Yes, there are dairy cattle in Alberta that are fed genetically modified feeds. Any genetically modified feedstuffs fed to Canadian dairy cattle will have received approval from Health Canada and the Canadian Food Inspection Agency (CFIA).
Currently, there are four approved GMO crops that can be grown in Canada. These are canola, corn, soy and sugar beets. There is the possibility that other feed stuffs could be imported that contain GMOs, however these feeds would also have to have received CFIA authorization.