EN-181 
                                                                                                          
                                                                                                                           
                                             TECHNICAL REPORT submitted to EFSA 
                           Preparatory work for the future development of animal based measures 
                                                                                              1
                                                     for assessing the welfare of pigs  
                           Report 2: Preparatory work for the future development of animal based 
                           measures for assessing the welfare of weaned, growing and fattening pigs 
                            including aspects related to space allowance, floor types, tail biting and 
                                                             need for tail docking 
                                                                 2                   2                                3
                             Prepared by Hans Spoolder , Marc Bracke , Christine Mueller-Graf , 
                                                                                     4
                                                               Sandra Edwards  
                  
                 2 
                  Wageningen UR Livestock Research, PO box 65, 8200 AB, Lelystad, The Netherlands  
                 3  Federal  Institute  for  Risk  Assessment  (BfR)  Head  of  Unit  Epidemiology,  Biometry  and 
                 Mathematical Modelling Department Scientific Services, Alt-Marienfelde 17-21, D-12277 Berlin, 
                 Germany 
                 4 Newcastle University, School of Agriculture, Food and Rural Development Agriculture Building 
                 Newcastle upon Tyne, NE1 7RU, UK 
                     
                            
                           Abstract 
                  
                 The EFSA Animal Health and Welfare panel is requested to develop several scientific opinions 
                 concerning animal based measures to assess the welfare of livestock animals. Before this work can 
                 start, it is important that conclusions and recommendations of the EFSA scientific opinions are up 
                                                                    
                    1 (Question No EFSA-Q-2011-00879)  
                    Accepted for Publication on 05 July 2011 
                     
                 The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out 
                 exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a 
                 tender  procedure.  The  present  document  is published complying with the transparency principle to which the European Food Safety 
                 Authority is subject. It may not be considered as an output adopted by EFSA. EFSA reserves its rights, view and position as regards the 
                 issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. 
                                       European Food Safety Authority - Largo N. Palli 5/a, I - 43121 Parma 
                                      Tel: (+39) 0521 036 200 • Fax: (+39) 0521 036 0200 • www.efsa.europa.eu 
                     
                                                           Preparatory work for pig welfare indicators – Report 2 
                                                                                                    
              to date. The main objective of this report is to review the pig welfare literature to identify gaps and 
              potential areas to strengthen or amend three recent pig welfare opinions: one on the welfare of 
              Fattening pigs (2007), another on Space allowances and floor design (2005) and a final one on Tail 
              biting  (2007).  The  literature  review  was  done  by  a  group  of  authors  and  reviewers,  under  the 
              supervision of an editorial team. Over 200 new scientific literature references are quoted. Regarding 
              the first opinion, this review presents 11 new or revised conclusions. In addition it suggests several 
              new recommendations. These include suggestions for maximum noise levels and ammonia levels, 
              and minimum light duration. Furthermore, attention is drawn to the need of pigs to cool themselves 
              when ambient temperature is high. Finally, the recommendations also emphasise the need to further 
              study  the  relationship  between  space  allowance  and  negative  social  behaviours.  Regarding  the 
              second opinion, it draws 5 conclusions. The recommendations predominantly confirm those in the 
              original opinion, but also emphasise the need for a well maintained substrate to reduce leg problems 
              and gastric ulcers. For the third opinion, 10 new conclusions are added.  The recommendations 
              include the monitoring of tail length at the slaughter line, and the use of new management and 
              housing information to avoid the need for tail docking. It also suggests that an intact curly tail can 
              be regarded as the single most important welfare indicator in finishing pigs.      
                      Summary 
              The EFSA Animal Health and Welfare panel is requested to develop several scientific opinions 
              concerning  animal  based  measures  to  assess  the  welfare  of  livestock.  The  main  background 
              documents for these mandates are the EFSA Scientific Opinions on the welfare of livestock and the 
                            ®
              Welfare Quality  assessment protocols. EFSA has issued in the past the 5 scientific opinions on 
              different aspects related to the welfare of pig. Three of these are: i) Animal health and welfare in 
              fattening pigs in relation to housing and husbandry (2007); ii) The welfare of weaners and rearing 
              pigs: effects of different space allowances and floor (2005) and iii) 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 (2007). The terms of reference (ToRs) of the Commission mandates 
              on animal based measures to assess the welfare of livestock animals suggest that such measures 
              could be used to check whether the recommendations listed in the EFSA scientific opinions are 
              fulfilled  or  not.  It  is  therefore  important  that  conclusions  and  recommendations  of  the  EFSA 
              scientific opinions are up to date.  
              The 5 scientific opinions are evaluated in two reports. The main objective of both reports is to 
              present  preparatory  work  for  the  future  mandate  on  animal  based  measures  for  assessing  pig 
              welfare.  It  is  a  review  of  the  literature  provided  in  the  opinions  in  order  to  identify  gaps  and 
              potential areas to strengthen or amend the conclusions and recommendations of such opinions. It 
              also aims to identify hazards that may be revised by the AHAW Panel in light of the newly available 
              scientific evidence. The present report addresses the three opinions referred to above, presented 
              here as sub-reports C, D and E, respectively. 
              The editors of the two reports used a step wise iterative approach in which they involved experts 
              from different research institutes. An initial literature search resulted in a large number of abstracts, 
              of which more than 800 were read by the editorial team and analysed for statements relevant to the 
              two reports. Authors were recruited and were sent one or more paragraphs with statements derived 
              from the abstracts. They were asked to add their expertise, any missing references and statements, 
              and to develop the statements into texts for each paragraph. The draft paragraph texts were then 
              The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out 
              exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a 
              tender  procedure.  The  present  document  is  published complying with the transparency principle to which the European Food Safety 
              Authority is subject. It may not be considered as an output adopted by EFSA. EFSA reserves its rights, view and position as regards the 
              issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. 
                 
