Relationships between selected climatic factors in fattening units and their influence on the development of respiratory diseases in swine.

The correlation between climatic parameters with one another in fattening units and the influence of environmental factors on lung lesions registered at slaughter were studied in 6 integrated herds with continuous production systems. In addition, the influence of environmental parameters on the spread of Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae (serotypes 2 and 3) and on the productivity was monitored in 2 specialized fattening herds with strict batch production. The outdoor temperature was positively correlated to the indoor temperature, but negatively correlated to the relative humidity and the concentration of carbon dioxide in the stables. These indoor parameters were also correlated to each other. The concentration of ammonia was not correlated to any other climatic parameter. No correlation between the climatic parameters measured and the prevalences of pneumonia and pleuritis registered at slaughter was shown. The rapidness in spread of mycoplasmosis seemed to be more dependent of the antibody status of the pigs on arrival than on the climate of the units. In contrast, a correlation between the climatic parameters and the spread of the less contagious infection (Actinobacillus) was indicated. The influence of the climatic parameters on the daily weight gain was not ensured.