Grain quality is a nebulous term that means different things to corn producers, crop consultants, dairy producers or ruminant nutritionist. In commercial grain sales, grain quality is often defined in terms of moisture content, test weight, kernel size, total damaged kernels, heat damage, broken kernels or breakage susceptibility. Foreign material in grain such as molds, mycotoxins, insect fragments, and other foreign material are also used to define grain quality. Likewise, nutritional properties of corn grain such as fat, protein, hardness, density, and starch content define corn quality characteristics. In short corn grain quality is defined primarily by the end users intended use. If the end user of the grain is a dairy cow, then grain quality factors related to milk production best define grain quality.