In the first two trials, PRRS spread within the pigs from the non-vaccinated herds. By 60 days of age, the percentage of positive pigs increased to 35 per cent. Pigs from the two unstable herds carried a wild strain of the virus into the nursery. Conclusions We conclude from these trials that vaccinating sows at weaning will increase the stability of the sow herd. This system can be applied to various aspects of the Ontario swine industry.
Producers can use the definitions of sow herd stability to evaluate the status of their herds.
Certainly, this management system has opened up opportunities for the export of Ontario genetics to countries requiring PRRS-negative pigs. Thanks to participating producers and Donaldson Livestock International. Ontario Pork funding was matched by CanAdapt. Agricultural Publishing Company Limited . Federally inspected packing plants are asking that farms supplying pigs to their plants be CQA validated by the end of 1999.