Monthly Archives: April 2010

In modern pig production, proliferative enteropathy is a common cause of diarrhoea and poor growth in young animals. This study aimed to determine the possible spread of Lawsonia intracellularis through the sale of replacement gilts and the possibility to protect the herds by adequate biosecurity measures. This was achieved by repeated sampling of 50 gilts in an infected multiplying herd, from the last day in the farrowing pen and until sale. Further, 60 gilts sold from this herd were tested during their stay in quarantine in a recipient herd. To confirm freedom from infection, 100 growing pigs in the recipient herd were also tested. Individual faecal (n = 748) and blood (n = 728) samples were analysed by PCR and ELISA, respectively. Transmission of L. intracellularis from the sows to their offspring was not demonstrated. However, the possible transmission between herds by replacement gilts was demonstrated. Peak shedding occurred at 12 and 15 weeks of age, and single animals were also PCR-positive at 24-36 weeks of age in the multiplying herd and in the quarantine in the recipient herd. Further, the possible occurrence of chronically infected carrier animals was suggested. Although L. intracellularis is widely spread, it appears possible to avoid the transmission between herds by employing adequate biosecurity measures. Thus, it would be advisable to establish herd profiles in breeding herds to avoid the selling of infected animals as well as to establish the health status of the recipient herd. Further, the health status of the recipient herds should be known.

The objectives of this study were (1) to compare the efficacy of two different PCV2 vaccination protocols (colostrum-derived immunity versus piglet vaccination) in a conventional PCV2 growing pig challenge model and (2) to evaluate the efficacy of vaccinating piglets with the same vaccine used in the dams. Two different commercially available vaccines (VAC1; VAC2) were used in the same experiment. Seventy-eight piglets born to vaccinated or non-vaccinated sows were divided into 8 groups. A proportion of the pigs with and a proportion of the pigs without passively acquired immunity were vaccinated at 21 days of age. All pigs except negative controls were challenged with PCV2b at 35 days post-vaccination and necropsied at 21 days post-challenge (dpc). The data indicates that both dam vaccination and piglet vaccination had similar efficacies in reducing PCV2 viral loads and antigen levels in the growing pigs. Interestingly, dam vaccination alone did result in significantly (P < 0.05) lower anti-PCV2-antibodies levels at challenge in piglets from dams immunized with VAC2 compared to piglets from VAC1 immunized dams. When data obtained from the growing piglets that were vaccinated with VAC1 or VAC2 were compared, antibody levels and reduction of incidence of PCV2-antigen were not different; however, piglets vaccinated with VAC2 had reduced PCV2-DNA genomic copies in serum by 21 dpc. Vaccination of piglets with the same vaccine as was used on their dams did not appear to affect vaccine efficacy as piglets in these groups had anti-PCV2-antibody levels and PCV2 genomic copies similar to the groups where vaccine was administered to the piglets only.