Fig. 2.

Standard curves showing the linear relationship between cycle threshold (Ct) values and log₁₀ RNA copy numbers of viral targets. The results of 10-fold dilution series of viral RNA copy numbers are shown with each dilution run in triplicate. The mean values with standard deviation are shown, as well as equations (y) and determination coefficients ( r²). BPI3, bovine parainfluenza virus type 3; BCoV, bovine corona virus; BRSV, bovine respiratory syncytial virus; BVDV, bovine viral diarrhoea virus; BoHV-1, bovine herpesvirus 1.