Here's why:
* Cellulose is a complex carbohydrate: It's made up of long chains of glucose molecules that are difficult to break down.
* Cows lack the necessary enzyme: Cows don't produce the enzyme cellulase, which is required to break down cellulose.
* Symbiotic relationship: Cows rely on bacteria in their rumen (the first chamber of their stomach) to digest cellulose. These bacteria produce cellulase and break down the cellulose into usable nutrients for the cow.
Even though cows can't digest cellulose directly, they can still get nutrition from it thanks to the bacteria in their rumen.
