The geographical extent of culling: wide area culling or on a risk-assessed basis

animals. The use of free bullets inside buildings or farmyards is rarely acceptable. If this is required, it must be carried out by very specialist marksmen and with special permission from appropriate authorities.

Where animals are to be brought together for killing by captive bolt pistols, adequate handling facilities are required for the numbers and types of animals to be killed. Barriers and crush systems that might be adequate for sheep or regularly-handled dairy cattle will be completely inadequate for rarely-handled adult beef cattle and there will be a risk of escape and injury to operators.

Killing large commercial pig herds or poultry flocks is not easy and requires careful planning. It is strongly recommended that culling and disposal plans for large units be discussed with owners of such units as part of the preparation and planning process rather than waiting until the outbreak has occurred. Depending on the method chosen for culling, it may be necessary to involve others in this process (e.g. suppliers of carbon dioxide if poultry flocks are to be killed through this method).

the geograPhIcal extent of cullIng: wIde area cullIng or on a rIsk-assessed basIs

It is important to emphasize that “eliminate it quickly” does not refer to, imply or require widespread culling of livestock. Culling of animals or groups of animals should be limited to those that are found to be actively infected, and in some situations, those at locations that have been found to be at high risk of having been infected through a veterinary risk assessment. There is rarely, if ever, a place for wide-area culling based purely on geographical location such as ring culls. It has been used in some situations, but there is little evidence that it was necessary and there is certainly evidence that control is achieved as effectively when contacts and geographical aspects are promptly assessed, based on risk.

Additionally, while it is easy to explain the principle of wide-area culls to policy-makers and relatively easy to then identify the premises where livestock are to be culled, it has the disadvantages of requiring more resources and time to complete than risk-based targeted

TABLe 2

advantages and disadvantages of wide-area and targeted culling

wide-area culling targeted culling

advantages Simple to define the area to be culled easy to explain to policy-makers Feeling of security Can be explained to owners Compliance encouraged Lower socio-economic impact Lower level of resources required

disadvantages Hard to explain to owners Discourages reporting encourages dispersion and concealment of animals High socio-economic impact Requires a high level of resources for culling Requires good information Can be more complex to organize