Dan Barber is a sort of hipster of Local Food. He cooked it before it was cool and mainstream. At Stone Barns, a center for food and agriculture just outside NYC, Barber serves something called, "Single Udder Butter." The title says it all -- the butter comes from one specific udder. This allows for variations based on time of year, diet, and even tenacity of the cow. Barber likes the idea of variation in food -- taste should be changing constantly, making chefs' lives interesting.
Fluctuations in flavors aren't usually noticeable in our industrial food system. We pasteurize our milk to ensure that flavor remains homogeneous and we feed our cows grain, instead of allowing them to forage as they do naturally. Barber feels that allowing the sale of raw milk, which is currently illegal in the state of NY and much of America, is not just a matter of taste, but a matter of animal welfare and environmental protection. Cows are not happy being fed grain that they aren't designed to eat. Moreover, that grain comes from transgenic crops in Iowa that pollute the Gulf of Mexico with nitrogen.
Maybe this is a case in which less regulation is actually safer?
Is Raw Milk Worth It? from The New Yorker