Feeding a nutrient enriched diet to late gestating sows across consecutive cycles improves micronutrient status, farrowing duration, and prolificacy

This study evaluated effects of a nutrient-enriched late gestation diet (LGPHASE) on reproductive performance and blood-based biomarkers in sows and their progeny through weaning. Seventy sows (parity 0–5) at 70 ± 2 d gestation were assigned to a control (CON; n = 35; 11% CP, 0.52% SID lysine, industry-standard organic trace minerals, and vitamins) or a 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. Blood was collected from sows at day 70 ± 2, day 110 ± 2, and weaning (lactation day 19 ± 3) for blood counts and serum analysis. Piglet Hb was measured at birth (CON: n = 479; LGPHASE: n = 495) and at weaning (CON: n = 395; LGPHASE: n = 431), and serum was collected from 2 piglets per litter (n = 70 per treatment) at 40–48 h post farrow and weaning. Sow and piglet serum was analyzed for copper, iron, zinc, ferritin, and 25(OH)D3. 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 in the LGPHASE piglets than CON piglets (7.5 vs. 6.9 ng/mL; P = 0.080). In the subsequent cycle, LGPHASE sows had more total born (19.24 vs. 16.84; P = 0.041) and live born pigs (17.70 vs. 15.00; P = 0.015), reflecting increases of 2.74 total born (P = 0.024) and 2.50 live born pigs (P = 0.031) from the prior cycle. Late-gestation nutrient needs exceed typical feeding levels; phase feeding improved micronutrient status, farrowing duration, piglet survival, and subsequent litter size.