| Summary |
Pigs with g weeks of age were immunized with 1/100 and 1/500 dosage of LPC-china and LPC-TS strain virus. The sentinels and one of the two pigs vaccin-ated with 1/500 dosage of both vaccines were killed with signs of illness, viremia and shedding after challenge exposure. The remainders survived without showing
signs.
In field trial, 16 litters of suckling piglets were designed into 4 groups. 4 litters in each group. They were vaccinated once or twice at precolostrum, precolo-strum and 6 weeks old, 3 and 6 weeks old, and 6 weeks old with viruses of LPC-China and LPC-TS strains. AH vaccinated piglets grew up normally and no adverse reaction was observed. Two pigs from each Jitter were ramdomly bought back at 7 weeks of age and challenged at 9 weeks old. Results showed that all vaccinated pigs survived with fibrile reaction. Nevertheless, the sentinels developed severe signs and were killed.
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