Scientific report on animal health and welfare in fattening pigs in relation to housing and husbandry

Council Directive 91/630/EEC1, as amended, laying down minimum standards for the protection of pigs, requires the Commission to submit to the Council a report, based on a scientific opinion of the European Food Safety Authority (EFSA), concerning the welfare various aspects of housing and husbandry systems for farmed pigs. EFSA has therefore been required to provide a Scientific Opinion on several aspects of this, one concerning fattening pigs. The opinion should include: the effects of stocking density, including group size and grouping methods, space requirements and the impact of stall design and different flooring types taking into account different climatic conditions. The Scientific Opinion was adopted by the Panel on Animal Health and Welfare (AHAW) on 6 September 2007. Based on the scientific data presented in the Scientific Report and risk assessment, conclusions and recommendations were drawn. In relation to disease, respiratory and gastrointestinal infections and production-related diseases can have a major impact on the welfare of fattening pigs. Management, inspection and other disease prevention measures, handling, hygiene, floor type and the manure system have major effects on disease risk and significant importance for ensuring good welfare. At post-mortem slaughter inspection, pigs kept outdoors usually have a lower prevalence of lesions due to respiratory infections than indoor pigs but higher risk of some internal parasites. Leg disorders, which are caused by a complex of factors including genetic selection and high energy and high protein diet, are a major problem. Interactions between many aspects of the biological functioning of pigs and effects of housing and management on welfare are described. Without suitable rooting and manipulation materials, pigs are likely to direct tactile behaviour towards companions using aggression or other causes of poor welfare. Manipulable material makes any floor more attractive for exploration and pigs prefer the presence of straw to an unbedded floor. The provision of appropriate foraging material is difficult in pens with fully slatted floors unless there is automatic shredding in the waste disposal system. If the ambient temperatures are too high, adequate space to separate from other pigs, sufficient contact with a cool floor, access to outdoors, air-flow rates to help evaporation, water on the skin, or more drinking water help to avoid over-heating. In the case of too low a temperature, better insulation of the floor lowers the risk of hypothermia. When there is too little sensory input, because of social isolation, a barren environment or too little light intensity, pigs are likely to show abnormal behavioural and physiological responses. Flashing lights can be disturbing to pigs and poor welfare is also associated with light of a wavelength or intensity that does not allow the pig to discriminate the behaviour of other pigs or materials. The genetic selection for rapid growth and lean meat without enough consideration of other factors has led to some widespread and serious problems. However, selective breeding to eliminate the halothane gene has improved pig welfare. Poor quality pen design can cause poor welfare in pigs because of parts that cause injury, or disturbance and aggression. If pigs do not have sufficient exercise, there can be adverse effects on bone and muscle development. Dunging behaviour (urination and defecation) is facilitated by design of the housing system and good management. Mixing unacquainted pigs leads to a substantial risk of fighting, injury and production loss. Recommendations presented in the Scientific Opinion include the need to provide an environment and management so that the negative consequences of poor welfare such as injurious behaviours, physiological problems and immunosuppression, caused in barren environments, are avoided.