Figure 2

Proportion of pigs seropositive by age for ten seropositive herds that had completely seronegative young stock and purchased replacement gilts. x axis = Age of pigs or parity of sow (from left to right: 8 weeks, 14 weeks, gilts, parity 1, parity 2, parity 3, parity 4, parity 5+), y axis = Proportion of pigs seropositive.