7 things to think about when you get into new-crop corn silage

Posted on February 21, 2023 in Forage Foundations
By Keith Lesmeister, Ph.D., Vita Plus dairy specialist and Michelle Chang-Der Bedrosian, Ph.D., Vita Plus forage specialist
The silo was sealed well, the applicator was winterized, the chopper was cleaned and put away, and hopefully, the harvest crew finally caught up on some much-needed sleep.  Temperatures dropped and, hopefully, so did the silage pH.  Now it’s time to start feeding that corn silage.

Many farmers are starting to feed their new-crop corn silage. Here are seven things to consider to make sure you get the most from each acre and ton of silage:

1. Safety: We often hear about silage avalanches this time of year.  An avalanche happens when one mass (snow, silage, gravel) shrinks or shifts at a different rate than an adjacent mass, thus removing the “anchor” that once stabilized it.  With silage, this happens most commonly when an unfermented crop is pushed against another already fermented crop, and it shrinks at a different rate.  As we get into the new crop of corn silage, it is especially important to keep safety at the forefront.  Wear your safety vest, slope silages away from you, don’t dwell near the silage face and tell someone whenever you approach the face of a silo.

Safety also should be at the forefront when opening new silages.  Silages in the “toe” of the pile or bunker, the end of the bag, and the top of a silo typically have a poorer density than in the middle of a silo.  Therefore, these silages can have some dangerous microorganisms growing in them that can negatively impact human health.  Wear gloves and a mask when handling these silages and remember to wash your hands afterward to avoid silage microorganism-related sickness.

2. Mycotoxins: One of the reasons silage microorganisms can be dangerous is the presence of mycotoxins, which are produced by molds in the field and in the silo.  Mold does not need to be visible for mycotoxins to be present.  Clean-looking silages can be high in mycotoxins if the mycotoxins were produced in the field (as most are), and many common storage molds do not produce mycotoxins, no matter how big the population.  Many producers, once they get past the toe of a silo, find it useful to test a representative sample for the presence of mycotoxins in every single silo.  Proactively knowing about mycotoxins before animals drop in production or reproduction can save money, time, and frustration.

3. Nutrient testing: The major question that most producers ask when getting into a new crop is “how will it feed?”  To answer this, a sample needs to be sent to a laboratory for testing.  Take a representative sample using proper sampling practices as an inaccurate sample can waste more money than simply the cost of the laboratory analysis.  A good place to start to measure forage quality would be to look at moisture content, pH, NDF-D, uNDF240, fiber kd, starch-D and starch percentage.  A good nutritionist can help evaluate silage quality by using a laboratory nutrient test.

4. Kernel processing: Another box to check when submitting a sample to a laboratory is corn silage processing score (CSPS).  This can help to give an idea of how much of the starch is available for rumen bacteria to digest.  According to Luiz Ferraretto, University of Wisconsin-Madison, CSPS will increase with fermentation, usually five to 10 percentage points between freshly chopped forage and fermented silage.  A good rule of thumb for a CSPS goal is to multiply the dry matter (DM) content by two and subtract five.  This means that, for silage ensiled at 33% DM, a good CSPS goal is 61%, but, for silage ensiled at 40% DM, a CSPS goal is 75%.  If the CSPS target is continually not met, focus on how to improve processing in the coming years.

5. Storage time: After the silo is sealed, we still have a very valuable tool in our toolbelt to manipulate starch availability: time.  The longer the silage sits in the silo, the more available the starch for rumen fermentation and subsequent milk production.  This is because, over time, starch digestibility increases due to enzymes from the plant and from the bacteria in the silage.  Storage time is more impactful than processing score at increasing starch digestibility, so planning for carryover inventory can go a long way.

6. Spoilage: When a new silo is opened, a certain amount of “toe crud” or “end-of-bunk funk” will be present; however, as you get into the silage, this “off” portion should go away.  If the spoilage continues, consider where in the silo the spoilage is occurring and how it can be avoided in the future.  If you consistently see surface spoilage, consider using oxygen barrier plastic with future harvests.  If the spoilage permeates the rest of the silage, consider using an L. buchneri-based inoculant.  If spoilage is present now, in cold weather, it definitely will be present and more severe as the temperature increases.

7. How to feed the new crop: Any abrupt change in the rumen has the potential to impact production; however, the rumen can handle quite a bit if the adaptation is done gradually.  Ideally, the transition from old crop to new crop would be done by blending the two silages together and ensuring adequate carryover inventory to provide a minimum of three months of ensiling time.

When this carryover inventory is not available, many nutritionists will consider increasing ground corn and urea levels to account for the loss in starch availability and soluble protein, respectively.  This also is one of the most effective times to add yeast and a buffer into the diet to help with rumen stability.

Change always presents new challenges and the transition from one crop to another is no exception; however, it can be managed in a way that sets up the animals for a safe, smooth, and healthy transition.

Category: Forage Foundations
Forage harvesting
Forage storage and management