Institut für Nutztierwissenschaften, ETH Zentrum, CH-8092 Zürich

Fattening pigs: influence of housing systems on the pH-value of the musculus long. dorsi (M.l.d)

In a survey, the effect of alternative (ALT) compared to conventional (KON) housing systems on the post mortem pH of the M.l.d. of fattening pigs was investigated. ALT housing systems corresponded to the Swiss BTS and RAUS regulations providing for e.g. larger and enriched pens with a straw bed as well as limited outdoor access. The pH was taken at 35 minutes, 2 and 24 hours post mortem. In general, the differences in mean scores for the pigs, which were classified into farm groups with the same feeding system, same season and same slaughterhouse, were few and mostly non-significant. A majority of ALT pig groups within a total of eight comparisons exhibited a numerically slightly higher pH at 35 minutes and 2 hours, whilst two comparisons were neutral and one ALT group exhibited a lower early-post mortem pH value. This could be explained by better adaptation (i.e. fewer stress symptoms) of ALT pigs to novel situations such as transport and lairage at the slaughterhouse. The pH at 24 hours did not show any significant differences. The frequency of PSE (pale, soft, exudative) meat was in general very low (<1 %), but was higher (3,8 %) when the sire line was a Piétrain breed. The rate of DFD (dark, firm, dry) meat was vanishing small. The impact of housing systems was generally low, and the results of this study suggest that ALT housing systems introduced in order to improve animal welfare in pig husbandry do not exert a negative impact on meat quality (as also shown previously for the criteria adipose tissue).

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