Feeding the Prolific Sow for Success, Part I: Late-gestation Phase Feeding Improves Maternal and Progeny Micronutrient Status and Piglet Viability in Prolific Sows

Abstract As litter sizes increase, sows have greater metabolic and nutritional demands to support litter development, particularly during late gestation. This study evaluated a nutrient-enriched late-gestation phase (LGPHASE) diet on maternal and progeny biomarkers and farrowing duration. Seventy sows (parity 0–5) at 70 ± 2 days gestation were allotted by parity, body weight, previous reproductive performance, and hemoglobin (Hb) to a control (CON; n = 35; 11% CP, 0.52% SID lysine, industry-standard organic trace minerals, and vitamins) or the LGPHASE diet (n = 35; 16% CP, 0.87% SID lysine, 2× CON industry-standard organic trace minerals and vitamins except selenium, plus 500 mg/kg vitamin C) fed from days 70 to 110 of gestation. All sows received a common lactation diet. Sow blood samples and body measurements were collected on days 70 and 110 of gestation, day 2 of lactation and at weaning (lactation day 19 ± 3). Piglets were weighed and tested for Hb at birth (n = 974) and weaning (n = 826). Serum was collected from 2 piglets per litter (n = 140) at 40–48 h after birth and at weaning. Serum was analyzed for copper, iron, zinc, ferritin, and 25(OH)D3. Whole blood was evaluated for red blood cell indices. Reproductive performance and blood markers were analyzed using PROC MIXED (SAS 9.4) with dietary treatment as a fixed effect and sow as a random effect. Farrowing duration was shorter in LGPHASE than CON sows (290.4 vs. 359.9 min; P = 0.028). Litter size and birth weight were similar between treatments, however, a reduced stillbirth rate tended to occur in LGPHASE sows (3.4% vs. 6.8%; P = 0.099). LGPHASE sows tended to wean more (13.4 vs. 12.3; P = 0.062) and lighter pigs (5.70 vs. 6.16 kg; P = 0.087) with increased piglet survivability (90.5% vs. 84.8%; P = 0.019). LGPHASE sows tended to have higher Hb at day 110 (11.2 vs. 10.7 g/dL; P = 0.091) and had higher Hb at weaning (10.7 vs. 9.9 g/dL; P = 0.004) than CON sows. At day 110, LGPHASE sows had greater serum 25(OH)D3 (54.8 vs. 35.5 ng/mL; P = 0.002), and tended to have greater serum ferritin at weaning than CON sows (38.5 vs. 28.3 ng/mL; P = 0.074). At day 2, LGPHASE piglets had greater serum ferritin (25.1 vs. 19.1 ng/mL; P = 0.079). At weaning, serum copper was greater in LGPHASE piglets (2.26 vs. 2.17 µg/mL; P = 0.022) and serum 25(OH)D3 tended to be greater than CON piglets (7.5 vs. 6.9 ng/mL; P = 0.080). In conclusion, late-gestation nutrient requirements exceed levels typically fed, with increased amino acid and micronutrient supply improving micronutrient status, shortening farrowing duration, and enhancing piglet viability, resulting in improved pre-weaning survival.