The governors say Canada's actions could cost the US economy hundreds of millions of dollars.
Trump levelled the threats - some of his strongest-ever anti-Canadian rhetoric - during an event at a Wisconsin factory where he unveiled his "Buy American-Hire American" executive order.
Trudeau signalled that he is optimistic he can persuade Trump, saying the US president is "unlike many politicians" and avoids the instinct to "stick with" a particular position.
He appeared to be taking dead aim at the industry, its coveted supply-management system long a sacred political cow in Canada, during an appearance in Wisconsin, a state he took from the Democrats with his "America First" anti-trade message. The policies target exports of ultra-filtered milk.
Friction between NY and Canada - the state's largest global trade partner - created by "protectionist" milk policies north of the border isn't cooling down.
Republican Wisconsin Gov. Scott Walker and Democratic New York Gov. Andrew Cuomo sent Trump a letter on Tuesday urging him to take action. It had been duty free but Canada changed course after milk producers there complained.
The current system limits the amount of dairy and poultry Canada can import before a tariff kicks in. Trade between Canada and NY totaled $32.93 billion in goods and supported more than 500,000 jobs.
Last month, a free-market think tank suggested using more open trade in the dairy sector as a bargaining chip in upcoming trade negotiations with the U.S.in exchange for more stable trade in softwood lumber. "It's your own responsibility, as a country, to manage your production", a spokesperson for Dairy Farmers of Canada told the Milwaukee Journal-Sentinel last week.
U.S. dairy trade with Mexico has jumped by 558 percent since NAFTA's implementation in 1994, according to the U.S. Dairy Export Council.
"We're going to get together and we're going to call Canada, and we're going to say, 'What happened?' And they might give us an answer, but we're going to get the solution and not just the answer, because we know what the solution is".
Trudeau made his remarks prior to Trump's latest anti-Canadian invective, in which the USA president again called out Canada - this time from the Oval Office - as "a disgrace" for hurting American dairy farmers. Walker said he also planned to talk privately with Trump about the issue during his stop in Wisconsin on Tuesday.
"Decision makers make statements that indicate a position that they intend to take and we're in the business of responding to positions that are actually taken", Carr said when asked about Trump's comments.
"What's happened to you is very, very unfair".
Trump also criticized the USA trading regime, which calls for a waiting period, and consultations that can stretch to three months or beyond.
Some hope that President Donald Trump will renegotiate NAFTA, a promise he ran on during the 2016 campaign.
"The whole thing is ridiculous". "It's corn and soy also that go down there so our huge trading partner and we need that market".
Relations with the U.S. are crucial for Canada, since more than 75 percent of its exports go to the U.S. Eighteen percent of U.S. exports go to Canada.