Meat Science, 2018, 142, 38-43
Cortisol and corticosterone in saliva were evaluated as pig stress biomarkers, using pig genotype (Duroc, L62 or Pietrain) and lairage time in the slaughterhouse (0, 2.0, 4.0 or 6.0 h) as controlled variables. Although some pigs were found to be carriers of stress susceptibility, all were healthy heterozygous individuals. Pre-slaughter transport increased cortisol levels in saliva above 3.0 μg/L (medium stress), and 4.0 h of lairage in the slaughterhouse raised them above 6.0 μg/L, whereas corticosterone concentrations exceeded 4 μg/L, which are suggestive of high stress. The highest cortisol levels were detected in the Duroc genotype. Other factors such as food deprivation, background noise, the presence of a large number of animals waiting to be slaughtered, mixing with unfamiliar animals or recent mixing of genders may also influence stress. Corticosterone proved a reliable indicator of high stress only. Meat quality from the pig breeds studied was not affected by lairage in the slaughterhouse for up to 6.0 h.