Variability in the Chemical Composition of Seventeen Selected By-Product Feedstuffs Used by the California Dairy Industry

The objective of this descriptive study was to measure the amount of variability existing in the composition of 17 selected by-product feedstuffs typically used in lactating cow rations in California. Byproduct feedstuffs are important ingredients in the diets of lactating dairy cows in California. Little information exists on the nutrient composition and variability in composition for many by-product feedstuffs. A total of 17 by-product feedstuffs were evaluated in a descriptive study. Samples were obtained from one source for all by-products except almond hulls. In most cases, the source from which samples were obtained was also the site generating the individual byproduct feedstuff. Variability in the chemical composition is discussed for each feedstuff individually, but in general the variation was not large. Differences in chemical composition were observed for some by-products compared with previously reported data. The project was a collaborative effort involving the California ARPAS chapter, industry representatives, the California Department of Food and Agriculture, and University of California, Davis.