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An experiment was conducted to evaluate the effects of a second injection of iron dextran administered on days 6 to 8 of age.
Methods: A total of 144 crossbred pigs (equal barrows and gilts; initial age 6 to 8 d; initial body weight = 2.86 ± 0.01 kg) were assigned to either the control or an added-injection treatment. Pigs were paired by sex and body weight within a litter and randomly assigned to the iron treatment within each pair. All pigs had received an initial intramuscular injection of iron dextran (200 mg Fe) <24 h after birth. Pigs assigned to the added-injection treatment received a second intramuscular injection of iron dextran (200 mg Fe) on days 6 to 8. All pigs were weaned at 22 to 25 d, housed 6 pigs/pen, and received a common corn–soybean meal diet. Body weight and feed disappearance were recorded every 2 wk. Hemoglobin concentrations were measured at birth, initiation of experiment (days 6 to 8), weaning, and the end of the nursery and end of the study. At the end of the study, 1 pig/pen (n = 12 pigs/treatment), closest to the pen mean was selected and slaughtered for carcass characteristic measures. The individual pig served as the experimental unit for body weight, hemoglobin, average daily gain, and carcass characteristic data whereas the pen served as the experimental unit for average daily feed intake, and gain/feed ratio data.
Results: The added-injection pigs had a greater hemoglobin at weaning (13.1 vs. 10.7 g/dL, respectively) and end of the nursery (12.1 vs. 11.7 g/dL, respectively) compared to control pigs. During the finisher period, added-injection pigs had a greater average daily gain (0.94 vs. 0.91 kg, respectively) compared to control pigs. Overall, pigs receiving the second iron injection had an ~4% increase in average daily gain from weaning to the end of study. The cumulative improvement in average daily gain from weaning to the end of study observed for the added-injection treatment group resulted in added-injection pigs having a heavier body weight at the end of the study (~3 kg; P = 0.04). Following slaughter, added-injection treatment pigs had ~7.2% heavier trimmed loin compared to the control pigs.
Conclusion: Administering a second iron injection resulted in greater hemoglobin at weaning and the end of the nursery as well as improved growth performance from weaning to the end of study weight and increased carcass weight at slaughter.
Chevalier TB, Lyons W, Paczosa DB, Rentfrow GK, Lindemann MD. A second iron injection administered to piglets during lactation improves hemoglobin concentration, growth performance, and carcass characteristics at slaughter. Journal of Animal Science. 2023; 101: skad270. https://doi.org/10.1093/jas/skad270