Welfare assessment in 82 pig farms: effect of animal age and floor type on behaviour and injuries in fattening pigs

A welfare assessment method was built based on criteria related to behaviour, lesion scores and human/animal interactions, and tested thereafter in two main types of forms differing by their type of floor. either concrete, fully or partially slatted (C; n = 42) or straw bedding (S; n = 40). Observations were carried out on 40 to 60 pigs per room for three periods (90, 130 and 162 days of age, respectively, for P1, P2 and P3). Behaviour was assessed through five scans with a two-minute interval between two successive observations. Each behaviour was expressed in relation to the total amount of active behaviours. Injuries were scored on a three-level scale (none, mild, severe). Social behaviour was significantly more important at P1 whereas behaviours related to disturbance were more frequently observed at P3. Bursitis did not differ significantly between periods in S forms but did so in C over time. Small differences were seen between periods for injuries: severe lesions (scratches) and lameness were rare on the different flooring systems and severe wounds and tail lesions were less frequent in S than in C farms. Investigation of the environment was more pronounced on S floors, whereas positive social behaviour was more prevalent in C. All criteria studied were characterised by a noticeable variability in both floor types, showing room for improvement in terms of animal welfare in some forms.