Canada’s farmers say that a government pledge to cover dairy losses from a new trade deal struck with the U.S. will probably fall short of what they need.

The pact, which also includes Mexico, will give the U.S. greater access to Canada’s protected dairy market, eliminate the nation’s new milk-pricing system and restrict the sector’s ability to export. While Prime Minister Justin Trudeau has promised to compensate farmers to cushion the blow, industry groups say past experience has shown that aid packages amount to a “pittance,” and the government won’t be able to cover the financial hit the industry is poised to take.

“It won’t make up for the losses,” said David Wiens, vice-president of the Dairy Farmers of Canada, an Ottawa-based industry group that represents the nation’s 12,000 producers. “It won’t be able to do anything for the fact that the dairy industry is not able to grow and will actually shrink.”

Canadian farmers are poised to lose $1 billion a year thanks to the renegotiated Nafta and previous accords with Europe and transpacific nations, the industry group said Wednesday in a statement that accused Canada of having “caved in” to U.S. demands.

The nation’s Class 7 milk policy made it cheaper for processors to buy domestic supplies of ultra-filtered milk, a concentrated ingredient used to boost protein content in cheese and yogurt. Farmers may now be forced to dump excess skim milk down the drain if the processing sector is crimped by the new agreement, Wiens said.

“How do you compensate for that?” Wiens said. “There’s a lot of frustration out there.”