Porcine circovirus type 2 (PCV2) is one of the most important pathogens in domestic swine production causing severe economic impact to farmers and farm managers. Since it was first described in the late 1990s, more and more disease syndromes have been found to be associated to PCV2. It has also been discussed that respiratory diseases could be related to PCV2, primarily in the context of the "Porcine Respiratory Disease Complex" (PRDC). Respiratory diseases in pig farming are particularly important with respect to animal health, animal welfare and economics and are also one of the main indications for the prescription and administration of antimicrobial substances.
In 2008, a nationwide vaccination programme against PCV2 was introduced in Austria and offered a unique chance to evaluate the effect of vaccination on a variety of medical and management aspects over a period of time. The main question to be addressed was the influence of PCV2 vaccination on porcine lung health. To this end, data collected routinely within a quality assurance system were analysed. The dataset included vaccination records and post-mortem findings of 247 505 fattening pigs from 72 conventional pig farms over a period of 4 years (2008 to 2011).
In order to evaluate the influence of PCV2 vaccination on the probability and severity of post-mortem findings of pneumonia, a Cumulative Link Mixed Model was used. Three major effects were observed:
(1) PCV2 vaccination significantly (P<0.01) reduced the odds (coefficient: -0.05) of post-mortem findings of mild, moderate and severe pneumonia for vaccinated pigs. (2) Regardless of vaccination status, pigs from fattening farms were significantly less likely (coefficient: -0.44; P<0.05) to exhibit signs of pneumonia at slaughter than pigs from farrow-to-finish farms. (3) When vaccinated against PCV2, the odds of detecting post-mortem signs were even lower (coefficient:
-0.19; P<0.001) for pigs from fattening farms. Combining PCV2 vaccination, farm type and interaction effects between these two factors, a pig vaccinated against PCV2 originating from a fattening farm had only half the chance (OR 0.51) of suffering from pneumonia, which was subsequently detected post-mortem, than a non-vaccinated pig from a farrow-to-finish farm.
The results of this study highlight the benefit of the implemented PCV2 vaccination programme with respect to porcine lunge health. Furthermore, the findings emphasise the usability of detailed, routinely collected data at farm level and demonstrate the importance of evaluation of management and preventive measures.
Pig health / Porcine circovirus type 2 / PCV2 / vaccination / post-mortem findings / slaughter findings / pneumonia