Ontario Justice Paul B. Schabas said Canadian officials followed the science of the time in responding to BSE sweeping across the beef industry in the United Kingdom.
The plaintiffs argued Canada did not do enough to keep diseased cattle and feedstuffs out of the country.
Schabas also said Canadian government officials complied with World Organization for Animal Health guidelines.
He acknowledged that total losses were $5.419 billion, but said producers received government assistance worth $4.256 billion.
The diseased cow in Alberta died in 2003. It took until this decade for all nations to lift trade restrictions related to BSE.
There were several other later instances of Canadian cattle being diagnosed with the disease; it took examination of the brains of dead cattle to confirm that they were infected.
