COMPARATIVE EVALUATION OF THE EFFICACY OF SEVERAL COMMERCIAL Mycoplasma hyopneumoniae VACCINES UNDER FIELD CONDITIONS

摘要

The objective of this study was to determine lung lesions observed at slaughter in pigs vaccinated with either M+PAC~R (Schering-Plough Animal Health, Corp.) or other commercial M. hyopneumoniae (Mh) vaccines or unvaccinated controls. All data was obtained from Spanish farms and collected between 2001 and 2007. Farms were selected that were using 1) either single- or double- dose programs and 2) one of 4 different Mh vaccines. Farms were also selected that chose not to vaccinate for Mh. Lung lesion evaluations of individual batches of slaughter pigs were requested by the farmers. The scoring method used values ranging from 0 to 5, with 0 meaning no lesions and the 1 to 5 scores indicating increasing levels of lung lesions. 73.1 % of the scorings were blind as to the vaccine used in the evaluated pigs. For analysis, all the lung lesion scores were combined by treatment and each treatment comprised a group. The following statistical methods were used: Pearson Chi squared test with continuity correction, Mann-Whitney U and Wilcoxon W.