Examples of milking technology from the 20th century. For thousands of years cows and other animals had been milked by hand. With the invention of small pumps powered by petrol or diesel, mechanical milking machines became the norm by 1950. Numbers of cows could be milked simultaneously in a milking parlour and far fewer workers were required. The milking cluster (bottom left) consists of four suction tubes that attach to the cow's teats and a container (centre left) to collect the milk.