Fermentation, specifically the presence of lactic acid, breaks down the protein matrix in the corn endosperm or starch portion. This opens up the matrix and allows greater access by rumen microbes and enzymes in the small intestine, which leads to greater digestion.
Several animal related factors can affect the utilization of corn starch in the rumen. These include:
- the amount of dry matter intake. The more the animal eats, generally the less total time it will be in the rumen due to a higher turnover rate. The rate feed particles move out of the rumen is mainly due to size and density of the particle;
- higher producing cows tend eat more of higher quality feed, which is digested faster and moves out faster than a dry cow on poor quality hay;
- having a balanced ration with adequate fiber to maintain a good rumen mat will avoid sub-clinical acidosis and will slow rumen passage rate. This will also keep more corn grain in the rumen mat and not sink to the bottom;
- other sources of starch, sugars and carbohydrates can affect rumen pH as well as rumen buffers, forage to concentrate ratio levels, forage particle size, moisture level of the TMR, and sorting of the diet in the bunk.
So how do we apply all of this to make better use of our corn and increase profits? First, start with a check of the basics that have to be done anyway. Strive to feed all animals a consistent diet that is properly balanced for fiber, starch and other requirements. Beyond the basics, consider these things for the future if you are not doing them already:
- Get information on the amount of prolamin in the corn endosperm. Identify those hybrids that have a softer endosperm.
- Consider going to high moisture corn if not currently using it and grind or roll fine. Have a three month supply carryover every year to allow new crop corn to ferment adequately.
- Harvest high moisture shelled corn at 28-30 percent, ear corn at 30-32 percent and snaplage at 34-35 percent.
- Process snaplage and grind fine enough to not have any snaplage in the top box of a Penn State shaker box.
- Process your corn silage and harvest at 65-68 percent moisture.
- Choose silage specific corn hybrids.
Source: University of Minnesota Extension