Collecting data at the slaughterhouse is a common method to obtain information on health and productive parameters, mainly from the last weeks of a pig’s life.
M. Sibila, J. Segalés, M. Pieters, L. Oliveira, D.G.D. Maes
Lung lesion evaluation is, by far, the information most frequently collected, basically to confirm and quantify respiratory problems, as well as to assess the outcome of certain intervention strategies. The two most prevalent pulmonary lesions observed at the pig slaughterhouse are:
In the present article, CVPC refers to purple-dark and well-defined areas of pulmonary consolidation, mainly located bilaterally in apical, intermediate, accessory as well as the cranial part of the diaphragmatic lung lobes (Figure 1).
In most cases, this type of lesion is associated to Mycoplasma hyopneumoniae (M. hyopneumoniae) infection. However, this lesion can be produced by other pathogens, such as swine influenza virus in a multifocal pattern, and Bordetella bronchiseptica and Pasteurella multocida in a more diffuse manner. Therefore, the causative agent(s) should be determined by means of laboratory techniques.
In acute M. hyopneumoniae disease cases (and without secondary infections), the lesion is clear and well-demarcated, being easily recognized and scored. However, in most cases, the lesion is aggravated with the presence of other bacterial or viral pathogens, varying in color, consistency, and extension (but not the craneo-ventral location).
At slaughterhouse, CVPC lesions tend to be chronic, the color tends to be greyish, and the tissue can be retracted forming scars or interlobular fissures, complicating its observation and scoring. If other lesions are present, such as pleuritis, the scoring from the affected lobes can even be more difficult or not possible to assess. Macroscopically the severity of CVPC is measured by its extension; the higher the percentage of affected tissue, the more severe the lesion.
Pleuritis refers to the inflammation of the pleural serosa. When this lesion is confined to dorso-caudal lobes, it is strongly suggestive of Actinobacillus pleuropneumoniae infection (Figure 2). Chronic cases (those usually present at slaughterhouse) are characterized by fibrous adhesions to visceral and parietal pleura. In such cases, lung tissue adhesions are common and leave part of the organ adhered to the thoracic wall during the lung’s removal from carcass, leading to its condemnation. In this scenario, presence of these lung adherences would be indicative of high severity.