Space allowance and pen size affect welfare indicators and performance of growing pigs under Comfort Class conditions

Comfort Class offers each 110 kg growing-finishing pig housed at 2.4 m(2) with bedding in groups of 12 premium welfare to meet their behavioural needs. Conventionally housed, growing-finishing pigs in the Netherlands are allowed 0.8 m(2), based on 0.035 x BW0.667. The extra space offered with Comfort Class is a major financial barrier to introduce this system in practice. In order to establish whether or not welfare and performance could be maintained whilst reducing space allowance, a 3 x 2 factorial trial was designed to compare pigs housed at 2.4 m(2), 1.6 m(2) or 1.2 m(2) per pig in pens of 29 and 58 m(2). Video recordings, skin and tail lesions, lameness scores and performance were collected during three replicates involving 216 pigs each. Results indicate that pigs housed at 2.4, 1.6 or 1.2 m(2) per animal would be lying in the kennels for 62%, 54% and 48% of the time (P<0.001) respectively and pigs housed at 2.4 m(2) spent more time eating than those housed at 1.2 m(2) (4.7% and 4.4% of the time respectively, P < 0.05). Pigs housed in the small pens spent less time in the kennel and more time rooting than those in the large pens (53.0% vs. 55.8% in kennel, P=0.046; 1.78% vs. 1.22% rooting, P < 0.001). Pigs housed in the small pens had less tail lesions and those housed at 2.4 and 1.6 m(2) tended to have less skin lesions on their hinds than those housed at 1.2 m(2) per pig. Daily weight gain was higher in the small than the large pens (823 vs. 797 g/d, P=0.003) and higher at 2.4 and 1.6 m(2) than 12 m(2) (827 and 817 vs. 786 g/d, P=0.002). Overall, an increase in group size and stocking density both had unfavourable effects on welfare and performance, even at these high space allowances. However, performance benefits from higher space allowances did not compensate for increases in housing costs. (C) 2013 Elsevier B.V. All rights reserved.