Evaluating and planning your corn silage

Corn silage is part of many dairy rations in Eastern Canada.  Before harvest begins, it is best to evaluate the results from last year and try to correct any weak areas.  

Was your silage harvested at the correct moisture content and maturity stage for optimal fermentation? 

Was your chop length adequate for good compaction in the silo without compromising palatability? 

For those using rollers or processors, were these adjusted so that more than 70% of kernels were cracked? The goal of these rollers is to make the starch more accessible to the microbes in the rumen. 

If more than 30% of the kernels are still whole when ensiled, we can do better than that.  More precise adjustments to the equipment before harvest should translate into better results In the milk tank.  The more the grain is worked,  the less starch we find in the manure.  

To help evaluate the kernel processing efficiency of cracker rollers, the Evironex group has developed a laboratory analysis called the corn silage processing score (CSPS or ICEM, l’Indice de conditionnement de l’ensilage de maïs). This score evaluates the percentage of starch that passes through a 4.75 mm screen, expressed as a percentage of the total starch content.

A table to interpret results has been developed by an American researcher (see table).   Corn silage with a CSPS of less than 50% will have many intact kernels.

The silage is therefore more poorly fermented by the rumen microbes. Potential result:   lower microbial protein production and propionic acid, which will result in lower quantities of milk proteins and less energy available for milk production.

Even though the CSPS increases somewhat as corn silages ages in the silo, it won’t increase enough to go from inadequate to excellent. Only a few percentage points will accumulate as Autumn progresses. 

CSPS evaluation of last year’s harvest will let you know if you have mastered fine-tuning your cracker rollers- before it is time to fill the silos again. 

Table: Corn silage processing score evaluation 

CSPS/ICEMProcessing efficiency
70% or greaterOptimum
Less than 50%Inadequately processed

Corn silage: avoiding the formation of toxic gases

The work of harvesting corn silage has begun. Here are some things to consider to avoid potential formation of toxic gases in silos.