Jaylor: 5 Most Common Questions About Corn Silage

The 5 Most Common Questions About Corn Silage



1. At What Stage Should We Chop?

Kernel milkline has traditionally been used as an indicator of when to harvest corn for

silage.

The best milk production results when corn is chopped at around the one-half milk line

stage of maturity.


Harvest at 35% Dry Matter


It now appears that the best use of milkline is as an indicator of when to start checking

whole-plant moisture.

When most of the kernels are dented and the milkline is visible, it is time to chop some

corn to measure moisture content.

Actual whole-plant moisture should be your trigger for when to start chopping.

2. At What Moisture Should We Harvest?

Determining the moisture content of corn silage is essential in making the decision to

when to harvest.

Both the microwave oven and Koster tester methods are acceptable; however, I prefer the Koster tester, as it is easier and safer.

Alternatively, the “grab test” to determine the DM content of forages can be used.


“Grab Test” to Determine the DMContent of Forages

Description of Forage Ball Approximate DM Content

Holds its shape but has considerable free juice

Less than 25%

Holds its shape, hand is moist but there is little free juice

25-30%

Expands slowly, with nofree juice

30-40%

Springs out and falls apart rapidly More than 40%


Cows will milk best on corn silage at 65 to 70% whole-plant moisture.

This range in moisture also works well for achieving good preservation in horizontal

silos.


Harvesting whole-plant corn with more than 70% moisture increases seepage losses and

creates more acidity which can lower dry matter intake, and reduces dry matter yield

per acre.

If corn silage that is chopped at less than 60% moisture it will need to be either chopped fine or processed to minimize losses in starch digestion and milk production.


3. At What Length Should We Chop?

The general recommendation for corn silage harvested with a conventional harvester (i.e.

without a processor) is 3/8-inch (9.5 mm) theoretical length cut (TCL).

This recommendation may vary between ¼-

inch (6.35 mm) and ½ inch (12.7 mm) TCL, depending upon whole-plant and kernel moisture, hybrid, and forage harvester.


Evaluate % coarse particles and degree of kernel and cob processing to determine the

proper TCL setting for your chopper.

Corn silage that is harvested past one-half milkline stage of maturity or with less than 65% whole-plant moisture may need to be

chopped at ¼-inch TCL.


It may be possible to chop corn silage that is harvested at an immature or wet stage and hybrids that exhibit

soft kernel texture at ½ (12.7 mm) TCL.

The recommended chop length for corn silage harvested with a harvester fitted with a processor is

3/4-inch (19.1 mm) TCL.

Processed corn silage that is harvested at black-layer or with about 60% whole-plant moisture may need to

be chopped at ½-inch (12.7 mm) TCL.

4. How Can We Tell if the Crop Processor is Set Properly?

Mechanical processing of whole plant corn has been an accepted method to improve the quality of corn

silage.

Whole plant processing crushes the entire plant through rollers and can be accomplished in the field during harvesting, at the silo but prior to storage, or

after ensiling and just prior to feeding.

Processing corn silage improves starch and fiber digestion and allows for good packing in silos even

with a longer length of particle chop.


The recommended roll clearance ranges from 1/16 to 1/8 inch (1 to 3 millimeters) (or follow manufacturer’s

guidelines for specific machines).

Care should be taken to monitor the effectiveness of the processing.

When large amounts of acreage require harvesting, there may be a tendency to open the rollers more

than what is recommended in order to speed up the harvest and to reduce wear on equipment.


You can determine clearance using feeler gauges.

If you do not have feeler gauges, lay the blade of your pocketknife flat between the rolls and

adjust the clearance until the rolls tighten against the blade.


Chop some corn, shake out the material using a shaker box, and visually inspect each screen for degree of

kernel and cob processing.

We like to see all kernels broken (adequate processing is occurring if more than 90-95% of the kernels are crushed or cracked) . Pieces of cob, if discernible, should be no

larger than the end of your little finger.


If kernel and cob breakage is not complete, tighten the rolls until kernel damage is complete, or consider

reducing your TLC.

This may be necessary for processed corn silage that is harvested at black-layer maturity or with less than

60% whole-plant moisture.

Improvements in milk production appear to be about 1 kg/h/day.


A common observation by producers switching to processed corn silage is the reduction in cobs in the feed bunk and a reduction in kernels in the manure.

Caution should be taken when switching cows from non-processed corn silage to processed corn silage.

With processed corn silage harvested at an immature or wet stage that tends to mush, you can set roll

clearance to 1/8 inch (3 millimeters).

5. At What Height Should We Chop?

Silage dry matter yield is reduced about 15% as

the chopper head is raised from 6 to 18 inches (15 cm to 46 cm).

But estimated milk produced per ton of silage goes up because the more fibrous and less digestible portion of the plant material is left

in the field.

5. At What Height Should We Chop?

Switching to 18 inches (46 cm) of stubble from 6 results in estimated milk per acre being

reduced only about 3%.

Determine your needs for tonnage vs. quality to determine the best cutting height.

Bottom Line

Harvesting corn at the right moisture and particle size is crucial.

Plant moisture, rather than kernel milkline, should determine when you start to chop.

Watch particle size and kernel and cob breakage to make sure the processor is

doing its job.

Use additives properly, pack well and cover securely to minimize storage losses.

Bottom Line

Education

Jaylor: 5 Most Common Questions About Corn Silage