Effect of outdoor pig production on the seroprevalence of Mycoplasma hyopneumoniae and lung lesions.

摘要

A study to determine the effect of outdoor production on the seroprevalence of M. hyopneumoniae and lung lesions in pigs is described. The study took place on a large 2500-sow production unit in Switzerland in June-November 2004. This unit had suffered from low production levels due to M. hyopneumoniae and Pasteurella multocida. 22 pregnant and M. hyopneumoniae-seropositive sows were selected for the study. Their piglets were raised indoors (n=101) or outdoors (n=100) according to procedures in the farm and were monitored for antibodies to M. hyopneumoniae until slaughter. The lungs were examined for gross lesions consistent with enzootic pneumonia (EP). It was shown that significantly more (P<0.01) lung lesions were present in pigs raised indoors. M. hyopneumoniae antibody titres were positively correlated (P<0.05) with the severity of lung lesions at slaughter. There were no significant differences between the antibody titres of pigs raised indoors or outdoors, at weaning and at 4 and 8 weeks after weaning. However, the pigs raised outdoors had significantly lower optical densities (ODs) at 12 weeks postweaning compared with those raised indoors. The differences in OD between groups was significantly different at 16 and 20 weeks of age. These results indicate that using outdoor production systems might be a management tool in the prevention of economic losses due to EP..