Pigs in the control and weaning iron groups had a treatment mean of 9.9 g/dL ± 0.32 and 9.7 g/dL ± 0.32, respectively, indicating sub-clinical anemia, compared to the day 7 group with a treatment mean of 12.2 g/dL ± 0.32, indicating healthy Hb concentrations. Here, GSTM1 is linked to anemia.