The use and standardization of multicomponent veterinary vaccines

Farming practices necessitate the use of combined vaccines for the protection of sheep, cattle and pigs. Multi-component Clostridial vaccines have been available in veterinary medicine since the late 1950s and are standardized on the basis of antibody responses in small animals and/or challenge tests. The development of new vaccines against respiratory and enteric diseases has posed a number of standardization problems as small animal models are not readily available and antibody responses do not necessarily correlate with protection. Approaches to the standardization and use of these components will be discussed.