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Pre-slaughter handling has been identified as one of the most stressful periods in a pig’s life.The main aim of this project was to determine if an increase in lairage time (from 3 hours to 12 hours) improves stress markers (APPs, N:L ratio, and semimembranosus muscle pH) when the journey length is short (15 km). The gender effect (gilts versus barrows) was also investigated.
The experiment was conducted in Murcia (southeast area of Spain). When the pigs weighed approximately 100 kg, they were transported by road from the farm to the abattoir, a distance of approximately 15 km (approximately 20 minutes journey) in a truck with 0.42 m2 of space allocated per animal. The first group of animals, coming from one barn, were loaded at 6:00 am, arrived at the abattoir at 6:20 am, and had a lairage of 3 hours (treatment short lairage = 3 hours; SL). The second group, coming from the second barn, were loaded at 8:00 pm and had a lairage of 12 hours (treatment long lairage = 12 hours; LL).After the animals were stunned with CO2, blood samples were collected at the beginning of the slaughter line during exsanguination. The pH in the right semimembranosus muscle was measured in the chilling tunnel 45 minutes post mortem (pH45). The N:L ratio was determined for 30 animals per treatment (15 gilts and 15 barrows) randomly selected. Acute phase proteins were assayed in the same 30 animals per treatment (15 gilts and 15 barrows), including CRP, SAA, and Hp.
The effect of lairage time on Hp, CRP, and N:L ratio was significant. Median haptoglobin and CRP were more than twice as high after a short lairage, demonstrating that these proteins may indicate early stress. However, median SAA concentration did not differ significantly between SL and LL. The N:L ratio differed significantly by lairage, with a higher coefficient for SL. The pH45 of meat was significantly greater for SL than for LL.
A period in lairage allows animals to recover from the stress of previous handling, which is expected to improve meat quality. We found that 3 hours lairage was insufficient to fully acclimatize pigs, while 12 hours resulted in lower stress measurements. However, as this study did not test an intermediate time between 3 and 12 hours, future work is necessary to test intermediate lairage times.
García-Celdrán M, Ramis G, Quereda JJ, et al. Reduction of transport-induced stress on finishing pigs by increasing lairage time at the slaughter house. J Swine Health Prod. 2012;20(3):118-122.
