PSII-16 Effect of iron injection levels and second iron injection on preweaning growth performance and hematological variables

Abstract This study was conducted to evaluate the effect of intramuscular iron-dextran injection to suckling pigs at either a high level or with two doses on preweaning growth performance and hematological variables. At d 1 of age, a total of 36 pigs (body weight = 1.56 ± 0.13 kg) from 6 sow litters with litter size greater than 10 pigs were selected, and six piglets per litter were assigned to 3 treatments based on body weight and sex. Treatments were: 1) NC: 200 mg intramuscular iron injection at d 1 of age, 2) PC: 400 mg intramuscular iron injection at d 1 of age, 3) NC+IRON: 200 mg intramuscular iron injection at d 1 of age and 200 mg iron injection at d 7 of age. The body weight, hemoglobin, and hematocrit concentrations were measured at d 1 (before initial iron injection for all treatments), 3, 7 (second dose for the NC+IRON treatment), 9, 12, and 19 (weaning) of age. A repeated measures ANOVA was used to analyze body weight, hemoglobin, and hematocrit results. There were no significant differences in body weight, hemoglobin, and hematocrit concentrations among iron injection treatments (P > 0.89) and no interactions between iron injection treatment and day of age (P > 0.64) from d 1 to 19 of age, although hemoglobin and hematocrit concentrations were numerically greater in the PC and NC+IRON treatments at d 19 of age (129.2, 133.4, and 133.82 g/dL hemoglobin for the NC, PC, and NC+IRON treatments, respectively). Hemoglobin and hematocrit concentrations declined (P < 0.01) from d 1 to 3 of age regardless of iron injection and then increased until weaning (d 19 of age; 86.9, 78.1, 87.6, 94.0, 105.7, and 132.1 g/dL hemoglobin for d 1, 3, 7, 9, 12, and 19 of age, respectively), where the hemoglobin concentrations were similar between d 1 and 7 of age (P > 0.76) whereas the hematocrit concentrations were greater at d 7 of age compared with d 1 of age (P < 0.05; 31.8% vs. 29.1%). Hemoglobin concentrations were significantly correlated with hematocrit concentrations (P < 0.01), and the correlation coefficients were greatest at d 1 and 3 of age and weaning (d 19 of age; r > 0.92). In conclusion, increased hemoglobin and hematocrit concentrations were observed in all treatments, resulting in no significant difference in the preweaning growth performance of piglets. Although the iron injection was performed at d 1 of age, hemoglobin and hematocrit concentrations decreased in the first few days of life and then increased. Hemoglobin and hematocrit values are positively correlated from birth to weaning.