Experimental design. Heifers (n = 6 per group) were inoculated with BVDV on day 75 (PI group) and day 175 (TI group) of gestation. Control group was kept uninfected throughout the experiment. Black stars show days of viremia detected by qRT-PCR. Genome-wide microarray analysis, shown with white stars, was completed on day 160 of gestation [2-way analysis, comparing control heifers (n = 4) and heifers of the PI group, (n = 5)] and day 190 of gestation [3-way analysis, comparing heifers (n = 3 per group) of the control, TI, and PI groups] using Affymetrix bovine chips. Blood samples for RNA isolation were collected from all heifers on days 75, 78, 82, 90, 120, 160, 175, 178, 182, and 190 of gestation. BVDV, bovine viral diarrhea virus; PI, persistently infected; TI, transiently infected.