Which statement about horse digestion is correct?

• A. The stomach is the primary site of microbial fermentation
• B. The cecum houses microbes that ferment cellulose
• C. The small intestine houses most cellulose digestion
• D. Horses do not rely on microbial digestion

Answer: (B)

In horses, breaking down fibrous plant material relies on microbes living in the hindgut. The cecum is a large fermentation chamber where microbes ferment cellulose from the roughage, producing volatile fatty acids that the horse can absorb and use for energy. This is why the statement about the cecum housing microbes that ferment cellulose is correct.

The stomach is mainly for initial chemical digestion and acid/enzyme action, not for microbial fermentation of cellulose. The small intestine handles most of the enzymatic digestion of starches and proteins, and the horse’s own enzymes don’t efficiently digest cellulose. Horses do rely on microbial digestion to extract energy from fiber, so the idea that they do not rely on microbial digestion isn’t accurate.