Monday, September 14, 2015

High Moisture Corn and By-Products

As we move into the 2015 harvest season, many growers harvest high moisture corn for feed. The following is a summary of a publication on High Moisture Grain and Grain By-Products,

High moisture corn is, as the name implies, corn harvested before the kernels dry down, usually processed by a roller mill or hammer mill, packed into an appropriate structure and allowed to ferment. High moisture ear corn is similar to high moisture corn but it includes some portion of the cob. Snaplage includes the grain, cob, and shuck (husk leaves and shank).

Preservation of high moisture grains and grain by-products is a common practice for feeding livestock in most temperate regions of the world. High moisture storage of grain has been driven by the savings of not having to dry grain at  harvest. The moisture content of most high moisture grain is within the range of 20 to 35%, and the storage time required is usually no more than the time interval between harvests, or up to 12 months. For grain by-products, where the moisture content is much greater, the pressure for high moisture storage is also driven by cost savings. However, storage of by-products is usually for short periods of time only.

As with forages, the anaerobic fermentation during ensiling of these products is based primarily on lactic acid, but amounts produced are variable both between batches of ensiled high moisture grain and even during the storage of any given batch. Not surprisingly, ethanol is found in ensiled grain. Differences in pattern of acid and ethanol production in grain may be attributed to moisture content and form of the grain. Ensiled high moisture grains and grain by-products are prone to considerable aerobic deterioration with post-storage exposure to air. Of the potential additives to facilitate storage, propionic acid is the most successful, although it is used only when the material stands a risk of significant exposure to air during storage. Results from inoculation of high moisture grains and by-products with bacteria are inconclusive, but recent studies with bacteria producing propionic acid show promise. Recovery of dry matter and nutrients after ensiling grain and by-products is usually more than 90% and for grains is usually optimized by storing the grain in sealed structures and at a moisture content between 25 and 30%.

High moisture grains usually contain the same amount of available energy for pigs and ruminants as the corresponding dry grain. In a recent comprehensive review of feeding grains to beef cattle, it was found that high moisture corn and sorghum were not as efficiently utilized as the corresponding steam rolled dry grain. For lactating dairy cows, however, high moisture grain is used as efficiently, if not more efficiently, than the corresponding dry grain. High moisture storage of grains and by-products does not usually affect food intake.

For Further Reading:

Buchanan-Smith, J., T.K. Smith, and J.R. Morris. 2003. High Moisture Grain and Grain By-Products, p. 825-854, In D. R. Buxton, R. E. Muck and J. H. Harrison, eds. Silage Science and Technology. American Society of Agronomy, Crop Science Society of America, Soil Science Society of America.

Hoffman, P.C., R.D. Shaver, and N.M. Esser. 2010. The Chemistry of High Moisture Corn. Proc. 2010 4-State Dairy Nutrition & Management Conf., Dubuque, IA.

Wisconsin Corn Agronomy - HMC, HMEC and Snaplage

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