From farm to slaughter: integrating welfare, pre-slaughter logistics and health data to explain carcass outcomes in commercial pigs.

Carcass traits such as slaughter weight, lean meat percentage, and meat colour are key determinants of profitability and consumer acceptance in pork production. This study integrated on-farm welfare assessments, management routines, preslaughter conditions, and health findings at slaughter to evaluate their combined effects on carcass outcomes in Norwegian pig herds. Data from 8 473 pigs were analysed using mixed models. The mean slaughter weight was 83.0 ± 0.1 kg, lean meat percentage 60.4 ± 0.0%, and meat colour score 48.2 ± 0.1 on the GP7 optical-probe scale, on which higher values indicate darker meat. Slaughter weight decreased with longer transport duration (P < 0.0001), overnight housing (P = 0.012), and health issues including joint inflammation (P < 0.0001), pneumonia (P = 0.037), liver parasites (P = 0.019), and open tail wounds (P = 0.023). Lean meat percentage was reduced by joint inflammation (P = 0.005) and shortened tails (P = 0.027). Meat colour increased with ear lesions (P < 0.0001), body lesions (P = 0.003), longer transport (P < 0.0001), overnight housing (P < 0.0001), chopped straw (P = 0.008), and open tail wounds (P = 0.003). Heavier pigs had darker meat (r = -0.056, P < 0.0001) and lower lean yield (r = -0.253, P < 0.0001). Application of the Critical Path Method identified transport-service confirmation, logistical and financial evaluation, loading, the maximum observed transport duration, and lairage as the stages that governed the total duration of the preslaughter process (151.6 h, with no temporal slack), where delays most prolong the time before slaughter. These findings highlight that welfare indicators, health conditions, and preslaughter handling jointly determine carcass value, linking animal welfare with economic returns and product quality in high-welfare production systems.