US officials have yet to reply to Canada’s request for an easing of the current temporary ban on Canadian beef and cattle, and do not have a clear timetable for a decision.

Last week Ottawa sent a letter to the US Department of Agriculture asking that it allow shipments of low-risk beef products to resume.

“I’m not sure how quickly we’ll have an answer,” US Agriculture Secretary Ann Veneman was quoted by Reuters as saying.

Meanwhile, in Ottawa, a spokesman for Canadian Agriculture Minister Lyle Vanclief said weekend discussions with the USDA had not yet yielded a timeframe for an easing of the ban, which has been in place since the discovery on 20 May of a single case of mad cow disease in Alberta.

No other cases of the disease have been discovered in Canada, although scientists have not yet been able to determine how the cow caught the disease.

“I’m not sure there will be a definitive answer as to what exactly caused it,” Veneman said after meeting with a biotechnology advisory group.