Response of the Iberian sow to protein supply and feeding level during late gestation

Abstract One hundred and twenty purebred Iberian (IB) sows in their second or third parity were used in two consecutive trials to determine the effects of dietary crude protein (CP) concentration and feeding level (FL) during late gestation on sow and litter performance. The sows were kept in groups in open-air, fenced spaces and randomly assigned from day (d) 70 of gestation to one of four experimental treatments in a 2 × 2 factorial arrangement with 2 CP levels (120 and 101 g CP/kg diet) and 2 FL (2.33 and 2.67 kg/d; metabolizable energy (ME) content, 12.50 MJ/kg diet). Nearing farrowing the sows were housed individually and fed a lactation diet (148 g CP/kg; 4.5 kg/d) for a 35-d lactation period. Piglets had no access to any feed. Body weight (BW) gain from d 70 of gestation to farrowing increased with FL (23.8 ± 0.88 vs. 27.3 ± 0.86 kg; P   0.05). The dietary factors did not affect plasma metabolite levels in late gestation, except plasmatic urea which decreased in third-parity sows with FL. In lactation, plasma urea level increased with CP (P