A $20B mad cow class action lawsuit pitting farmers against a feed grain company and the federal government can continue, an Ontario Superior Court judge has decided.

Last week, Justice Warren Winkler dismissed a motion from Ottawa and feed grain manufacturer Ridley Inc. to quash the claim launched by an Ontario dairy cow owner on behalf of himself and about 100,000 cattle farmers.

However, the judge did dismiss the farmers' claim against the majority owner of Ridley Inc. – Ridley Corporation Ltd., an Australian company.

The damages claimed are in excess of $20 billion. The proposed class action in Ontario, Alberta, Saskatchewan and Quebec, was launched in April.

The farmers allege the federal goverment and Ridley were negligent in allowing tainted cattle feed to be sold in Canada.

After mad cow disease was detected in an Alberta cow in May 2003, the U.S. and other countries sealed their borders to Canadian cattle. The U.S. ban was partially lifted this summer, but producers say they ended up losing billions.

Ridley Inc. CEO Steve VanRoekel said Thursday in a news release he was disappointed the class action lawsuit will continue, but the company is confident it will win on the merits of its case.