The prevalence of leukosis within the Holstein breed in Canada is beyond what anyone would expect. It has been found that 12-15% of all Holstein animals in Canada are tested seropositive.  It is a disease within a group of ‘production limiting diseases” – a sickness caused by a pathogen that is both untreatable and life-long.  In Canada, there are only 26 out of 12,746 mi lking dairy herds that are certified leucosis free. Click here to read full article By Lorene Vanderwal, BC