After more than four years of restricted trade following a mad-cow disease scare and an estimated loss of more than $1.7 billion, Canadian producers are welcoming this month's reopening of the U.S. border to older live Canadian cattle and their meat products.

The move comes after the U.S. Department of Agriculture ruled that the risk of bovine spongiform encephalopathy (BSE) in Canadian cattle is "negligible."

The border slammed shut when BSE was first found in an Alberta cow in May 2003, costing Canadian producers about $426 million a year.

Canadian cows under 30 months of age, deemed to be at less risk for BSE, have been allowed into the United States since July 2005.

But older Canadian cattle and beef cuts from those animals had remained barred.

The trade rule now being implemented allows the import of meat from all older animals and any live cattle born after March 1999 - when a feed ban aimed at stopping the spread of BSE came into effect in Canada.

Brad Wildeman, vice-president of the Canadian Cattlemen's Association, was taking a "cautiously optimistic" approach to the border reopening.

"There's more regulations to get them down there and so there's going to be a little more work to get them into those markets," he said.

We're not expecting a flood of cattle heading down there because of this."