Classification of commonly used feed ingredients based on flow properties

The objective of this report was to classify ingredients based on their flowability. Twenty-six different feed ingredients (52 samples) were used including cereal grains, cereal by-products, oilseeds, oilseed meals, and animal-origin products. As an indication of flowability, the angle of repose was determined using a funnel test. In general, high protein oilseed meals had the lowest angle of repose, and therefore they had the highest flowability with the exception of cottonseed meal. Corn gluten feed and wheat middlings had the highest angle of repose values (39 and 34°, respectively), and therefore they had the lowest flowability. Ingredients with a range of angle of repose values between 22 and 25°, between 27 and 30°, and more than 30°, were categorized as having an easy flow, a moderate flow, and cohesive, respectively. The greater the protein content, the smaller the compressibility value (r = –0.38) and the lower the angle of repose (r = –0.42). An increase in the ether extract content of the ingredients resulted in a subsequent increase in angle of repose (r = 0.31) and therefore a decrease in flowability (p<0.05). The angle of repose was positively correlated with compressibility and the Hausner ratio. In conclusion, oilseed meals were classified as “easy flow”, most by-products as “moderate flow”, and cereal grains as “cohesive”.