Risk assessment of PSE condition due to pre-slaughter conditions and RYR1 gene in pigs

A polychotomous logistic regression model was used to identify and assess the risk factors for pork meat becoming pale, soft and exudative (PSE). A total of 116 deliveries, comprising 15,695 commercial pigs delivered from different commercial farms to five Spanish pig commercial abattoirs were surveyed. The PSE condition was described as an ordinal response variable (normal, prone to PSE and PSE) based on measurements of electrical conductivity in the Semimembranosus muscle 1-2 h post-mortem. The RYR1 genotype, the abattoir, the season, the gender, the floor surface in the lorry, the loading system, and the stocking density during transportation influenced the risk of PSE condition, as well as on-farm fasting time, loading time, transportation and lairage times. The effect of the RYR1 gene, determined in a subsample of 1331 pigs, was due to nn stress-susceptible pigs, in which the risk of PSE meat (PQM>6 μs) increased fourfold. Abattoirs should be especially careful in summer, when the risk of PSE meat was found to be double that of winter. The risk of PSE meat decreased with the time of transportation, though its effect depended on the stocking density. Thus, our results indicate that, for transits longer than 3 h, the risk of PSE increases with stocking density during transport, while the opposite occurs for shorter transits.