Influence of alternative semi-outdoor housing systems in comparison with the conventional indoor housing on carcass composition and meat and fat quality of finishing pigs | Comparaison de systemes de detentions avec courette et de systemes conventionnels pour porcs a engrais: influence sur la composition de la carcasse et la qualite de la viande et du tissu adipeux

A survey was carried out during the years 2000 to 2001 in Switzerland to investigate the influence of two housing systems, the conventional housing system (CON) and alternative housing systems (ALT), on three quality criteria of fattening pigs: fat score, fat-free lean percentage, and pH course of the M.l.d. postmortem. The CON comprised fully-slatted floors with minimal legal pen size (0.45 to 0.65 m2 per growing-finishing pig) whereas ALT referred to an advanced animal welfare housing system with more space (0.60 to 0.90.m2 per growing-finishing pig), a multi-surfaced floor including a feeding place (sometimes perforated), a non-perforated littered rest area, and a limited permanent accessible outdoor area (0.45 to 0.65 m² per pig in addition to the indoor surface). The farms were further classified into two different feeding systems, the whey- (=liquidin CON mainly cheese dairies) and complete feeding system. The study plan was a split-plot design where the effect farm was considered as a random class effect nested in the fixed effects housing and feeding system. Observations (pH-measurements) from a summer (2000) and a winter (2000/2001) fattening period were carried out in two major Swiss slaughterhouses with CO2 stunning, which kindly provided the carcass data of the monitored pigs (fat score, fat-free lean, and slaughter weight). The pigs (usually 20 to 30 per farm and fattening period) previewed for monitoring were raised and fed as the others in the farms but kept in separate pens. Feed samples of the entire fattening period were collected and analysed (Weender analysis and gas-chromatographic fatty acid profile). The farmers usually practised a split marketing according the weight of the animals of 1 to 3 market groups per fattening period. The experimental unit of the criterion fat score was market group, whereas records of individual pigs made up the experimental unit for the criteria fat-free lean and pH. Several covariates (given below) were regarded in the linear mixed effects models adjusting the ls-means. The unbalanced data set was analysed with the computer package of SAS, 8.02 release, PROC MIXED, using the Restricted Maximum Likelihood (REML) approach (…).