Influence of porcine housing density on species diversity and number of airborne microorganisms at fattening facilities

Primary microclimatic conditions were monitored in a fattening and finishing facility of 450 square m (equipped with 44 pens designed for 10 animals each) with low-pressure ventilation in order to determine the possible association of the number of pigs per unit of housing space with species diversity and number of airborne microorganisms. Three trials were conducted as follows: the first trial was conducted during the autumn-winter period with the capacity of 440 animals (0.7 square m of pen area per fattening pig), the second trial was conducted during the winter-spring period with 356 animals (0.8 square m of pen area per fattening pig), and the third trial was conducted during the spring-summer period with 312 animals (1.0 square m of pen area per fattening pig). According to the data obtained from all trials, the total number of bacteria and fungi did not exceed 10,000 and 1,000 CFU per cubic m, respectively. The most numerous were gram-positive bacteria, followed by gram-negative bacteria and fungi. The total number of airborne microorganisms correlated significantly with porcine housing density.