BVDV spread in a beef cow-calf herd according to virus introduction and herd size. Three types of initial virus introduction were considered: in week 27 (solid line), in week 40 (dashed line), in weeks 20, 25 and 30 (dotted line). Three herd sizes were considered: 42 (on the left), 83 (on the middle), 125 bred females (on the right). The first row shows the probability of virus persistence in the herd over time. The second row shows the median values (with for medium herds an 80% credible interval shown for intro_week = 27 on the small figure) of the prevalence of transiently (T) and persistently infected (PI) animals in the herd, and of immune dams carrying a PI fetus (RP) among bred females. The third row shows the median values (with for medium herds an 80% credible interval shown for intro_week = 27 on the small figure) of productivity outputs: losses (red), purchases (green), sales of grassers and heifers (blue), sales of empty and fattened females (orange), and number of weaned calves (purple). Annual prevalence and productivity outputs were estimated each year considering only repetitions with the virus still present at the end of the year.