How are cows able to get nutrition out of just eating leaves and grass?

Cows are able to extract nutrition from leaves and grass due to their unique digestive system, which includes a four-chambered stomach. This system allows them to effectively break down cellulose from plant materials through fermentation, aided by beneficial microbes. The process involves regurgitating and re-chewing their food, known as rumination, which enhances nutrient absorption. As a result, cows can convert fibrous plant matter into energy and essential nutrients.