A large dairy (800-900 ave head) a few miles from us, is almost completely self-sufficient. Grain production, milking cows as well as breeding (artf insem) and cycling through to calving (mama cows seen in first part before milking), selling the males, keeping females. The manure is run through an anaerobic fluidized bed digester which extracts the liquid part, dehydrates and sterilizes the solids, and the methane gas from the liquid is used to run generators to create renewable energy credits that they sell to the power company (earning more that way than using it themselves). The dried/sterilized manure is used for bedding and they sell it. They grow the grain for the feed on their land in Newville (some across from us).
All really amazing!
