Over the past several years, it has become clear that there are benefits to feeding processed corn silage. With these nutritional benefits documented, UW Ag Engineer, Kevin Shinners, has done several research trials to help characterize crop physical properties of various plant maturity stages and measure the impact of machine variables such as theoretical length of cut (TLC), roll speed differential, and roll clearance. He also addressed the issue of power requirements and harvester capacities when processing whole-plant corn silage. Here are some of the results and conclusions from these studies:

• Unprocessed whole-plant corn silage cut at 3 /8 inch TLC is a common harvesting strategy. Compared to this practice, whole-plant com silage cut at 3/4 inch TLC and processed with rolls on the forage harvester had:

• Within the limits tested the clearance between the processing rolls appeared to have greater effect on the level of kernel processing than roll speed differential. It is obvious from the data that even a change of a few thousandths of an inch in roll clearance can greatly affect the physical properties of the crop material.

• Independent of clearance or speed ratio, the level of processing of whole-plant corn silage appeared to increase as the plant matured. As maturity increased, the kernels and cobs were observed to be larger and, therefore, might have been more likely to be damaged by the processing rolls.

• The data showed that when properly set-up, both self-propelled and pull-type harvesters did an excellent job of processing whole-plant corn silage. The self-propelled harvester may be more sensitive to changes in roll clearance because of its tremendous harvesting rate and subsequent thickness of material flowing through the crop processor.

• With a very mature, black layer crop, the 1/2, 1/4 and 1 inch TLC all produced a similar level of kernel processing. However, the longer TLC produced a crop that may be more beneficial to ruminant health because of greater whole-plant particle size and greater quantity of coarse fiber.

• The processed treatments at 3/4 inch TLC and 1/8 or 3/16 inch roll clearance required similar power to the control unprocessed treatment at 3/8 inch TLC. It appears that the physical property benefits of processing whole-plant corn silage can be achieved with no loss of harvesting rate or additional power requirements

• Based on crop physical properties, harvester power requirements and dairy cattle lactation performance, recommended settings when harvesting whole-plant corn silage would be 3/4 inch TLC and 1/16 to 1/8 inch (1 to 3 millimeters) processing roll clearance.

• Crop conditions and machine set-up can change throughout the harvesting day, so you should check the level of processing on every load and adjust the roll clearance to deliver the level of processing you need.