Higher ruminal pH increases in vitro digestion of diets containing dried distillers grains with solubles

Abstract

Advantages of steam flaking grain are less with respect to growth performance and diet digestion when a portion of distillers grains is substituted for grain. Ruminal pH typically is lower in cattle fed flaked-grain diets than in cattle fed rolled-grain diets. Ruminal pH for cattle fed finishing diets based on steam-flaked corn is observed below pH 6.0. Previous research observed a 5% decrease in digestion of organic matter when 13% distillers grains (dry-matter basis) was added to steam-flaked corn finishing diets. A decline in ruminal pH below 6.2 reduces activity of ruminal fiber-digesting organisms. Furthermore, ruminal protein digestion declines with pH below 5.5. It is plausible that low ruminal pH may restrict digestion of distillers grains in flaked-grain diets. The objective of this study was to examine effects of pH on in vitro fermentative activity of ruminal contents from cattle adapted to a finishing diet containing 25% dried distillers grains (dry-matter basis).