American labor productivity is surging (for dairy cows)

When we think about productivity in an economy, we are normally referring to the output of human workers. But some segments of the economy also feature a nonhuman labor force.

Dairy cows, for example, are a key part of the milk industry. And according to this striking chart from the US Department of Agriculture, their productivity has surged over the past generation:

Cow wages, presumably, have not increased commensurately during this period.