Fig. 1

PRRSV-antibody levels of three-week-old piglets as determined by ELISA (S/P ratios). Each triangle represents an individual. S/P ratios ≥ 0.4 are considered positive. (A) Distribution of S/P ratios for all examined animals per batch. (B) Distribution of S/P ratios for the offspring of the fourteen sows present in batches 1 and 3. Offspring from the same sow are depicted using the same colour. ns = non-significant; *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001