Nearly every state has someone who works either with the dairy industry (if you have one) and resides in the animal or dairy science department of your state's land-grant university. If not there, someone in the agricultural economics department may work with consumer economics or keep up with economic relationships associated with a variety of industries. Short of that, each state usually has an agricultural statistics agency that might have the information. You might also check with your state department of agriculture. Sometimes industry associations in your state (or a neighboring state) may keep up with their industry data.
If you want to see what the USDA has published, go to http://usda.mannlib.cornell.edu/MannUsda/viewDocumentInfo.do?documentID=1450 as a starting point.
