|Long, narrow bags filled with pea gravel hold down the edges of a plastic feed covering. The bags' weight helps keep out oxygen.
So, you spent months growing your forages, then made it through the hectic days of harvest, chopping and packing. Ready to lose 20% or more of all your hard work?
That's the amount of shrink loss that far too many dairy bunker silos and drive-over piles see each year, says Keith Bolsen, professor emeritus at Kansas State University.
Bolsen spent much of his 32-year career researching forage and silage management. And he continues to study improvements in feed storage even in his retirement. With the hope they'll provide "every opportunity for single-digit shrink," Bolsen recommends these practices:
Density matters. Start with achieving a higher silage dry matter density. Aim for a minimum target of 15 lb. to 16 lb. of dry matter per cubic foot. "Density and shrink are inversely related," Bolsen says.
Perfect pitch. Shape all surfaces so water drains off the bunker or pile. The back, front and side should not exceed a 3-to-1 slope. Seal the forage surface immediately after filling is finished.
Double the covering. A sheet of oxygen barrier film, such as Silostop, plus a sheet of plastic or tarpaulin are preferred to a single sheet of plastic.
Go beyond. Overlap the sheets that cover the forage surface by a minimum of 6'. Arrange plastic sheets so runoff water doesn't come into contact with silage. Sheets should reach 6' off the forage surface around the perimeter of a drive-over pile.
Anchor down. Put uniform weight on the sheets over the entire surface of a bunker or pile. Double the weight placed on the overlapping sheets. Bolsen prefers sandbags filled with gravel to anchor overlapping sheets. Gravel-filled bags provide a heavy, uniform weight at the interface of the sheets and bunker silo wall. A 6" to 12" layer of sand, soil or sandbags can effectively anchor sheets around the perimeter of drive-over piles.
Bolsen isn't a fan of using full-casing discarded tires to anchor bunker or pile covers. "These waste tires are cumbersome to handle and messy," he says. "Standing water in them can also help spread the West Nile virus."
Bias-ply truck sidewall disks, with or without a lacework of holes, are the most common alternative to full-casing tires. You can stack sidewall disks and sandbags. If placed on pallets, they can be moved easily and lifted to the top of the bunker wall when the silo is being sealed. They can also be lifted to the top of the feed-out face when the cover is removed.
Small holes, big problems. Prevent damage to the sheet or film during the entire storage period. Mow the area surrounding a bunker or pile. Put up temporary fencing as a safeguard against domesticated and wild animals. Store waste polyethylene and cover-weighting materials so they don't harbor mice and other vermin.
|California dairy consultant Ron Kuber checks packing density, slope and silage quality at this pile on a dairy near Visalia, Calif.
"Regular inspection and repair is recommended because extensive spoilage can develop quickly if air and water penetrate the silage mass," Bolsen says.
- May 2009