Risk factors and control measures for subclinical salmonella infection in pig herds

In the last 20 years there was an enormous increase in pig production in several parts of the European Union. After entering of disease agents in such areas it is very easy for them to spread and to persist in the pig population. This has resulted in a situation in which a lot of pathogens continually occur in the pig population. The size of the pig farming operations and the small geographical distance between them makes it almost impossible to eliminate most of the disease agents from the populations. On the other hand there is a development in the EU-regulations that requires more and more guarantees with respect to the absence of some pathogens in the population in a non-vaccination policy. Only countries able to comply with these requirements have free entrance to the European market. A second development in this field is the increasing interest in a high quality standard of the products at the end of the pig production chain; first of all in relation to the safety of the product linked to residues and zoonoses, but further to the meat quality and at last the emotional quality for the consumer. These developments have lead to a health control policy in swine production that is based on two different tracks: the safeguarding strategy and the controlling strategy