Ottawa passed legislation in December that will allow western wheat and barley growers to sell their grain on the open market instead of having to go through the board.
But Goodale said Thursday it's not known how that will affect farmers and their bottom line.
"If this process goes forward, it really does constitute the biggest change in western Canadian agriculture in several generations, and it is not all clear what the consequences of all of that will be," he said.
"It seems...important to have someone in the process with credibility and expertise and independence that can monitor the changes and the consequences of the changes, measure what's going on, analyze it and report publicly on the consequences and the fallout —either good or bad — of what is about to transpire."
Goodale, who represents a Regina riding, said questions need to be answered about whether wheat and barley producers will get more or less in total returns from an open market. He also said tracking could look at whether there's a way for farmers to challenge grain companies or railways on service levels or costs.
Goodale said one option is to follow what happens for the next five years when most of the changes take place. He suggested an impartial institution such as the University of Saskatchewan track the outcome.
The new law becomes effective Aug. 1 in time for the next crop year.
The changes came after a debate that divided farmers across the Prairies. Supporters argued the board's monopoly prevented producers from competing against each other for sales and ensured better prices. They also said the new legislation leaves farmers at the mercies of railways and big, international grain companies.
Board opponents wanted the freedom to seek better deals on the open market.
Agriculture Minister Gerry Ritz said producers of other grains and wheat farmers in other parts of Canada already had that freedom.
He appeared to dismiss Goodale's call for monitoring by an independent agency.
"Our government trusts farmers and knows that farmers do their own cost-benefit analysis of their farm business every day. That is why we have given farmers the freedom to choose how to market their grain," Ritz said in an email Thursday.
Earlier in the day, he spoke to a supportive audience at the Western Canadian Wheat Growers Association's annual convention in Moose Jaw, Sask.
A Federal Court judge ruled in early December that Ritz violated the existing Canadian Wheat Board Act by making changes without consulting farmers. But Justice Douglas Campbell made it clear that his ruling was only a statement on the government's actions. He did not order Ottawa to stop the bill and said he wouldn't interfere in the legislative process.
On Dec. 16, Justice Shane Perlmutter of Queen's Bench Court in Winnipeg denied an injunction that would have put the federal government's new legislation on hold.
The matter is due back in court Jan. 17 as lawyers prepare to argue over the constitutionality of how the Conservatives brought in the law.