What is the history of the Eau Claire Rule?

In the 1960s Congress reacted to growing shortages of milk in regions of the country far from the Dairy Belt by passing the Federal Milk Marketing Order -- also known as the Eau Claire rule -- which provided a bonus for milk sales based on how far a dairy herd was from Eau Claire, Wisconsin (thought to be at the geographic center of US dairy production). The idea was that, with the bonus, dairy farmers would have an additional incentive to transport milk to such cities as Miami, Raleigh, Houston, or Newark. What happened? Although Wisconsin's cool climate leads to greater efficiencies in milk production, the bonus enticed many farmers located far from the Midwest to enter the business. In the long run, it was good for the US milk consumer, but not necessarily good for Wisconsin's dairy industry.