Vaccination plays an important role in health management of production animals, and has known a growing interest since the ban on the use of antibiotic growth promotors in animal production and is an important tool to reduce the use of therapeutic antibiotics.  The primary reason for vaccinating livestock is to reduce the losses due to morbidity and mortality caused by all kind of pathogens, from viruses to bacteria and parasites. Consequently, there are plenty of diseases that are prevented by vaccinating animals against them. A vaccine helps to prevent a disease by boosting the animals’ immune system to produce antibodies that in turn fight the invading pathogen, protecting them against disease caused by this specific invader. Certain diseases are too widespread or difficult to eradicate and require a routine vaccination program. Vaccines can contribute greatly to the welfare of animals.  However, vaccination can never provide 100% protection against infectious diseases.  It is only one but a very important part of a complex preventive policy, of which biosecurity, hygiene and nutritional programs etc. are equally essential components.

There are a lot of factors determining vaccination efficiency. A vaccination failure is defined as: “when the animals do not develop adequate antibody titer levels and/or are susceptible to a field disease outbreak, following vaccine administration”. Often the vaccine is blamed, but a lot can go wrong in between vaccine development and preparation, and the production of protective antibodies by the animal, so other factors need to be considered:

  • Vaccination program is not adapted to the herd/flock’s health situation
  • Wrong administration or handling of the vaccine
  • Interference of maternal antibodies with the vaccine strain
  • Poor management: without cleaning and disinfection
  • Sanitary status: birds are already infected
  • Vaccine quality or strain is not up to date
  • Impaired immune response of the animal due to stress/disease/ …
  • Immunosuppression in YOPI (young /old/pregnant/immunodeficient) group


One factor can be easily improved compared to the other. Correct preparation and interpretation of vaccine instructions leads to a perfect administration. Measuring vaccine efficiencies can be done by antibody titer measurement at least 2 weeks after vaccination. Monitoring these titers is primordial to guarantee efficient vaccination and to allow adjustment of vaccination programs. A tool in improving vaccination efficiency not systematically used yet, is the use of an in feed supplementation modulating the immune system. Research has shown response to vaccination can be improved by using immune modulating ingredients administered through the feed, such as beta-glucans.