Relationship between the indicators of performance and the weight of pneumonic lesions from pigs at slaughter.

Lungs from pigs at slaughter were examined and the extent of the lesions was estimated as the percentage by weight of the lung affected by pneumonia in relation to the weight of the whole lung. Linear regression analyses of mean daily gain in liveweight and days to slaughter on the percentage by weight of pneumonic lung were performed. Within a range between 3.32 and 74.55 per cent for the weight of pneumonic lung, a 10 per cent increase in the weight of pneumonic lung was associated with a decrease in mean daily gain of 31.4 g and a 13.2-day increase to slaughter at 104.2 kg liveweight. When subgroups of pigs were evaluated by farm of origin, significant associations between indicators of performance and pneumonia for pigs from only one of the farms were found.