If you got a some raw milk, could you then use a small sample of that to culture regular grocery-store milk or make homemade yogurt? It seems to me that if it's the bacteria that are beneficial, you could grow more in a readily available medium such as pasteurized milk, once you got a supply from raw milk. I could be wrong, though; I'm not a biologist!
Have you tried colostrum? I never have, but I've heard good reports and it seems like it might be beneficial.