The control of microbial diseases in animals: alternatives to the use of antibiotics.

In animal husbandry the control and prevention of infectious diseases is of basic economic importance. The introduction of antibiotics to treat bacterial infections almost 50 years ago led to a dramatic improvement in animal production. The emergence of antibiotic resistant strains demonstrates that the treatment of bacterial infections can not rely on the use of antibiotics without some critical consideration. Special attention has been paid to the use of antibiotics in animals including antimicrobial growth promoters because these can contribute to the problems with antibiotic resistance in humans. This has strongly emphasized the need to introduce disease preventive methods. A theory and methods for the prevention of diseases is presented that is based upon the effect on the target animal population of microbial exposure, defence and immunity to infections and combinations of these. It is emphasized that antibiotics should be an integral part of other disease preventive methods and used only when other methods have failed. They should not be included in the first line of action.