Management Factors that Affect the Development of Passive Immunity in the Newborn Calf

A successful cow/calf operation requires that a large percentage of cows wean a live calf every year. A live calf at weaning time requires survival of the offspring from birth to weaning. USDA beef researchers and rancher surveys report that diseases including scours and pneumonia cause significant numbers of young calf deaths. Resistance to disease is greatly dependent on antibodies or immunoglobulins and can be either active or passive in origin. In active immunity, the body produces antibodies in response to infection or vaccination. Passive immunity gives temporary protection by transfer of certain immune substances from resistant individuals. An example of passive immunity is the passing of antibodies from dam to calf via the colostrum (or first milk after calving). This transfer only occurs during the first 24 hours following birth.