Clostridial organisms are, for the most part, normal flora of cattle and only become problematic with dietary stress, injury, changes in management, parasitism or other unusual circumstances that set up a favorable growth environment and result in production of potent toxins. While some of the diseases rarely, if ever, occur in the US, most others occur sporadically in herds. In general, clostridial diseases carry a very poor prognosis and the first sign of illness may be death. Because treatment success is rare, emphasis is properly placed on preventive measures. Vaccines enjoy widespread use within the dairy industry and can be an efficient way to reduce losses due to these bacteria. A single vaccination with most Clostridial vaccines does not provide adequate levels of protection and must be followed within a period of 3 to 6 weeks by a booster dose. Young calf vaccination does not yield adequate protective immunity for at least 1 to 2 months so most vaccination strategies target the pregnant cow so that maximum immunity is imparted to the calf in colostrum. Inactivated commercial vaccines, which contain 2, 4, 7 or 8-way combinations of clostridial organisms, should be appropriately timed to provide maximum protection at the age of susceptibility.
Clostridium perfringens occurs widely in the environment and in the gastrointestinal (GI) tract of most mammals. Type A is routinely isolated from soil and clinically normal animals. While it is unusual to find C. perfringens type A in corn silage and high moisture corn, the organism has been found in haylage under some storage conditions. Types C and D are only rarely isolated from soil but they can be isolated from asymptomatic animals, particularly those that demonstrate an immune response in their blood. Clostridial diseases are not spread from animal to animal. Susceptible animals are those that have the organism and have one or more risk factors that are identified below. Management is critical factor in control of clostridial diseases. These bacteria proliferate after death, often to the exclusion of other normal flora, and can invade tissues beyond the gut. Thus, iso