MILWAUKEE (AP) — In a story April 6 about a trade dispute between the U.S. and Canada over milk, The Associated Press reported erroneously that some Canadian provinces had applied import taxes to U.S. imports of ultra-filtered milk. Canada changed its policy on pricing domestic milk to cover more dairy ingredients, leading to lower prices for Canadian products including ultra-filtered milk that compete with the U.S. product.

A corrected version of the story is below:

US-Canada trade dispute threatens livelihood of dairy farms

Dairy farms in Wisconsin and other states could be forced out of business as early as May because of a trade dispute that's halted the export of their milk to Canada

MILWAUKEE (AP) — Dairy farms in Wisconsin and other states could be forced out of business as early as May because of a trade dispute that's halted the export of their milk to Canada.

At issue is a U.S-Canada dispute over what's called "ultra-filtered milk," a protein liquid concentrate used to make cheese, the Milwaukee Journal Sentinel reported (http://bit.ly/2nLyUNC ).

Canada changed its policy on pricing domestic milk to cover more dairy ingredients, and the change that took effect in February led to lower prices for Canadian products including ultra-filtered milk that compete with the U.S. product. The U.S. says it's raised concerns about the policy change.

About 75 farms in Wisconsin have already been told that Grassland Dairy Products of Greenwood will no longer buy their milk starting in less than 30 days.

The National Milk Producers Federation said losses for the dairy industries in Wisconsin and New York alone could run into hundreds of millions of dollars.

"More broadly, tens of thousands of dairy farmers will be affected by the larger scope of what Canada is doing, which is using pricing policy to offload milk powder in global markets where it will be competing with U.S. exports," said Chris Galen, a federation spokesman.

Members of Congress from Wisconsin and New York contend Canada is violating trade agreements, and they plan to raise the issue with President Donald Trump.

Ashlee Strong, a spokeswoman for House Speaker Paul Ryan, who hails from Janesville, said Tuesday that Ryan's office is talking with Wisconsin farmers and dairy groups about options.

A group of Assembly Republicans, including Speaker Robin Vos, cited the Grassland closure in a letter to University of Wisconsin System President Ray Cross on Tuesday asking him to direct UW researchers to develop more uses for milk.

System spokeswoman Stephanie Marquis said the system has a long history of collaborating with Wisconsin's dairy industry and UW researchers continue to "generate innovative solutions to help grow and protect the milk industry in our state ... we look forward to this partnership."