Dairy farming has been part of the agricultural sector for thousands of years. Historically it was a part of small and diverse farms. The last century saw the emergence of large farms focusing on milk production. Large-scale dairy farming is possible only where large quantities of milk are needed to produce more durable dairy products such as cheese and butter, or there is a significant market for people who have the money to buy milk, but do not own their own cows. Dairy farmers were the best way to meet the demand.