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

Abstract

Comfort Class offers each 110kg growing–finishing pig housed at 2.4m² with bedding in groups of 12 premium welfare to meet their behavioural needs. Conventionally housed, growing–finishing pigs in the Netherlands are allowed 0.8m², based on 0.035×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 3×2 factorial trial was designed to compare pigs housed at 2.4m², 1.6m² or 1.2m² per pig in pens of 29 and 58m². 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 1.2m² per animal would be lying in the kennels for 62%, 54% and 48% of the time (P<0.001) respectively and pigs housed at 2.4m² spent more time eating than those housed at 1.2m² (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 1.6m² tended to have less skin lesions on their hinds than those housed at 1.2m² per pig. Daily weight gain was higher in the small than the large pens (823 vs. 797g/d, P=0.003) and higher at 2.4 and 1.6m² than 1.2m² (827 and 817 vs. 786g/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.