On the top deck of a three-tiered structure moored near downtown Rotterdam, brown and white cows graze on hay dropped from a conveyor belt above their heads and rinds of oranges salvaged from supermarket juice machines in the port city. Canopies overhead protect the cows from sun and collect rainwater they will eventually drink.
Sometimes the Maas-Rijn-Ijssel cows — named for three Dutch rivers — walk over to a machine that automatically milks them, or they shuffle out of the way of a robot trundling past to mop up manure that will be turned into organic fertilizer.
