Vaccination with a multiple clostridial disease bacterin (4-way, 7-way, or 8-way) is the basis for prevention. Two doses of vaccine (primer dose and booster dose) are required to provide a good level of protection. Calves should be vaccinated at first working and given a booster prior to or at weaning. Replacement heifers are boostered prior to breeding. Blackleg is generally not much of a risk for cattle over two years old; however, many cows receive annual boosters with a multiple clostridial bacterin containing blackleg to protect them against other agents in the vaccine such as redwater.