In this study, intranasal inoculation of rabbits with P. multocida caused a marked reduction in RBCs count, PCV% and Hb concentration as well as macrocytic hypochromic anaemia (on 1st day post‐treatment) and microcytic hypochromic anaemia (on 7th day post‐treatment) in contrast to the control group. Here, GSTM1 is linked to anemia (phenotype).