Consider All Your Corn Silage Harvesting Options

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The end of the corn silage harvest season is the perfect time to start planning for next year’s silage needs and begin considering all your options. Dr. Hugo Ramírez, assistant professor at Iowa State University, helps define a few less traditional silage harvesting options and their nutritional benefits. 

When harvesting traditional corn silage, the whole plant is harvested, including the stalks, leaves and everything covering the ear.

“The first thing to understand about corn silage, and why we like it so much, is that it’s a grass, so it has a slow-release energy in the form of fiber, but it also combines the benefits of a grain with starch from the kernels, which is more readily available,” said Ramírez.

A kernel processor set at a 1- to 2-mm gap should be used at harvest to smash and break up the kernels and expose the surface area of the particles to make the energy available in the kernel to microbes during fermentation in the rumen.

Depending on the weather conditions, know your plant maturity and dry matter content and target between 33% and 38% dry matter (DM) based on your harvest needs.


When harvesting snaplage, only the shank, husk, ear and cob are harvested. According to Ramírez, use of a kernel processor is “absolutely necessary” to harvest snaplage due to the dryness and hardness of the kernels. Producers are likely to turn to snaplage if corn is getting a bit too dry or if they have some extra acreage and they’d like to harvest some extra starch out of the field.

“The nutritional value is very good because it has high starch content at about 50% to 60%, which provides energy,” Ramírez noted. “Fiber digestibility can be highly variable, depending on your sample. Neutral detergent fiber (NDF) typically ranges anywhere from 15% to 18%, and protein ranges from about 6% to 8%.”

With any fermented corn crop, starch content doesn’t really change over time. However, digestibility of starch changes drastically over time. The longer it can ferment the more digestible the starch is, which is one of the advantages of fermenting snaplage and/or high-moisture corn.


When harvesting high-moisture corn (also referred to as earlage), only the grain is harvested, like harvesting field corn, except that the corn is wet relative to regular field corn.

“High-moisture corn is similar to shelled corn at 8% protein and about 60% to 65% starch, so it’s relatively high in starch content,” said Ramírez. “It’s going to have the advantage over shelled corn in that its starch digestibility will increase with time during fermentation.”

What does it mean if the starch is more digestible in the rumen? The dairy or beef producer can either feed less ground corn or shelled corn and maintain animal performance.

“The producer may actually be able to decrease both – maybe less high-moisture corn and less ground corn – because he/she already has met what the animals need in terms of rumen starch availability due to the increased starch digestibility over time,” he explained.

Ramírez’s Top Priorities to Making Quality Silage

  1. Content of dry matter. Be aware of plant maturity.
  2. Chopping length and particle size matter; kernel processing is a must.
  3. Compaction is critical to the packing process.
  4. Cover to seal out the oxygen for a good fermentation.
  5. Care and management of the bunker face means cutting across the entire face in one single day to maintain fresh feed up front.

Ramírez also noted that for both snaplage and high-moisture corn, the use of an inoculant is necessary due to the lack of soluble sugars that would normally be in the leaves and stalks.

“The microbes in an inoculant give a jump-start to the fermentation process,” he said. “Use of an inoculant would be one of the basics for all silage but is a must for snaplage and high-moisture corn.”

Ramírez also cautions producers to use extra care if they need to be near newly packed silage, as it can form nitrogen dioxide gas during the initial phase of fermentation, especially in dry or drought conditions.

“It’s important to stay away from the silage, even if it’s a bag, upright, bunker or drive-over pile,” he said. “The gas is not only corrosive, but it can be lethal. It’s an orange, brownish gas that’s typically seen the first one to three days after fermentation.”


Headline photo courtesy of Dr. Hugo Ramírez

Hugo Ramirez
Dr. Hugo Ramirez, Iowa State University

Sponsored by Lallemand Animal Nutrition