Optimal lairage times and conditions for slaughter pigs: a review

Keeping pigs in lairage provides a buffer to supply the slaughter line and allows the pigs to recover from the stress of transport. It has implications for the pigs' welfare by influencing their behaviour and ease of handling. In terms of pork quality, optimal lairage times for most pigs in the UK are probably one to three hours. Shorter lairage times are associated with more pale, soft, exudative (PSE) meat and longer times are associated with more dark, firm, dry (DFD) meat, more skin blemishes caused by fighting, and a lower carcase yield. However, when pigs have not been previously stressed by handling procedures, resting them in lairage may have no beneficial effects on the pigs' welfare or meat quality. At very high environmental temperatures there is evidence that a holding period of less than one hour may help to reduce the number of PSE carcases. At temperatures above 10 degrees C showering the pigs with water is beneficial. Fasting times need to be controlled to minimise the potential loss of carcase yield while reducing the volume of gut contents to reduce the risk of carcase contamination. Lairages can act as reservoirs of infection by pathogenic bacteria and there is evidence that longer holding times increase the risk of cross-contamination.