The effects of precisely meeting estimated daily energy and lysine requirements for gestating sows over three consecutive pregnancies on sow reproductive and lactation performance

The objective of the current study was to determine the effects of precisely meeting estimated daily energy and Lys requirements for gestating sows over three consecutive pregnancies on sow reproductive and lactation performance. A total of 105 sows (initial reproductive cycle 1.4 ± 0.5) were randomly assigned to a precision (PF; n = 50) or control (CON; n = 55) feeding program between days 2 and 9 of gestation and housed in group-pens equipped with electronic sow feeders capable of blending two diets. The PF sows received unique daily blends of two isocaloric diets (2518 kcal/kg NE; 0.80% and 0.20% standardized ileal digestible [SID] Lys, respectively), whereas CON sows received a static blend throughout gestation to achieve 0.56% SID Lys. After weaning, sows were re-bred and entered the same feeding program as in the previous pregnancy for two subsequent pregnancy cycles (PF: n = 36; CON: n = 37; average reproductive cycle: 2.4 ± 0.5; PF: n = 25; CON: n = 24; average reproductive cycle: 3.5 ± 0.5). Sows on the PF program received 97%, 105%, and 118% (average over three pregnancy cycles) of dietary energy and 67%, 79%, and 106% of SID Lys intakes compared to CON between days 5 and 37, 38 and 72, and 73 and 108 of gestation, respectively. Estimated N (26.1%) retention did not differ between gestation feeding programs in any pregnancy, but excess N excretion was less (1617 vs. 1750 ± 54 g/sow; P < 0.01) for PF vs. CON sows. Regardless of pregnancy cycle, sows that received the PF program had greater ADG between days 38 and 72 (614 vs. 518 ± 63 g/d; P < 0.05) and between days 73 and 108 (719 vs. 618 ± 94 g/d; P = 0.063) of gestation, and greater loin depth gain between days 63 and 110 of gestation (0.7 vs. −1.1 ± 1.6 mm; P < 0.05), but BW (235.1 kg) and backfat (17.8 mm) and loin (70.5 mm) depths on day 110 of gestation did not differ. The number of piglets born alive, stillborn, and mummified, and litter birth weight (16.5 kg) did not differ in any pregnancy cycle, nor did piglet ADG during lactation (250 g/d) and piglet BW (6.7 kg) at weaning. Sows that received the PF program during gestation had lower ADFI during lactation (5.7 vs. 6.2 ± 0.2 kg; P < 0.01). Therefore, using feeding programs that precisely match estimated daily energy and Lys requirements for gestating sows provides the opportunity to reduce N losses to the environment and reduce lactation feed usage, without negatively affecting sow reproductive and lactation performance.