Figure 5. Bronchial N-PCR results for the challenged pigs at the 2 necropsy times. B1: pigs sired by boar 1; B2: pigs sired by boar 2; B3: pigs sired by boar 3. Scores: 0 = negative to N-PCR; 1 = positive only to the second reaction of the N-PCR; 2 = strongly positive only to the second reaction of the N-PCR; 3 = positive to the first reaction of the N-PCR; 4 = strongly positive to the first reaction of the N-PCR.