The Trans-Pacific Partnership cannot proceed without the US, Canada says, even after Australia and New Zealand pledged to salvage it.
US President Donald Trump withdrew from the 12-nation trade agreement on Monday, following through on an election promise days after his inauguration.
"This agreement was so constructed that it can only enter into force with the United States as a ratifying country," Foreign Affairs Minister Chrystia Freeland told reporters in Calgary on Tuesday.
"So the TPP as a deal cannot happen without the United States being a party to it."
Earlier on Tuesday, the Australian and New Zealand governments said they hoped to save the deal by encouraging China and other Asian countries to join the trade pact.
Canadian farmers produce far more grain, oilseeds and meat than the country can consume, and some farm groups had hoped to see the deal proceed.
"It's disappointing," said Robin Speer, executive director of Western Canadian Wheat Growers.
"We know trade improves productivity, innovation and supply chains, and helps drive economic growth."
Canada is one of the world's biggest exporters of wheat, beef and pork.
Ranchers were hoping to expand beef exports to Japan under lower tariffs included in TPP, said Dennis Laycraft, executive vice-president of Canadian Cattlemen's Association.
He said Canada should now focus on a trade deal with Japan.
