The pathway for change in herd classification, based on McGuin (1986) and the final (1995) version of the standard definitions and rules (Box 1). The pathway for change in herd classification, based on McGuin (1986) and the final (1995) version of the standard definitions and rules (Box 1). This figure represents the status pathway used during BTEC and should not be strictly interpreted as a hierarchy of risk. For example, depending on herd history, MN status was generally (but not always) considered to represent a lower TB risk than CF S. J. More et al. Veterinary Record 2015;177:224-232 Copyright © British Veterinary Association. All rights reserved.