Postweaning multisystemic wasting syndrome (PMWS) was first described in 1996 by CLARK and HARDING. Shortly afterwards porcine circovirus type 2 (PCV2) was identified as the causative agent for this disease syndrome. It soon became apparent that PCV2 was also associated with a number of other disease complexes which have been named collectively Porcine Circovirus associated Diseases (PCVD).
Vaccination against PCV2 along with good production practice is currently the only way to control this complex of diseases. Since 2007, four vaccines conferring either active or passive immunity have become commercially available. All of them are able to reduce viraemia and PCVD-related clinical effects such as decreased weight gain and mortality. The use of most PCV2 vaccines is recommended for piglets from 3 weeks of age onwards. One of the most commonly used vaccines is the Porcilis® PCV (MSD Animal Health, Boxmeer, The Netherlands).
The current study is randomized and blinded, and was conducted in a swine farm including a fattening unit in the Northwest of Germany. Different time points of vaccination were chosen in order to define the ideal time point for vaccination and to investigate whether a vaccination of piglets in the first week of life is conducive. 600 one-week-old piglets were allocated to three study groups á 200 pigs at random. Group Vac1 was vaccinated with Porcilis® PCV at one week of age, group Vac3 at three weeks of age and group Con received an injection with sterile saline also at three weeks of age. Vaccination applied in the 3rd week of life had a positive impact on weight development until slaughter and can definitely be preferred and recommended compared to vaccination in the 1st week of life. The results of the present study indicate that the PCV2 vaccination was effective, even when used in pigs with low titres of passively acquired maternally derived antibodies present at the time of vaccination. In pigs with higher titres of maternal antibodies, an interference with those antibodies has to be expected. An application of the PCV2 vaccine starting with the 3rd week of life can be recommended as this time point still is well ahead of typical PCV2 exposure.