Materials, Methods & Results: The study was performed on two farrow-to-finish farms (I and II) of capacities of 2500 and
900 sows, respectively. Piglets were divided into four experimental groups: the IM group was given iron intramuscularly
on the third day of life; the SC group was given iron subcutaneously on the third day of life; the PO group was given iron
perorally on the third day of life; and the control group C was not given any iron. On the third day of life and at weaning
(day 28) piglets’ body weights were measured and their blood was taken for analysis, while at the end of the nurturing
stage (day 70), only body weights were measured. The influence of the farm was tested, as well as the impact of the day
of blood sample collection and the impact of the method of iron administration on the Fe, Hb and Hct levels, using a combined
model. These parameters were considered as fixed effects, whereas iron administration methods were considered as
randomized effects. The effect of method of iron administration on the values of Fe, Hb and Hct in the blood of piglets was
tested by ANOVA and Fisher’s post-hoc test. Piglets treated with iron had significantly (P < 0.01) higher values of Fe, Hb
and Hct, as well as improved average daily gain (ADG) and lower mortality rate than piglets which did not receive iron, in
which anemia developed. At weaning, those piglets administered iron via SC injection had higher (P < 0.01) blood levels
of Fe, Hb and Hct compared to the IM and PO groups. These piglets also produced the highest ADG, while in piglets with
IM and PO administered iron, no significant differences were observed in ADG (P > 0.05).