
“As we're getting started, we have a person go over the top of the pile with a pitchfork to level out the high spots,” he says. “We want that surface to be as nice and flat and clean as we can get it.”
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Three years ago, the Natzkes began including Silostop in their covering routine. It's a clear, plastic sheeting material that helps keep air from coming into contact with stored feed.
“We were having some problems with mold 6-8” from the top a few years ago,” Natzke explains. “We were throwing away a lot of feed. Now we're holding our shrink to around 10% or less.”
He covers the Silostop with a layer of black and white 5-mil plastic to block ultraviolet light. To hold the plastic in place, he uses 3' × 6” bags filled with pea gravel along the bunker walls and tire sidewalls in the center.
After the bunkers are covered, Natzke makes it a point to check the plastic on all of them at least once a month. “If I find a tear or a hole, I'll tape it right away,” he says.
For feed-out, Natzke utilizes a silage facer.
“We usually deface the front of the pile for about an hour before we feed,” he says. “You get the drier material from the top blending in with the wetter material from the bottom. Whenever you can keep the dry matter consistent, the cows are going to benefit.”
The Schmitz family — Ray and Sylvia and their son and daughter-in-law, Matt and Heather — also emphasizes attention to detailin managing the bunkers for its 600-cow Valley View Dairy near Richland Center.
“When we first switched over to bunkers (from upright storage), we thought maybe we could be a little more lax,” says Ray Schmitz. “We found out in a hurry that's not the case. With bunkers you really have to stay on top of management.”
Like the Natzkes, the Schmitzes apply inoculant when harvesting both haylage and corn silage. Schmitz figures its cost at 60¢/ton for haylage and 57¢/ton for corn silage. They also emphasize proper packing (two tractors) and use a facer when it's time to feed out. The dairy has bunker storage capacity of 9,200 tons of corn silage and 1,500 tons of haylage on a dry matter basis.
Schmitz believes that good bunker management starts with putting forages into the bunker at a consistent moisture content. He looks to harvest haylage crops at 60-62% moisture; corn silage at 67-72% moisture.
“If you get it into the bunker at the right moisture, you're going to do a lot better job of packing,” he points out. “The more packing we do, the more we realize how important it is.”
For the corn silage crop, the producers start monitoring moisture levels at tasseling.
“We figure we're about 45 days away from harvest at that point,”he says. “When we're about a week or so away from harvest, we'll do a chipper test (a service provided by their local co-op). Once we get started chopping, we want to get the whole crop into the bunker in three or four days to ensure consistency. Fewer changes in moisture content and digestibility are very important for milk production.”
For covering and sealing,the Schmitzes use a wrap-around approach. They start by placing a sheet of white and black plastic on the floor of the bunker, roughly 4' out from each sidewall. Then they move up the bunker walls with the plastic. When packing is complete, they overlap the two plastic sheets and cover with tires.
“We've done it this way for about three years,” says Schmitz. “We used to just go over the top with the plastic. But we'd get a valley in one or two spots, and the water would manage to get down under the plastic and ruin some of the feed. This works a lot better.”
Like all top-flight dairy managers, the Schmitz family is continuously assessing management for areas where they might improve. Currently, their milk production average is around 28,000 lbs on 3X milking.
“We've heard some real good things about Silostop and will probably give it a try soon,” he reports. “We certainly don't think we have all the answers when it comes to managing bunkers. We're willing to share ideas on what's worked for us and we're more than willing to listen to others on what is working for them.”