With the 2017 planting season behind them, most Michigan farmers are now focused on field scouting in the never-ending effort to maximize crop yields. Ironically, many of those same farmers are also settling up their input tab for their 2017 corn crop.
While agronomic management is essential in maximizing yields and return on investment, corn silage producers may miss their maximum ROI—at harvest. Chop length and kernel processing are absolutely essential for corn silage, according to DuPont Pioneer silage experts.
Kernel processing impacts the degree of starch digestion, while setting the theoretical length of chop (TLC) impacts particle length needed for proper rumination. Ensuring good kernel processing starts several weeks prior to harvest.
Make sure the entire chopper is in good condition, especially the chopper knives and the roller mill.
Nicked knives and worn shear bars should be replaced to prevent uneven and shaggy chop lengths. The entire length of the roller mill should be checked for wear on the teeth.
Uneven wear may prevent narrowing of the roller gap. Hours of operation may allow the outer edges of the rollers to touch, leaving an undesirable gap in the middle.
Inspect the roller mill after 400 hours of use. The integrity of the working parts and hours of effective use depend on soil type and other environmental factors. Corn grown on sandy soil, where wind is common, results in more wear and tear, shortening roller mill life. Other factors include roller size and the number of teeth per inch. More aggressive Boosting your corn silage ROI – chop length and kernel processing differential speed options will affect the life of the roller mill.
After inspecting the chopper head and roller mill, check the gap setting between the rollers. It should be 1 to 2 mm to ensure it cracks all the kernels. Check using a dime (1.2 mm wide): If there is excess space between the rolls and the dime, tighten the gap. Next, set the TLC at 3/4 inch, which is longer than the typical 3/8 to 1/2 TLC settings for non-processed corn silage.
Variables Impacting Kernel Processing of Corn Silage
All brands of harvesters (with processors) in good working condition can achieve well-processed corn silage, provided users pay attention to the nature of the crop.
The grain-to-stover ratio of the crop impacts how much grain goes through the roller mill. The higher the grain content, the greater the need for more aggressive processing.
Sometimes that means shortening the TLC to achieve better kernel processing of high starch corn silage.
Harvest moisture also impacts kernel processing. The lower the moisture, the higher the starch content. As you harvest dryer corn, you can decrease the TLC setting. This may lower effective fiber, but it will ensure adequate packing of the dryer forage in the silo.
If feed roll and roller mill adjustments are not producing expected kernel processing results, inspect the differential speed of the roller mill. The upper roller should run faster than the lower roller. Differences of 10 percent to 15 percent are common.
Monitors of Processed Corn Silage
Several forage testing laboratories offer a scientifically validated sieving test known as the Ro-Tap system for quantifying corn silage processing.
The procedure produces the Corn Silage Processing Score (CSPS) values based on percent of starch passing through a 4.75 mm sieve, which represents a percentage of total starch in the sample. Here are CSPS interpretation guidelines for the Ro-Tap system used to measure degree of kernel damage in corn silage:
• Less than 50 percent = inadequate
• 50 percent to 70 percent = normal
• 70 percent = optimum
While the CSPS is an excellent test, the hectic corn silage harvest season doesn’t permit timely CSPS determinations to make sure the harvested crop has proper KPS and TLC values. Growers can inspect loads coming to the storage structure for kernel damage. They can notify the chopper operator if adjustments are required to improve processing.
Processing effectiveness may change from field to field and from day to day, so it is important to monitor kernel processing throughout the entire harvest. Samples should be checked at least once daily and whenever the chopper operator switches to a different field.
The Corn Silage Processing Monitoring Cup is a quick, simple on-farm technique to check degree of processing. DuPont Pioneer forage experts around the world use this method. It involves collecting a 1-liter (32 oz.) cup of chopped forage for field analysis.
Spread the collected sample on clean ground and manually sift through the sample, counting all kernels larger than half a kernel. Kernels need to be completely fractured, not just nicked.
The guideline is no more than two whole or half kernels per sample. While dairy operations and chopper operators may agree on another threshold, the count should never exceed four half-towhole kernels.
The monitoring cup wasn’t developed to quantify the degree of kernel processing as accurately as the laboratory Ro-Tap system. However, it can help silage producers adopt a more aggressive CSPS.
Achieving well-processed, high-starch corn silage is a key to higher-quality corn silage. Operations can reduce levels of supplemental grain in the ration and save costs on rations. It makes good business sense to inspect the kernel processer and chopper settings before harvesting to help ensure their corn silage will help them achieve maximum milk production.