That's because dairy prices have dropped by more than input prices, and their profit margins are being squeezed.
This is a stupid idea -- mostly because the current system of regulations and price supports is meant to prevent just such an occurrence. The reason that dairy farmers are in trouble is because of government policy, not for lack of such policy. (Oh, and those policies are also responsible for the groundwater pollution that HUGE dairies produce...)
Their current attempts to help are shallow offers to add more complexity to the Rube Goldberg dairy program that the USDA currently manages for the benefit of
Bottom Line: The best way to help dairy farmers is by getting the government out of the dairy business. Those who can, will prosper; those who cannot will get off the teat and go into another business (of bribing senators, no doubt).