| Summary |
Pigs with low matenal antibody (1:2-1:32) v&cdnati with 2-1 ,CG) TCIIJ5O tissue culture LPOChina stain virus were challengal 10 days aft vaccination. Result showai that all cc’ntrol pigs and one of the pigs received 2 TCIIJ5O virus develored high fever and were killed. The rest of the pigs survival without signs aft challenge, Moreover, vixernia and shedding could only ke detected in those 3 victims, Pigs with high maternal antibody (l:150-l:25 vaccinatliwth 10-5,CIX)TCflJ5O tissue culture LPOChina stain virus were also challenged 10 days aft vaccination Result revealed that only one of the control pigs was Idled with high fever, vixemia and shedding. However, mild febrile reactions Irelow 40.6? were noticed in the rest of pigs. On the other hand, immune responses of the pigs with high maternal antibody (1:150- 1:214) aft giving with 10-1 QCU) TCIDSO tisue culture LPC-China stain virus were inornitoisi. Result implied that dosage of 1 OJXE) TCICSO was needed to overwhelm high maternal antibody Ierrier, and antibody respo’nse could only then It eliciti one month later.
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