Funder and dates: SRUC, 2016-2019
Aggression at regrouping is experienced by most commercial pigs and has negative effects on welfare, growth, reproductive performance and immunocompetence. It has been actively researched since 1970 but persists undiminished as a routine challenge to welfare despite the factors affecting aggression largely being known. This is partly due to the difficulty in applying suggested methods to reduce aggression, e.g. the need for building modification or increased labour input. Moreover, practicing farmers may be desensitised to aggression due to its routine occurrence. This is likely to constrain effort to control it irrespective of associated costs and benefits. The overall aim of the project is to identify current and new strategies to control aggression that are acceptable and financially suitable for a wide range of pig farmers and to communicate these strategies to commercial practice. In the first phase of the work, farmers’ perception of aggression will be assessed by their rating of perceived severity of aggressive interactions. These ratings will be compared against objective metrics of exertion and injury for the same pigs from the same aggressive interactions. This will be followed in the second phase by use of a choice experiment to quantify farmers’ willingness to trade-off a specified reduction in aggression against other non-welfare related priorities. This should result in the determination of the bounds of management change likely to be acceptable to farmers. In the final part of the work, a cost-effectiveness analysis of mitigation strategies to reduce aggression will be performed. Management strategies will then be ranked and evaluated based on their cost-effectiveness ratios in the short- and long-term. Based on the outcomes of the three phases of work, mitigation strategies will be shortlisted that are likely to achieve acceptable combinations or trade-offs between the control of aggression and other goals for business.