I didn’t get from the article why. Is it a capacity issue?
Blame ethanol made from corn, based on a stupid mandate from congress they refuse to change despite all signs leading to disaster.
When cattle ranchers and dairy farmers cannot get adequate corn, they feed their cattle less nutritious blends of food. This not only means that cattle are leaner and their meat less tasty and more expensive, but that there is less milk fat in their milk. And less milk. So less butter. And the price of milk and butter go up.
The other factor is increasing demand for US milk and dairy products by other countries. If farmers make more money exporting, they export.
Continued ethanol mandates consuming corn crop. Corn crop and other animal feeds down due to serious drought in the West. No food for animals, high milk prices.