Corn Silage Harvest Reminders

By:  Allan Vyhnalek

High-quality corn silage often is an economical substitute for some of the grain in finishing and in dairy rations, and it can be an important winter feed for cow-calf producers. All too often, though, silage isn’t harvested at the best time for ultimate feed value.

Timing needs to be based on moisture content of the silage. Silage chopped too early and wetter than 70% moisture can run or seep and it often produces a sour, less palatable fermentation. We often get this wet silage when we rush to salvage hail or wind damaged corn. Live and green stalks, leaves, and husks almost always are more than 80% moisture, so be patient and wait until these tissues start to dry before chopping.

Normal corn though is often chopped for silage too dry, below 60% moisture. Then it’s difficult to pack the silage adequately to force out air.  The silage heats, energy and protein digestibility declines, and spoilage increases. If your silage is warm or steams during winter, it probably was too dry when chopped.

Many corn hybrids are at the ideal 60%-70% moisture as corn kernels reach the one-half milkline.  This guide isn’t perfect for all hybrids so check your own fields independently.

Corn kernels in silage between half milkline and black layer are more digestible.  Drier, more mature corn grain tends to pass through the animal more often without digesting unless processed.  Also, older leaves and stalks are less digestible.

Remember, chopping your silage at the proper moisture level can mean better feed and better profits.

The second management thought relates to the use of inoculants.  To make good silage, a little help from inoculants can improve fermentation.  When and how can you get the best use from them? There is no clear cut, consistent way to predict when inoculants will be most useful or cost effective.  Silage fermentation is just too complex.

Inoculants primarily reduce storage losses.  The most effective ones contain homolactic acid bacteria like Lactobacillus plantarum.  Fermentation starts and ends quicker with inoculated silage so more silage remains for feeding.  Typically, you save about 5 percent.  Some inoculants also improve aerobic stability by using the heterolactic acid bacteria Lactobacillus buchneri.  They reduce spoilage losses when silage is re-exposed to air, thus extending bunk life.  These bacteria are especially useful at reducing spoilage on the face of bunker silos.

Inoculants consistently improve wet silage, especially sorghum silage.  If you start chopping early enough to prevent silage from being too dry at the end, inoculants should help.

In the past, inoculants rarely improved properly made corn silage – silage at the right moisture, chopped fine, packed well, and sealed tight.  Nor did they improve dry silage.  But recently developed inoculants, with more effective strains of fermentation bacteria, are producing slightly better quality silage even from these feeds.

If you use an inoculant, make sure that it contains live bacteria.  Also check to see that the inoculant provides at least 100,000 colony forming units per gram of wet forage when applied at the recommended rate at the chopper.  You need plenty of live bacteria for the inoculant to do you any good.

But used in the right conditions, inoculants can be worth it. Bruce Anderson, UNL Forage Specialist, provided most of the information used in this week’s column.

For more information or assistance, please contact Allan Vyhnalek, Extension Educator, University of Nebraska-Lincoln, Extension in Platte County.  Phone: 402-563-4901 or e-mail