Good News on Milk Production

From here

One of the keys to higher production and higher profits is to increase the milk yield while raising fewer cows. Between 1950 and 2000, the number of dairy cows in the United States fell by more than half, yet during that same period, the average annual milk yield more than tripled. What made this possible, and how has it affected the welfare of the animals?

Wow that is some serious productivity growth and from what my Agronomist friends their is still a lot of gains to made by bringing the lower producers up to the best producers. That is without new breeds or new technology.