Changes in Carcass Composition, Meat Quality Traits, and Stress Levels in Culled Sows Exposed to Different On-Farm Rest Periods

The study investigated the effect of on-farm rest period (RP) on carcass composition, meat quality, and stress indicators of culled sows. The study was conducted on 84 Large White x Landrace culled sows, which were divided into seven groups (n = 12) with respect to the duration of the on-farm rest period: no rest period (N-RP) group and 1 to 6 weeks of on-farm rest period (1-6 RP). After completion of the on-farm RP, each group of culled sows was slaughtered and the carcass and meat quality traits were determined. Sows from 6-RP had a significantly higher dressing percentage and backfat thickness and, together with sows from 5-RP, a higher shoulder weight. The highest shoulder percentage was found in the 3-RP and 4-RP groups, while 1-RP had the highest percentage for the belly-rib part. At the same time, RP influenced the final pH values (pH(24) SM and pH(24) LL) measured in the longissimus thoracis et lumborum (LT) and in the musculus semimembranosus (SM), as well as drip loss, thawing loss, cooking loss, and tenderness. As far as the stress indicators are concerned, statistical differences between groups were only found in the cortisol level, which was lowest in 6-RP. The results show that RP has a positive effect on meat quality traits and carcass composition. In addition, prolonged RP has a positive effect on the levels of stress indicators.