Dynamics of verotoxin-producing Escherichia coli isolated from German beef cattle between birth and slaughter

The critical duration for the shedding period above which the VTEC could propagate themselves on the farms by f.e. transmission between animals was found to be between 8 and 18 sampling intervals of 28 days (224-504 days) for ECvt1,2, and between 5 and 6 sampling periods of 28 days each (140-168 days) for the pVTEC which is smaller than all critical shedding periods for ECvt1,2. The reasons for ECvt1,2 being isolated from faeces earlier than pVTEC are discussed.