Best practices for high moisture shelled corn and snaplage harvest

By Mark Case, Vita Plus dairy specialist
I have been working in the dairy industry for more than 18 years, and, in that time, I’ve heard many people share different ideas about the best practices to harvest corn for high moisture shelled corn (HMSC) or snaplage.  Some of the strategies I have heard were just a little different from what works in my brain, so I dug into what the experts have to say on the topic.

The key to harvesting HMSC and snaplage correctly is harvesting the grain at the correct moisture levels or maturity.  I recommend going out into the field and hand-shelling corn to check moisture content.  If the kernel moisture content is around 30%, then it should be ready for harvest.  However, others would say, especially with snaplage, the moisture content of the cob and the kernels is more important.  So, which method is correct to decide if it is time for harvest?

As it turns out, both are viable options.  According to the University of Wisconsin-Extension Team Forage, recommended snaplage moisture levels are between 32% and 40%, and recommended kernel moisture content is between 28% and 35%, with harvest beginning at the black layer (34% to 35% kernel moisture) to maximize starch accumulation.

Ideal HMSC moisture levels are between 25% and 30% moisture.  Drier HMSC (less than 25% moisture) doesn’t process well, it holds air (which is what yeasts need to grow), and it doesn’t feed particularly well.  HMSC ensiled at a higher moisture content will feed fine intially after fermentation, but once the protein-starch matrix dissolves after a few months, starch digestion becomes too fast, which can cause digestive upsets.

As with most harvest practices, a successful HMSC and snaplage harvest comes down to getting the basics right.  If kernel moisture levels are too high, starch content will be reduced and you run the risk of excessive starch degradation, which can lead to acidosis or low butterfat.  If kernel moisture levels are too dry, you have a higher risk for spoilage, a less efficient fermentation, and less available starch for the cows.  For snaplage, the finished feed can also be “trashy” and not as palatable, which can lead to sorting in the feedbunk.

For both HMSC and snaplage, it is important to properly adjust your harvest equipment.  For HMSC, it is critical the grain is processed adequately.  Drier corn will need to be ground more finely than wetter corn.  For snaplage, the harvester should be set so the theoretical length of cut (TLOC) is as fine as possible and roller speeds are slowed down.  UW-Extension recommends a TLOC of 0.35 inches and a 1 mm processer gap.  This will ensure you get a fine, consistent end product.

As with all forages, make sure both feeds are packed adequately in storage structures.  When it comes time to feed, the feedout rate will need to be greater for snaplage than HMSC because snaplage is lower in density and will spoil faster.

Lastly, don’t forget to use a forage inoculant proven to prevent spoilage, such as Vita Plus Crop-N-Rich^® Buchneri.  Using the correct inoculant will help keep the feed fresh in storage and in the feedbunk.

Both HMSC and snaplage can be fed successfully on farms, but it is critical to harvest and store each feed correctly for the best results.  Vita Plus forage consultants have experience harvesting and managing both feeds; contact them to learn more.