Interpretive Summary: Corn processing, flake density, and starch retrogradation influence ruminal solubility of starch, fiber, protein, and minerals

By: Amelia R Tanner, Victoria C Kennedy, Cameron S Lynch, Taylor K Hord, Quinton A Winger, Paul J Rozance, Russell V Anthony

Grain processing has been used for decades to improve digestibility of finishing cattle diets, leading to improved growth performance and feed efficiency. The soluble fraction of a feed can be defined as the fraction that disappears immediately in the rumen and its measurement can be useful for understanding kinetic properties of feed digestion. Grain processing methods that result in changes in particle size, flake density, or starch retrogradation have been shown to affect the soluble fraction of dry matter in the rumen. However, it is unknown how the solubility of different nutrients are affected by these changes. The objective of this experiment was to characterize how corn processing, flake density, particle size, and starch retrogradation influence the soluble fraction of starch, protein, fiber, and minerals. With each increase in the degree of corn processing, there was an increase in the solubility of nutrients. Increasing flake density can decrease ruminal solubility of flakes; however, the soluble fraction of sifted fines is not influenced as much by changes in flake density. Inducing starch retrogradation decreases ruminal solubility of starch, nonstarch OM, and minerals. Understanding the factors influencing ruminal solubility of processed corn is important when modeling digestion in beef cattle.

Read the full article on the Journal of Animal Science.