What feed component is most effectively digested by fermentation in the rumen and cecum?

In ruminants, fibrous feed components, particularly cellulose and hemicellulose found in plant cell walls, are most effectively digested by fermentation in the rumen. This fermentation process is facilitated by a diverse population of microorganisms, including bacteria, protozoa, and fungi, which break down these complex carbohydrates into simpler compounds. In the cecum of non-ruminant herbivores, such as horses, similar fermentation occurs, allowing for the digestion of fibrous materials. Overall, fiber is the key component that benefits from fermentation in both the rumen and cecum.