Corn Silage: Part 2 Equipment Settings and Safety

As you’re gearing up (pun intended!) for corn silage harvest, keep these recommendations and tips in mind to have a productive and safe harvest season. In the second segment of the corn silage podcast series, UW-Extension specialists discuss tips to get the most out of your crop this year and how you can do that safely.


Liz Binversie, Brown County UW-Extension Agriculture Educator


Matt Lippert, Wood County UW-Extension Agriculture Agent

Joe Lauer, PhD, Corn Agronomist, UW-Madison/UW-Extension

Randy Shaver, PhD, Dairy Nutrition Specialist, UW-Madison/UW-Extension

John Shutske, PhD, Agricultural Engineering Specialist, UW-Madison/UW-Extension


Time: 10:39 minutes


Liz Binversie: Greetings, I’m Liz Binversie, Brown County UW-Extension Agriculture Educator, and I will be your moderator for today. On the panel is Matt Lippert, Agriculture Agent for Wood County UW-Extension; Joe Lauer, Corn Agronomist for UW-Madison and UW-Extension; Randy Shaver, Dairy Nutrition Specialist for UW-Madison and UW-Extension; and John Shutske, Agricultural Engineering Specialist for UW-Madison and UW-Extension. Harvesting at the right time is key, but it’s also equally important to use the proper settings on harvesting equipment to make sure you get the most out of this year’s crop. Matt, what should producers keep in mind as they get their equipment ready for corn silage harvest?

Matt Lippert: Thanks, Liz. We have a lot of capacity, horse power, and a lot of efficiency of the equipment as it moves through the field. It’s one of the more impressive operations we have on our farms today. If it’s not operating correctly, we can produce a lot of less than optimal feed very quickly. This equipment needs to be monitored continuously to produce a consistent and high quality product. We’ll be discussing some of the tools on hand that we can use to help make these on-the-go assessments. Corn silage is considered a forage but is really two feedstuffs being harvested and stored together, often in nearly equal proportions. We have grain and fodder. The grain—even though not harvested at full-maturity, as for dry grain—still relies on processing and storage time allows fermented silage to optimize starch availability. The rest of the plant needs to be uniformly cut to optimize packing in the bunker and for adequate fermentation and to maintain adequate effective fiber in the diet and to minimize sorting and feed waste. Many forage harvesters today utilize two steps to fully process the silage. Knives are used as in haylage to establish a theoretical length of cut (TLC). In addition, processors may roll or shred silage. The entire plant goes through the processor but it is especially beneficial for breaking up cobs and providing adequate processing of corn kernels without creating loss of TLC or the fodder fraction of the feed. Joe Lauer, I left out many details, so I hope you can fill in the spaces that I left.

Joe Lauer: Thank you, Matt. One of the things that I wanted to touch on was the things that can still be done in the field with harvesting corn silage. One of the most simple things that can be done—and it’s really a function of how much forage was able to be harvested over the season up to the time of corn silage harvest. One of the things that can be done is to adjust the cutting height of that corn silage out there. For every foot that’s raised, basically you lose about 15% of your forage tonnage—your yield. However, the milk per ton increases as that cutter bar is raised as well because you’re leaving the lowest quality plant part out in the field—the lower part of the stem. That’s where all the nitrates accumulate and where most of the moisture’s at. Even though you lower your yield, your forage quality goes up and your overall milk per acre is not affected all that much. It’s really lowered relatively minimally—only about 4% or so from a normal cutting height of about 6 inches. You do end up with lower yields but you do have a better quality product that’s out there. How high should you go? Well you certainly want to get the ear and you want to get the grain into that corn silage because that’s where a lot of the energy of corn silage is located. Another advantage for raising that cutter bar and leaving the poorest quality plant part out in the field is you can increase your residue cover on the soil and that can possibly lower soil erosion come next spring. Again, a relatively small change will affect your yield but it can also improve the quality of that corn silage that’s out there as well as adjust the moisture of that product going into the bunker. Randy, did you have any other thoughts about cutting?

