Trump is targeting Canada's dairy industry. Is it time to rethink our decades-old supply management system? / Letters: Dairy cows are the heroines of the New Zealand economy / Dairy should be NZ's economic growth engine not immigration - Richard Prebble / China's multidecade dairy boom sours as population ages, sales slump / Economic woes sour prospects for China's dairy farmers / China's beleaguered dairy cows board bandwagon to revive economy / Dairy exporters in the USA gloomy over China demand outlook / Japan's struggling dairy farmers shift to wagyu, despite lean market