Most common cow blood cancer - leukemia . Cows infected with leukemia dangerous that carry the disease through blood and milk . To avoid infecting cows with leukemia, they make annual vaccinations and examine them from this and other diseases. If a cow is healthy, she was given a special passport to allow the consumption of milk. Collect dairy dairy can only when there is a passport.
In addition, the cow can carry tuberculosis , rabies and plague . Often under the skin of cows live larvae blind and other insects . These larvae feed on the blood of cows and can reduce the amount of blood from the cow almost one percent.