Milk production, which was essentially nil during the Edo Period (1603-1868), did not begin in Japan until the Meiji Era (1868-1912).
But by 1975, there was already one dairy cow for every 62 Japanese people, and milk had been a standard part of school lunches for at least two decades.
Dairy farming is tough but rewarding work. It has the benefit of year-round income, but on the other hand, cows require daily early morning and evening feeding and milking. It's hard to leave the farm, and the number of sons or daughters who are taking over small enterprisedairy farms are few.