A survey of mortality in slaughter pigs during transport and lairage.

Of 2.9 million pigs transported to seven slaughter plants in 1991 and 1992, 1781 (0.061 per cent) died in transit and 314 (0.011 per cent) died subsequently in the lairage. Overall mortality for both years was 0.072 per cent and mortality in 1992 was 0.066 per cent. There was little seasonal variation in the number of pigs dying in lairage, but more pigs died in transit in months when the weather was hotter. The relationship with temperature was curvilinear; above about 15 to 17 degrees C the detrimental effect of high temperatures was far more serious. In 1992, the year for which complete data were available, average mortality in the seven plants ranged from 0.045 to 0.093 per cent, but this variation was not related to the size of the plant. The number of pigs which died in lairage, rather than in transit, ranged from 4 to 21 per cent of all deaths in the different plants, and the average was 15 per cent. The variation might be related to differences in average lairage times or to the policies of individual plants with regard to moribund pigs. The survey provided no evidence that the mortality among transported pigs has increased over the last 20 years.