Growth performance and carcass characteristics of two genotypes of growing-finishing pig in three different housing systems

Abstract

AbstractA trial was conducted to compare the growth performance and carcass characteristics of 720 growing pigs housed in one of three different finishing systems: outdoor paddocks, straw yards and fully slatted pens. Two genotypes were used: ‘indoor’ (progeny of Large White ✕ Landrace sows mated to Large White boars) or ‘outdoor’ (progeny of part-Duroc or part-Meishan sows, mated to Large White boars). Groups of 20 pigs were reared from an average of 30 to 80 kg live weight and given ad libitum access to a commercial specification diet. The outdoor genotypes had significantly lower average daily gain than the indoor genotype (682, 673 and 719 g respectively for part-Duroc, part-Meishan and indoor-type pigs, P 0·01). Part-Meishan genotypes had significantly higher backfat levels than the indoor genotype (P 0·05), with an intermediate value for part-Duroc pigs (22·6, 21·1 and 21·8 mm respectively). Values for food conversion ratio were significantly higher for combined outdoor genotype groups when compared with the indoor genotype (2·76 v. jt>2·62, P 0·05). Average daily gains of pigs in straw yards and outdoor paddocks were significantly higher than for those in fully slatted pens (736 and 675 v. 627 g, P 0·01 respectively). Food conversion ratio was similar for pigs in outdoor paddocks and fully slatted pens, but significantly lower for those in straw yards (2·77 and 2·75 v. 2·55, P 0·01 respectively). Backfat depth (P1 + P3mm) was significantly greater for animals finished in straw yards compared to those in outdoor paddocks (22·2 v. 20·6 mm, P 0·05) and intermediate for those finished in fully slatted pens (21·5 mm). Interaction between finishing system and genotype did not occur to any major degree, hence it appears unnecessary to specify a particular genotype for a particular finishing system. It was concluded that pigs of the outdoor genotype had a lower growth performance compared with the indoor genotype. Finishing systems however may have been confounded by other factors so that no clear recommendations can be made as to the optimum finishing system.