This study was determined to assess the difference between a one-shot and a two-shot-vaccination
against Mycoplasma hyopneumoniae, the pathogen of Enzootie Pneumonia in pigs. The assessment was
effected by abattoir surveillance of the lungs of 356 pigs, of whom 185 had received the one-shot vaccine
Stellamune One (Pfizer) in the first week and 171 had received the two-shot vaccine Stellamune
Mycoplasma (Pfizer) in the first and fourth week by the livestock owner. Neither the one-shot- nor the
two-shot-vaccination caused any kind of discomfort or complication to the animals. Before the start of the project, the health status of the farm was assessed by serological testing of ten randomly selected pigs
and by abattoir surveillance of 141 pigs. The health status proved favourable, even though M.
hyopneumoniae was detected in all diagnostic assays. Additional assessment of secondary bacterial and
viral agents was performed: PRRSV was isolated in only a few cases and APP only in one case.Because of
the low weight and the relatively high age of the pigs at slaughter there is reason to believe that the
infection with M. hyopneumoniae takes place early in the farrowing period. The results of the abattoir
surveillance did not generate any statistically significant difference between the two types of
vaccination. However, a trend towards decrease in lung lesions can be detected in the one-shotvaccination.
Regarding pneumonia lesions of the cranial lobe, the two-shot-vaccination tends to evolve
better results. An additional comparison of seasonal groups of pigs showed no significant difference
regarding the gravity of lung lesions. In conclusion it can be stated that there is no difference in a weil
managed farm (from farrow-to finish production system, all-in-all-out, no introduction of foreign
animals) with good health status concerning the use of a one-shot- or a two-shot-vaccination. A
thorough surveillance of the pigs regarding the onset of coughing or respiratory discomfort and the
compilation of a serological profile would be desirable in order to determine the time of infection.