The metabolic status during the peri partum period affects the voluntary feed intake and the metabolism of the lactating multiparous sow

This trial was undertaken to investigate the metabolic changes occurring around farrowing and to assess their relationships with feed intake and metabolism of the sow during lactation. Twenty multiparous crossbred Landrace x Large White sows were catheterized at 70 days of gestation. Blood samples were collected at 37 +/- 2 days before farrowing (-37), daily during the week before (week -1, day -7 to day -1) and the week after farrowing (week +1, day +1 to day +7), and then at days 14 (+14) and 21 (+21) of lactation. At each stage, samples were drawn after an overnight fasting period just before (T0) and at 2 (T2) and 4 h (T4) after the morning meal. Feed intake of the sows averaged 6.3 +/- 0.3, 8.4 +/- 0.3 and 8.5 +/- 0.4 kg/day during the first, second and third weeks after farrowing, respectively. Backfat thickness, BW and energy balance did not vary during lactation. Glucose concentration increased progressively before farrowing for T0, T2 and T4 (P<0.05) while insulin concentration remained constant. Plasma concentrations of cortisol and NEFA at TO increased within the week -1 (P<0.05). The feed intake of the sows during the week +1 (r(2) = -0.42; P = 0.07), the week +2 (r(2) = -0.57; P = 0.01) and the week +3 (r(2) = -0.64; P = 0.004) was negatively correlated with the insulin-to-glucose ratio at T4 during the week -1. Feed intake during the week +2 (r(2) = -0.53; P = 0.02) and the week +3 (r(2) = -0.55; P = 0.02) was negatively correlated with the average leptin concentration during gestation. Energy balance during the week +1 was negatively correlated with insulin at T0 during the week -1 (r(2) = -0.53; P = 0.02). Cortisol concentration at day -37 was positively correlated with the NEFA concentrations at T4 during the week -1 (r(2) = 0.71; P<0.001) and tended to be negatively correlated with the energy balance during the week +1 (r(2) = -0.43; P = 0.07) and the week +2 (r(2) = -0.44; P = 0.06). Our results suggest that the sows with the lower feed intake and the most negative energy balance in early lactation mobilize already their body reserves during gestation. This could be related to an increased insulin resistance during late gestation but remains to be investigated using specific tests for the evaluation of insulin resistance. (C) 2009 Elsevier B.V. All rights reserved.