IFNG and infection: By the start of the lambing/abortion period at week 22, and following the subcutaneous infection of group 5 control animals at week 18, all four infected groups showed statistically significantly elevated mean levels of IFN-γ compared to the uninfected group 4a sheep (group 1, Pf = 0.014; group 2, Pf = 0.001; group 3, Pf = 0.004; and group 5, Pf = 0.001).