Effects of Different Rooting Materials on Behaviour and Welfare of Finishing Pigs

Abstract

Provision of rooting material is of importance to meet the pig`s need for exploration when housed inside. In this experiment, we aimed to investigate the effects of different types of rooting materials and a weekly rotation in different materials on behaviour and welfare of finishing pigs. We predicted that access to rooting material would lead to more positive and less negative behaviours, and a lower proportion of pigs with bite marks on ears, tail, and body.During two batches with a total of 360 finishing pigs, with 10 pigs per pen, rooting material was provided twice a day (fibrous pellets, peat, straw, hay, a weekly rotation of these materials, or controls with sawdust) over 12 weeks. Behaviour was recorded from video during the first 60 min after material provision, with semi-instantaneous scan sampling (observation for 10 s every 6 min) and 1/0 sampling. In weeks 1,2,3 and 12, bite marks on tail, ears and body were registered, and a human approach test (HAT) was conducted.Provision of rooting material resulted in more exploration, play and tail wagging compared to the control group, except for pellets where exploration level was even lower. Rooting material also led to less tail biting and manipulation of pen fittings compared to the control group. Straw and rotation of materials resulted in less ear biting, and straw in fewer observations with the tail hanging down or tucked between the legs. Aggression was not reduced, and social contact was lower with rooting materials compared to controls. Pigs provided with peat, straw, and hay had a lower proportion of bite marks on the tail, whereas pellets and rotation groups were higher than controls in this respect. All rooting materials except for pellets resulted in a lower proportion of bite marks on the body compared to controls, whereas neither bite marks on ears nor fear of humans were affected by rooting materials. Levels of exploration, play, aggression, ear biting, tail biting, tail curled, wagging, and hanging down, were all higher in the first weeks of the experiment and declined with increasing age. Groups with a weekly rotation in materials showed the highest level of exploration throughout the experimental period.Our results suggest that straw has a very high value as rooting material for finishing pigs, and although material rotation led to most exploration lasting throughout the finishing period, all materials need to be attractive to have a positive effect.

Keywords: Finishing pigs - Rooting material - Environmental enrichment - Behaviour - Welfare