Effects of early gestational parenteral iron administration on maternal iron biomarkers and reproductive performance in sows under commercial conditions

Abstract This study evaluated the effects of early-gestation parenteral iron dextran administration on maternal iron status and reproductive performance in sows under commercial conditions. A total of 235 TN70 sows (parities 1 to 9, average parity 4.2) were enrolled in early gestation (30 ± 2 days of gestation) and followed through pre-weaning (19 ± 2 days of lactation). Sows were allotted by parity and initial blood hemoglobin (Hb) to one of three parenteral iron dextran treatments initiated at enrollment: 0 mg (CONFe; n = 77), administered without injection; 2,500 mg (MODFe; n = 79), administered as a single 12.5-mL intramuscular injection; or 5,000 mg (HIGHFe; n = 79), administered as two 12.5-mL intramuscular injections (2,500 mg per injection), with injections administered into the trapezius muscle. Blood Hb was measured on days 30 (enrollment) and 112 ± 2 days of gestation (pre-farrow) and day 19 ± 2 days of lactation (pre-weaning) using a HemoCue Hb 201+ system via ear-vein sampling. A subset of sows (N = 75; 25 per treatment) had jugular blood samples collected for analysis of serum iron, ferritin, total iron-binding capacity (TIBC), and plasma C-reactive protein (CRP). On day 112 of gestation, blood Hb and serum ferritin increased as iron dosage increased (linear, P = 0.016 and P = 0.046, respectively), whereas serum TIBC decreased (linear, P = 0.021). On day 19 of lactation, serum ferritin increased as iron dosage increased (linear, P = 0.036). Total born and liveborn piglets were not affected by treatment. However, stillborn rate tended to decrease as iron dosage increased (linear, P = 0.068). When evaluated within parity, stillborn rate decreased as iron dosage increased in parity 1 sows (linear, P = 0.024) and tended to decrease in sows of parity 5 or greater (linear, P = 0.097), whereas no responses were observed in intermediate parities. In conclusion, parenteral administration of iron dextran during early gestation improved sow iron status through weaning, with the greatest response generally observed at 5,000 mg. Stillborn rate also tended to decrease as iron dosage increased, with responses most evident in parity 1 sows and sows of parity 5 or greater.