Comparing farmers’ perceptions of the severity of pig aggression seen in video clips against actual severity.

The uptake of animal welfare research in commercial practice is highly dependent upon whether the farmer perceives it as a problem that needs to be addressed. Our objective is to assess farmer perceptions of the longstanging animal welfare issue of aggression between pigs. Mixing unfamiliar pigs is common practice in pig husbandry creating high levels of aggression as dominance relationships are established. Aggression threatens pig welfare through exhaustion, injury and stress. These physical costs can also threaten farm productivity. A large body of literature exists and a number of management strategies to reduce aggression in intensive farming systems have been identified, however, few have been adopted in practice (1). A recent survey of 167 UK pig farmers revealed that the majority did not perceive aggression as a problem (2). We employ a novel method to investigate whether farmers underestimate the physical impact of the issue. Specifically, farmers were asked for their perception of aggression seen in video clips and their response is compared to actual measures of severity.
92 UK pig farmers were recruited at six seperate farmers’ group meetings. They viewed four 20 s video clips of pigs either during (clip 1) or immediately after (clips 2-3) a fight and answered a paper based survey employing visual analogue scales (VAS). Control groups of non-farmers with variable experience of working with pigs completed an amended version of the survey (35 agricultural students, 26 animal science students and 10 specialist pig veterinarians). Video footage was obtained from a seperate research project whereby 168 growing pigs were video recorded in aggressive dyadic encounters. For each pig measures of skin lesions and blood lactate were taken pre- and post-fight to indicate relative change as a result of aggression. Skin lesions indicate the severity of aggression and blood lactate gives a measure of physical fatigue. A stepwise selection process was adopted to choose each video clip. Based on the severity of skin lesions and blood lactate we identified from the entire dataset the encounters whereby both pigs obtained high (upper quartile), medium (interquartile range) or low (lower quartile) severity measures. In each meeting the clips were displayed in a different order. Clip 1 was always first and acted as a practice and a common start point, but was not for analysis. Following each clip, farmers were asked to place a downward line through each of the 100mm VAS at a point they felt best represented: i) how much of a negative emotional reaction they had; ii) how exhausting they believe the fight was; and iii) how severe they believe the fight was. Results are curently under analysis and will be presented at the conference. Farmers’ scores will be compared against the scores of the control groups and the scores of all groups will be compared against the objective measures. Analysis will focus on whether farmers underestimate the physical impact of aggression. We will highlight the importance of understanding human behaviour in resolving animal welfare problems.