The risks associated with tail biting in pigs and possible means to reduce the need for tail docking considering the different housing and husbandry systems Scientific Opinion of the Panel on Animal Health and Welfare (Question No EFSA-Q-2006-013) Adopted on 06 December 2007

Council Directive 91/630/EEC2, 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. Following a request from the European Commission, the Panel on Animal Health and Welfare was asked to deliver a Scientific Opinion on the risks associated with tail biting in pigs and possible means to reduce the need for tail docking considering the different housing and husbandry systems. The Scientific Opinion was adopted by the Panel on Animal Health and Welfare (AHAW) on 6 December 2007. Based on the scientific data presented in the Scientific Report conclusions and recommendations were drawn, as well as some recommendations for future research. Evidence indicates that tail-biting pigs are likely to be frustrated and hence experiencing reduced welfare. Tail-biting can cause very poor welfare and tail-docking is likely to be painful, both in the short term and as a result of possible long-term pain from neuroma formation. Tail biting is associated with a variety of pathological changes ranging from spinal abscesses to pyaemia in different parts of the body. Such changes may be associated with reduced growth rate or in more severe cases, total carcass condemnation. Tail biting is considered as an abnormal behaviour. The need to perform exploration and foraging behaviour is considered to be a major underlying motivation. The occurrence of tail biting has a multi-factorial origin and there is evidence in the report that some causal factors have more weight, such as the absence of straw, the presence of slatted floors and a barren environment. Absence of straw or a particulate, rootable substrate is an important hazard for tail biting. However, both the amount of straw (full bedding better than limited provision from a rack) and its form (long straw better than chopped) are also of importance. It was concluded that there is little evidence that provision of toys such as chains, chewing sticks and balls can reduce the risk of tail biting. Heritability of tail-biting has been evaluated and its value found to be high enough for selection. Moreover, a phenotypic correlation between tail-biting behaviour and higher lean tissue growth rate has been reported. A hazard for tail biting is competition for feed and/or inadequate feed intake, inadequate dietary sodium, deficiency of dietary essential amino acids, and a sudden change in diet composition, especially to a lower nutrient density. In relation to climate condition, tail biting risk seems to be increased in autumn season, and hazards for tail biting are heat stress as well as cold stress and high airspeed. Circumstantial data, anecdotal reports and practical experience strongly suggest poor health status to be a hazard for tail biting. The efficacy of tail docking to reduce the frequency of tail biting is very difficult to estimate since it depends on the level of tail biting in control undocked pigs. Indeed, tail docking is all the more efficient in current intensive housing systems for pigs since environmental and possibly also genetic hazards for tail biting are prevalent. Under common intensive farming conditions, tail docking reduces the frequency of tail biting, but does not completely eliminate the problem when unfavourable conditions persist. In relation to the results obtained in the Risk Assessment process, some of the above mentioned hazards that have a high prevalence in the EU population came out as major risk factors for tail biting. In order to further assess risks associated with tail biting and the severity of docking tails in pigs, research is needed that addresses, among others, the difference in prevalence of tail biting between docked and undocked pig populations in different housing systems, the severity and the duration of chronic pain, and the genetic, environmental, age and sex differences of tail-biting behaviour performance. Research is also needed to better understand the fundamental causal factors leading to tail biting and to define tools for early detection of tail biting in farms. The methodology and the results (Conclusions and Recommendations) of this opinion as well as the previous opinions on Pig Welfare, should be further analysed identifying welfare indicators (in particular animal-based) suitable for the development of an animal welfare monitoring system.