Herd A | ||||||||

a (n=33) | b (n=33) | c (n=35) | d (n=31) | P value | a–c (NV; n=68) | b–d (V; n=64) | P* value | |

Prevalence of Mhyo-like lesions | 95.7^{A}
| 65.2^{B}
| 60.0^{B}
| 47.6^{B}
| 0.038 | 77.1^{A}
| 56.8^{B}
| 0.045 |

Prevalence of fissures | 33.3 | 17.4 | 0.0 | 0.0 | 0.676 | 16.3 | 9.1 | 0.360 |

LLS | 29.4±19.1^{A}
| 14.9±16.7^{B}
| 23.6±28.6^{AB}
| 16.1±21.8^{B}
| 0.032 | 26.4±24.4^{A}
| 15.5±19.1^{B}
| 0.021 |

Herd B | ||||||||

a (n=47) | b (n=55) | c | d | P value | a–c (NV; n=47) | b–d (V; n=55) | P* value | |

Prevalence of Mhyo-like lesions | 78.7 | 74.1 | N/A† | N/A† | N/A† | 78.7 | 74.1 | 0.649 |

Prevalence of fissures | 46.8 | 37.9 | N/A† | N/A† | N/A† | 46.8 | 37.9 | 0.428 |

LLS | 8.4±8.5 | 9.7±11.6 | N/A† | N/A† | N/A† | 8.4±8.5 | 9.7±11.6 | 0.541 |

Vaccination status: NV (pigs originating from non-vaccinated sow farrowing batches) and V (pigs originating from vaccinated sow farrowing batches). The P value refers to the comparisons between the individual farrowing batches, and the P* value to the comparisons between the summaries of the NV (a–c) and V (b–d) batches. Values with different superscripts within a row are significantly different (P<0.05 and P*<0.05).

†Non-applicable as pigs of batches c and d were slaughtered before the pre-arranged time and thus, no lung lesion evaluation was performed.