The suggested roll settings on shredlage units are only starting points.
Corn shredlage has piqued the interest of many dairy producers and nutritionists due to the benefits of more physically effective fiber (peNDF) and highly processed kernels.
Our group of dairy nutritionists has been quietly supportive, but cautious given the limited research on its benefits. We learned more about shredlage along with some of our clients in eastern Wisconsin this fall.
My associate, Matt Waldron, helped adjust choppers fitted with shredder heads by shaking hundreds of samples for multiple farms and custom harvesters through a four box Penn State forage separator. He quickly realized that the suggested roll settings on shredlage units were only starting points. There were too many unprocessed kernels and long sortable pieces of stover.
Separated shredlage fractions from the four screens of a Penn State shaker box.
During the course of evaluating the silage through the shaker box, we developed our own set of guidelines for what looked like good feed.
Top Box: Look for ripped or shredded material that will pack well and reduce sorting. Obviously sortable (by the cow) particles indicate settings need to be adjusted. We recommend 15 – 25% in this box (low grain or drought stressed corn may be higher).
Second box: When machines were set properly, kernels on this screen were shattered. They were typically about the size of a half kernel, but were either empty kernels or severely "tortured" where the starch should be more quickly available. We recommend about 55-60% in this box.
Third box: This is where the small pieces of kernels and kernel contents ended up. We recommend 22-27% in this box. The fourth box contained less than 3%.
In our opinion, over 25% retention in the top box may create packing problems, especially in drier silage. It may also lead to sorting in the finished product. Careful monitoring through the entire harvest is imperative as field conditions change.
We worked with Claas, Krohn and John Deere units during this harvest. Although we observed some very obvious differences between brands, we expect the technology gap between brands will close very quickly.
We found that it took most of a day on some farms to dial in a given chopper, so it’s important to stay on top of it to avoid putting up too many mistakes. Given the variability, a minimum of 4 truckloads and three to four samples per truck should be shaken before making chopper adjustments.
Corn silage is packed at an eastern Wisconsin dairy recently.
With the exception for one machine, we harvested at maximum theoretical length of cut (26-32 mm) and adjusted particle length by tightening the rolls. The maximum roll gap out of all units was 1.9 mm.
Tightening the rolls to the "sweet spot" often resulted in choppers having to run slightly slower than normal (4-5 mph). But we did not find that it was necessary to bog down the machines in order to get good feed.
In the end, after shaking hundreds of samples and a mild case of tendonitis, our dairies were pleased that Matt was there to monitor the harvest. We have a favorable view of shredlage and are confident that well adjusted shredlage units will result in superior kernel processing as well as more peNDF across farms and field conditions compared to traditional corn silage.
You can read more about shredlage here and here.