Randy Shaver: Thanks, Joe. I’d like to follow up and discuss length of cut and also the setting on the processor. I’ll talk in general terms. It’s important to realize there’s a lot of different types of equipment and processors out in the field today. You really need to work with your equipment supplier or equipment dealer to make sure you’ve got the correct settings on the length of cut as well as the processor. In general terms, if we have a chopper that’s not fitted with an on-board processor, we normally chop that quite fine or finer than we would with a processed silage to use the chopping or knives to break up the cob and also the kernels. Typically, we’re at a 3/8 inch or a 9-10 mm theoretical length of cut setting on a traditional chopper without an on-board processor. When we go into our conventional kernel processor type systems, there we’re usually at a 19 mm theoretical length of cut or 3/4 of an inch and the processor setting is anywhere from 1 to 2 mm. Now we also have some newer types of equipment with a greater speed differential and some more novel type processors where we’re seeing theoretical length of cuts of 26 mm, so approaching 1 inch theoretical length of cut. That processor is set somewhere in the area of 1-2 mm roll gap spacing. Again, those are some general guidelines but certainly consult with your equipment dealer to make sure that you’re getting it right for the specific equipment. I do want to mention just one more thing and that is if we’re getting silage drier than we would like it, we need to chop finer whereas some of the wetter material we can actually chop coarser. There is some movement, again, depending on the type of chopper and depending on whether that silage is on the wet-side or the dry-side. I’d like to turn this over to John Shutske and have him discuss some of the safety aspects of the harvest.

John Shutske: Most of the listeners know that farms are pretty dangerous places and they can actually be unforgiving. Late summer and the fall season that’s coming up here is a particularly high-risk time. Here in Wisconsin we have a pretty tight window of time to get things harvested before winter rolls around. It’s that urgency and time pressure that can sometimes contribute to mistakes and those mistakes often can lead to injuries and sometimes even death. Machinery does play a major role with some of our serious farm injuries. The shortcuts and the mistakes people make can be deadly. Things like power take off entanglements, getting wrapped up in self-unloading forage wagon, or even rolling a tractor on a bunker are things that happen just all too often. The best way to prevent these incidents is to invest in some of the prep time to get your equipment ready for the season. Matt and Joe and Randy talked about some of the adjustments to maximize quality and to maximize the value of your crop, but there’s some other things to look at. You need to think of your role in safety the same way that an airplane pilot might do or even a race car driver. That means to establish a pre-flight checklist or a pre-NASCAR race checklist and go through a bit of a shakedown with all your equipment to make sure that all systems are go. Are the shields in place on tractors and choppers and blowers? You need to make sure you replace any questionable hydraulic hoses or bearings or belts. Again, many of the terrible farm injuries happen when these breakdowns happen. People get stressed out. They get frustrated, and they do something that they know they shouldn’t do. If you’re spending time out on the road or on the highway, make sure that your slow moving vehicle emblems, your flashers, your lighting are all fully operational and visible. Also in Wisconsin, many of our farms have hired workers that are helping with harvest. As an employer, spend some time with them. Talk with them about your expectations. The same is true if you’re hiring custom operators. You need to create and expect a culture of safety. The final thing is to make sure that everybody involved in the operation has some way to communicate. Most times that’s a smartphone. It could be a two-way radio, but also realize that text messaging or even talking on a phone while you’re working or driving is also very distracting and can lead to some additional risk. It isn’t possible to cover everything safety-wise so it’s critical to learn as much as you can about safety and to adapt these and other recommendations to fit your own individual operation. To learn more, I would encourage people to check out the website

Liz Binversie: Thank you to our wonderful panel today. If you would like to reach our specialists, you can do so by email. Tune in next time to learn more about how to tell if your corn silage processing and packing as well as storage are adequate.