A WTO dispute panel agreed with their complaint that U.S. mandatory labeling laws were too stringent, giving U.S. cattle and hog sales an unfair advantage over imports from Mexico and Canada.
The panel said the U.S. rules, so called country of origin labeling, or COOL, violated WTO rules on technical barriers to trade.
The WTO's final report marks a clear win for Canadian livestock producers, Canadian Agriculture Minister Gerry Ritz said. This is a vital first step on the road to recovery.
The country of origin labeling law, also called COOL, came into effect in 2008, prompting a sharp drop in U.S. cattle and hog imports from Canada.
Canadian cattle shipments to the United States have fallen by more than half, and hog exports to the United States are down 40 percent so far in 2011 from the volume three years ago.
Following the WTO ruling, the U.S. Trade Representative's Office said it is considering all options, including an appeal.
Although the panel disagreed with the specifics of how the United States designed those requirements, we remain committed to providing consumers with accurate and relevant information with respect to the origin of meat products that they buy at the retail level, the USTR said.