Corn silage and HMSC: Give them time (Dr. Eric Schwab)

Posted on January 9, 2014 in Forage Foundations
To manage feed costs, we’re looking to maximize the investment of every pound we feed.  For dairy farmers, a big part of that goal is making sure we get as much energy as possible out of our corn silage as opposed to that energy passing through to the back end.

Lately, we’ve heard a lot of discussion and claims about new technologies, including equipment and genetics, that promise improved ruminal starch access and yield. The latest harvesting equipment manufacturers suggest that advances can be made in the physical processing of corn and corn silage.  New information claims that perhaps we can identify corn hybrids that “give up” their starch more easily through changes in vitreous characteristics of the kernel.  And we know that stage of maturity and moisture have major impacts on starch availability.

These are all very worthy and important technologies to consider.  However, one factor can trump all the others, and it might be so simple we overlooked it.

That is the factor of time.

According to Dr. Eric Schwab, a member of the Vita Plus dairy nutrition and technical services team, starch, delivered as grain or silage, is best utilized if it’s fermented in the rumen where the microbial population can put it toward growth and energy production.

Time, in addition to processing, particle size, maturity and moisture content, has a huge impact on this fermentation process.  You’ve probably experienced the phenomenon that, as corn silage and high-moisture shelled corn (HMSC) age, they seem to “feed better.”  On the flip side, when young corn silage replaces aged corn silage soon after harvest, milk yield often drops.  Here’s why.

In corn silage and HMSC, prolamin-zein protein subunits hold together starch granules, acting as a barrier to digestion.  Protesase enzymes present in the forages breakdown these subunits, making that starch available for fermentation.  The more time the enzymes have to work, the more starch becomes available.

The catch here is to have an ample corn silage inventory so carryover lasts into January or February the following year.  After four to five months, starch digestibility in corn silage should approach its maximum.  In regards to HMSC, carryover is definitely a good idea.  However, the issue of practicality comes into play as research has shown that, at eight months to more than a year in storage, HMSC digestibility is still improving.

With our recent rollercoaster crop seasons, the game of carryover is a challenging one indeed.  However, planning as best you can to hold inventory for a few months before feeding can pay dividends in terms of starch availability and the resulting milk production.

Click here to access Schwab’s Dairy Performance article for further insight on this topic.

Category: Feed quality and nutrition
Forage Foundations
Forage storage and management