Brachyspira species detected by culture. (A) Culture results for each production stage at Site 1 (upper tier) and Site 2 (lower tier). The total number of samples tested is indicated in the centre of each chart. Culture negative samples are grey. (B) Abundance of different Brachyspira species detected among culture positive samples at Site 1 and Site 2. Identification of isolates was based on partial nox gene sequence and phylogenetic analysis.