Corn silage is the foundation of many winter feeding programs. It provides an excellent source of energy that can reduce the costs of providing energy in a cow’s diet while also serving as a digestible fiber source. The details outlined below can help ensure that high quality feed is preserved.

1. Spend time getting equipment ready before harvest

General maintenance, such as greasing equipment and sharpening knives, needs to be done well in advance of the anticipated chopping date. Advance planning is important for a timely harvest at the proper moisture content.

2. Harvest timing

Harvesting at the correct moisture promotes favorable fermentation in the silage crop and decreases storage losses, so moisture content should be the determining factor for when to harvest. For bunkers, silage should contain between 30% to 35% dry matter (65% to 70% moisture). Upright silos and bags should contain 35% to 40% dry matter (60% to 65% moisture).

3. Correct length of chop:

Silage needs to be chopped finely enough for good packing to quickly eliminate oxygen and establish a good fermentation process. The chop length needs to be long enough to promote cud chewing. Thus, the recommended theoretic length of chop (TLC) is a compromise between these two factors.

Alfalfa haylage or silage = 3/16"

Unprocessed corn silage = 3/8" to 1/2"

Processed (kernel processor) corn silage = 3/4".

4. Adjusting silage choppers with on-line kernel processors

The optimum moisture content of silage harvested with a chopper containing a kernel processor is 62% to 65% (35% to 38% dry matter) to capture additional starch accumulation in the corn kernels. Most of the corn kernels should be pulverized to a similar size. To optimize starch digestion and provide adequate effective fiber, the recommendation is to cut to .75" theoretical length with an initial roller clearance of 0.12". 

5. Keep knives sharp and properly adjusted throughout the filling process

Sharp knives prevent the shredding of silage, resulting in a more uniform chop. This allows for maximum forage compaction, good fermentation and sufficient particle size to prevent health problems in the cow.

6. Fill silos rapidly

Silos should be filled quickly to help eliminate air from the feed. Silos should be filled within a week to prevent dark brown and black bands within the silo. Fill bunkers from the back to the front, adding forage on a wedge and not from the bottom to the top in layers. 

7. Pack, pack, and pack some more

Tightly-packed silage ferments more quickly and contains fewer yeasts and molds than loosely packed silage. Packing silage helps decrease the size of oxygen pockets, resulting in fermentation end products the cow can use better to make milk.

8. Cover silos immediately after filing

Bunkers or piles of silage need to be covered with 6 mil plastic tarps and weighted with tires (tires should touch each other) immediately after filling. The sides of bunkers also should be lined with plastic. Upright silos should be leveled and capped with a silo cap immediately after completion of filling. 

9. Let silage ferment 3 to 4 weeks before feeding

Unfermented feed is higher in fermentable sugars and can cause cows to go off-feed. Gradually transitioning cows over seven to 10 days to newly-fermented silage is recommended. Data suggests that fermentation and maximum percentage of available starch may not be achieved until four months after ensiling.

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