A qPCR based on Marois et al. (2010) was used to assess the number of M. hyopneumoniae organisms. Briefly, after DNA-extraction, qPCR was performed with primers 50
GTCAAAGTCAAAGTCAGCAAAC 30 and 50 AGCTGTTCAAATGCTTGTCC 30 using iQ SYBR Green Supermix (Bio-Rad, Eke Nazareth, Belgium) in the CFX96 real-time PCR detection system (Bio-Rad).