They were first bred in the Netherlands and brought to America in 1857. These cattle are immediately recognizable by their black and white coat color; they are, so to speak, the prototype of domestic cattle. Today, black and white cattle are kept for their remarkable milk production: the average cow produces 12,000 liters of milk per year. They live for three to four years, but some have a significantly longer lifespan. Cattle have four stomachs. When kept in stalls, they eat a combination of grasses and hay, which is then regurgitated for chewing. The partially digested food is pushed back from the first stomach into the mouth, where it is chewed until it reaches a state that allows it to pass through the other three stomachs. The cows then look as if they are chewing gum.