Reduction of transport-induced stress on finishing pigs by increasing lairage time at the slaughter house

Objective: Since pre-slaughter handling such as transport and lairage has been identified as one of the most stressful periods in the pig’s life, the main aim of this project was to determine if an increase in lairage time reduces stress markers when the animal transportation period is short. The effect of gender (gilts versus barrows) was also estimated. Materials and methods: A total of 200 pigs (129 gilts and 71 barrows) were subjected to two different lairage times at the slaughterhouse, short lairage (3 hours) and long lairage (12 hours), after a short journey (15 km, 20 minutes) by road from farm to abattoir. Blood samples were collected at the beginning of the slaughter line to determine stress markers: acute phase proteins (haptoglobin, serum amyloid A, and C-reactive protein) and neutrophil to lymphocyte (N:L) ratio. In the chilling tunnel, pH was measured in the semimembranosus muscle 45 minutes post mortem. Results: Our results showed that a longer lairage time allowed the pigs to recover from transport stress, indicated by a decrease in acute phase protein levels (haptoglobin, C-reactive protein), and N:L ratio. Sensitivity to stress did not differ between gilts and barrows. Implications: Under the conditions of this study, several stress indicators increase less when market gilts and barrows transported a short distance are allowed a longer lairage time (12 versus 3 hours). These stress indicators may be useful measures in research about transport welfare.