Bulk density of individual cereals is correlated with energy value and protein content. In North America, the usual measurement is bushel weight, while the common metric equivalent is kg/hl. Weight of 100 kernels of cereal is also used as an indicator of bulk density. Under normal growing conditions, as bulk density declines, there is usually a reduction in energy level, mainly associated with reduction in starch content of the endosperm. Concurrently protein content often increases since protein is commonly found in the outer bran or pericarp layers. Bulk density is also a useful measure for calculation of needs for storage space within the mill.
Bulk density will vary with moisture content, and this should be taken into account during measurement. Density is easily measured by weighing the cereal or feed into a container of known volume. The smaller the container, the greater the care needed in standardizing the filling and especially the packing of the ingredient. Bulk density values are not always additive and so the density of a mash feed cannot always be predicted from knowledge of bulk density of component ingredients. This situation arises, because of 'mixing' of particles of different size within a feed, so affecting the empty space common with low bulk density ingredients such as wheat shorts or alfalfa meal.
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