Vaccination with the combined administration of a live PRRS vaccine (UNISTRAIN® PRRS) and a PPV and SE vaccine (ERYSENG® PARVO) confers clinical protection against heterologous PRRSV infection.
Nowadays, combined vaccines represent the next major step for pharmaceutical companies as they work to reduce the number of vaccine injections administered to animals. HIPRA was the first company in Europe to register the combination of a modified-live PRRS vaccine with a PPV and SE vaccine. With this combination of UNISTRAIN® PRRS and ERYSENG® PARVO, fewer punctures are necessary to achieve the same excellent immunisation for the breeding herd. Moreover, the combination reduces the stress for the animals and improves animal welfare. All of these advantages increase the farm’s overall productivity.
This new combination offers obvious advantages to the swine industry in terms of management. However, it is fundamentally important to demonstrate that this combination confers proper protection to animals.
In order to demonstrate the clinical protection provided by the combined administration of UNISTRAIN® PRRS and ERYSENG® PARVO against a PRRSV challenge, a study was performed to assess the vaccinated animals’ reproductive performance.
Clinically healthy six-month-old gilts free from antibodies against PPV, E. rhusiopathiae and PRRSV were selected for the trial. Half of the animals were vaccinated with ERYSENG® PARVO (2 ml/dose) and revaccinated three weeks apart with the combination of UNISTRAIN® PRRS and ERYSENG® PARVO (2 ml/dose). Lyophilised UNISTRAIN® PRRS was reconstituted with ERYSENG® PARVO following product instructions. The rest of the animals were left as controls and received an injection of PBS using the same strategy applied to the vaccinated group. Both groups were vaccinated and revaccinated seven and four weeks before mating. Then, all the animals were challenged at ninety days of gestation with a heterologous pathogenic PRRSV strain. To assess the efficacy of the combination, all the animals involved in the trial were observed daily after challenge until 28 days after farrowing and all reproductive parameters were individually recorded.
The length of the gestation period is a good parameter for evaluating whether or not the gestation process was normal. When the length of the gestation period falls outside normal limits, early farrowing (resulting in weak piglets at birth) may be suspected. Early farrowing is a typical sign of PRRS. The mean length of the gestation period was 115.1 days in the vaccinated group and 113.3 days in the control group, and was significantly lower in the non-vaccinated group. The shorter gestation length observed in non-vaccinated animals may promote the birth of weak piglets.
The combined administration of UNISTRAIN® PRRS and ERYSENG® PARVO improved the reproductive parameters of the vaccinated gilts after a heterologous PRRSV challenge. Given the major advantages that this combination represents for vaccine management and the clinical protection it provides, the combination of UNISTRAIN® PRRS and ERYSENG® PARVO is the best choice for immunising breeding herds.