Risk assessment of skin damage due to pre-slaughter conditions and RYR1 gene in pigs.

A polychotomous logistic regression was used to assess the risk factors for skin damage prior to slaughter. A total of 116 deliveries (15,695 pigs) from commercial farms to five Spanish pig abattoirs were surveyed. The skin damage condition was described as an ordinal response (1: no damage; 2: very slight damage; and 3: slight or more damage). The abattoir by the season (p<0.01), the floor surface of the lorry (p=0.02), and the mixing of unfamiliar pigs at loading (p=0.01) influenced the occurrence of skin blemishes. Skin damage increased with on-farm fasting time (p<0.01), loading time (p<0.01), lairage time (p<0.01), as well as with carcass weight (p<0.01). In winter transports the risk of skin damage decreased (p<0.01) at higher space allowance in the lorry. The risk of developing PSE and DFD pork increased with the skin damage score (p<0.01). The nn genotype for the RYR1 gene was less prone to skin damage but at the same time it is more sensitive to skin damage in relation to PSE risk. It is concluded that the skin damage score can be used as a rapid indicator of animal welfare and pork quality.