Can the way pigs are handled alter behavioural and physiological measures of affective state?

Research on human-animal relationship in animal production has been mainly focused on its effect on stress, productivity and meat quality. Only few studies have assessed its effects on the animals' affective state. In the present study, the influence of positive and negative handling (pH and NH, respectively) on affective state and fear as assessed by the cognitive bias test, the novel object test and the defence cascade test was studied in 56 pigs. Serum, saliva and hair were sampled during the study for the analysis of cortisol concentration. Results showed no differences between pH and NH pigs in the behavioural tests, which may be either due to the lack of previous handling effect on the test results, the lack of validity or the low sensitivity of these tests or a combination of them. Moreover, no differences were found in cortisol concentrations between handling groups. However, correlations between tests were found (p<0.05) suggesting that there are individual factors such as the fear level, the motivation or the coping style, that have a similar effect on the response to these tests. Moreover, pigs who were more fearful had higher (r=0.37; p=0.014) levels of serum cortisol at slaughter.