Effect of Split Iron Injection to Sucking Pigs on Growth Performance and Hematological Variables in Pre- and Post-Weaning Periods

Abstract The aim of this study was to evaluate the effects of split iron injection to suckling pigs on growth performance and hematological variables in pre- and postweaning periods. A total of 23 piglets (initial body weight: 2.19 ± 0.15 kg) were allotted into 3 treatments within litter based on body weight and sex. Treatments were: 1) Iron100: 100 mg iron at d 0 of experiment (d 3-4 of age) + no additional iron injection - control), 2) Iron100/100: 100 mg iron at d 0 of experiment + 100 mg iron injection at d 9 of experiment (d 14 before weaning), and 3) Iron200: 200 mg iron at d 0 of experiment + no additional iron injection. The pigs were housed by litter in the suckling and nursery periods with a common corn-soybean meal-based diet during the entire nursery period. Body weight, hemoglobin concentrations and hematocrit were measured at d 0 (initial), 9 (second dose for the Iron100/100 treatment), 16, 23 (weaning), and 36 of experiment. Body weight and average daily gain did not differ among treatments before weaning whereas the Iron100/100 treatment had greater body weight than the Iron100 treatment at d 36 of experiment (P < 0.05; 10.17, 12.55, and 11.45 kg for the Iron100, Iron100/100 and Iron200 treatments, respectively) and the Iron100/100 treatment had greater average daily gain in d 23-36 of experiment than the Iron100 (P< 0.05) and Iron200 (P = 0.08) treatments (0.112, 0.238, and 0.156 kg/d for Iron100, Iron100/100 and Iron200 treatments, respectively). At d 9 of experiment, the Iron200 treatment had greater hematocrit than the Iron100 and Iron100/100 treatments (P < 0.05; 30.35, 29.88, and 33.85% for Iron100, Iron100/100, and Iron200 treatments, respectively) and tended to have greater hemoglobin levels than the Iron100/100 treatment (P = 0.06). At d 16 and 23 (weaning) of experiment, hemoglobin concentrations and hematocrit were greater in the Iron100/100 and Iron200 treatments (P < 0.05) than the Iron100 treatment (9.39, 11.66, and 11.41 g/dL for Iron100, Iron100/100, and Iron200 treatments, respectively for hemoglobin concentrations at d 23 of experiment). At d 36 of experiment, hemoglobin concentrations tended to be greater in the Iron200 treatment than the Iron100 treatment (P = 0.09) and hematocrit were greater in the Iron100/100 (P = 0.10) and Iron200 (P < 0.05) treatments than the Iron100 treatment (29.73, 31.56, and 33.54% for the Iron100, Iron100/100, and Iron200 treatments, respectively) with greater values (P = 0.10) in the Iron200 treatment than the Iron100/100 treatment. In conclusion, the piglets that received low level of iron at birth had decreased growth rate and hematological variable values while split iron injection could increase growth rate after weaning even though it maintained postweaning hematocrit slightly less than high level of iron injection at birth.