Influence of precision feeding of sows over three consecutive gestations adjusted for energy, amino acids and minerals on sow performances and a marker of bone resorption

Supplying only one type of diet to gestating sows does not sufficiently cover the variability in individual and daily requirements of sows throughout gestation. A cumulative mineral imbalance decreases the overall performance of a sow herd. Mineral deficiency is particularly critical during lactation, when mobilisation of bones occurs, and during gestation, when it should recover. Excess minerals influence environmental impacts and economic outcomes. The objective of this study was to assess the influence of a precision feeding (PF) strategy adjusted for energy, amino acids and P over three consecutive reproductive experimental cycles on sow productive performances, nutrient balances, health and mineral status. The PF strategy involved adjusting daily dietary supplies at the individual level based on quantity (energy) and quality, including amino acids (standardised ileal digestible lysine, SID-Lys) and minerals (apparent total tract digestibility of P, ATTD-P). Seven days after insemination, two batches of 28 Landrace × Large White gestating sows were allocated to one of the two feeding strategies (PF vs a standard feeding strategy with a single diet adjusted on energy requirements (SF)) based on their parity, BW and backfat thickness. The PF strategy consisted of mixing two iso-net energy (NE) diets (9.0 MJ/kg, 2.6 g/kg ATTD-P, with low: 3.3 g/kg or high: 8.5 g/kg SID-Lys content, respectively) in an automatic feeder on an individual and daily basis until day 80 of gestation. During the last month of gestation, an additional diet (4.0 g/kg ATTD-P) was supplied to ensure that the sows' increased P requirements were met. In contrast, SF sows were supplied only one diet throughout gestation (9.0 MJ/kg NE, 2.6 g/kg ATTD-P and 4.7 g/kg SID-Lys). The SID-Lys intake over three consecutive gestations was 18% (P < 0.001) lower for PF than SF sows without decreasing farrowing performances (P > 0.10). PF reduced feed cost up to 5 €/tonne (P < 0.001). Only during the last week of gestation, daily ATTD-P intake was 1.5 g greater for PF sows than for SF sows (P < 0.001). The feeding strategy did not influence total ATTD-P intake or urinary concentration of C-terminal telopeptide of type I collagen, a bone resorption marker (P > 0.10). Adjusting P supplies to the sows' P requirements only during the last month of gestation better met their nutritional needs, had no long-term effects on farrowing performances and did not decrease bone resorption compared to the SF strategy adjusted for energy.