With corn silage harvesting well under way, Karla Hernandez, South Dakota State University Extension forages field specialist, shares some tips to help get the best out of this crop.
For starters, Hernandez says corn for silage should be harvested between 60 to 70 percent moisture.
"This moisture range is the most ideal for optimum fermentation and a rapid drop in pH to preserve the feed value of the crop," she says.
More tips Hernandez shares include:
• Maturity: Keep a close eye on corn maturity once it has dented. Corn can rapidly mature or dry down as a result of weather and moisture conditions.
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• Milk line: A very basic estimate of whole plant moisture for harvest can be made using the kernel milk line. The kernel milk line is the dividing line between sugars in the maturing kernel and starch deposited.
"Most producers in South Dakota will use the one-third milk line as the point to start checking whole plant moisture to determine the optimum timing for silage harvest," Hernandez says. "On the other hand, maximizing the nutritional quality of corn silage and minimizing shrink losses are two main factors to take into consideration when feeding livestock."
Hernandez says harvesting corn silage too early at less than 30 percent dry matter (DM) will result in lower starch concentration in the silage. But, mature corn silage with more than 38 percent DM could also have less nutritional value because of lower fiber and starch digestibility.
• Moisture content: Moisture content can be estimated in chopped silage using the grab test method. Other testing procedures that involve drying and weighing the samples will yield more precise results.
• Increase dry matter yield: If you have immature corn to harvest, allow the crop to mature as long as possible to increase dry matter yield per acre.
• Inoculant: Adding a research proven bacterial inoculant to corn silage can reduce dry matter losses and increase silage digestibility.
Factors affecting
shrink losses
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Minimizing shrink is an important factor in silage economics, Hernandez says. Some of the factors that affect shrink losses include:
• Type of structure: Bunkers usually have greater shrink compared with other types of storage structures.
• Chop length: Finely chopped forages can be packed more effectively, but chopping too finely can result in a lack of effective fiber in the diet. Cutting lengths of approximately half to three-fourths range because of effective fiber should be satisfactory. Making sure knives are sharp also will improve the pack density.
• Rate of filling: Slow filling will reduce the rate of fermentation, so pH stays higher longer. Some of the problems with shrink losses are the air trapped inside the silage. This will promote yeasts and mold causing serious problems to the final product.
• Packing capacity: Not having enough packing equipment at the pile to keep up with the capacity of today's silage choppers can be a challenge. Adding a second tractor might be necessary for to make sure the silage can be packed thoroughly.
• Covering the silage: Covering a bunker with plastic as soon as possible after filling is the best choice to reduce shrink and spoilage losses.
