Actinomycosis and Actinobacillosis

nated in the fall to insure protection during the fall and winter. Some cattle owners in badly infected areas follow the practice of vaccinating every 6 months all animals between the ages of 2 and I o months. A product known as antiblackleg serum is sometimes used for immunizing valuable calves exposed in outbreaks. This product immediately increases the animal's resistance to blackleg, but the type of immunity it confers ceases after about 2 weeks. In some blackleg districts wehere the soil is also believed to be infected with the organism that causes malignant edema infection in animals, a bivalent or mixed bacterin containing both organisms and known as Clostridium chauvoei-septicus bacterin has been used for the prevention of both blackleg and malignant edema.