                                          Preparatory work for pig welfare indicators – Report 2 
                                                                        
          sent to „first reviewers‟. These reviewers received large chunks of each report (several paragraphs 
          from  several  authors)  and  developed  the  texts  further.  They  provided  additional  expertise  or 
          references. Subsequently, five „second reviewers‟ were asked to do the same as the first reviewers. 
          In a final step the editorial team over-viewed the text and put together the list of recommendations 
          and associated hazards, based on the original recommendations list of the original EFSA reports.  
          The  literature  searches  conducted  at  the  beginning  of  this  project  (for  both  Reports  1  and  2) 
          resulted in 6435 unique references (for both reports). Databases searched included CAB Abstracts, 
          Agricola and ISI Web of Knowledge (which included both the Science Citation Index Expanded 
          (SCI-EXPANDED) and the Conference Proceedings Citation Index- Science (CPCI-S) databases). 
          General searches were conducted on pig welfare as of (and including) 2007 using the key words 
          pig*, sow*, boar*, welfare, well-being, behav* and stress. Specific searches were conducted on 
          space and floors (as of 2005) using the key words floor*, space and castr*. 
          For the present report a total of over 200 scientific publications were used to formulate additional 
          conclusions and recommendations to the original opinions.  
          Conclusions for sub-report C on “Animal health and welfare in fattening pigs in relation to housing 
          and  husbandry”  include:  i)  genetic  traits  of  fearfulness  and  aggression  have  been  identified  and 
          could  be  incorporated  in  practical  breeding  programmes  to  improve  welfare,  ii)  all  new  data 
          reinforce the importance of providing suitable enrichment materials to allow expression of species 
          relevant behaviours and reduce risk of injurious biting, iii)  destructibility, hygiene and novelty are 
          key elements of suitable enrichment, iv) provision of cooling facilities for pigs are important in any 
          situation of increased ambient temperature or endogenous heat production, v) Ammonia levels of 
          >20ppm have adverse effects on pig physiology and behaviour, vi) There is a high prevalence of 
          locomotory disorders on many farms which should be addressed through genetic and environmental 
          improvement. 
          Recommendations for sub-report C include: i) since pigs have limited abilities to loose heat (they 
          cannot sweat), pigs should be allowed to seek cooling when overheated, not only in case of elevated 
          ambient temperatures, but also in cases of elevated activity, fever and high metabolism, ii) ammonia 
          levels in pig housing should not exceed 20ppm, iii) noise levels in pig housing should be <80dB, iv) 
          although the ability of pigs to discriminate between small visual cues at light intensities from 12 to 
          80 lux does not appear to change, a light intensity of  >80 lux during activity periods reduces 
          aggression  compared to 40 lux. A minimum light period of 14h/day should be provided where 
          artificial light is used, v) further research is needed to specify in more detail the effects of reduced 
          space allowances on negative social behaviours, as well as the interaction between space allowance 
          and enrichment, so as to identify the extent to which these factors can act as substitutes for each 
          other. 
          Conclusions for sub-report D on “The welfare of weaners and rearing pigs: effects of different space 
          allowances and floor” include: i) the allometric approach appears valid for pigs over a wide weight 
          range, ii) behavioural measures suggest a higher optimum k value (0.037-0.039) than production 
          measures (0.032-0.035), iii) the amount of space needed by an individual appears independent of 
          group size, iv) walking safety and comfort is impaired by soiled floors, v) the effects of floor type 
          on health are equivocal, with further evidence that solid floors are better for respiratory disease but 
          detrimental to enteric and endoparasitic infections. The original recommendations of sub-report C 
          The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out 
          exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a 
          tender  procedure.  The  present  document  is  published complying with the transparency principle to which the European Food Safety 
          Authority is subject. It may not be considered as an output adopted by EFSA. EFSA reserves its rights, view and position as regards the 
          issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors. 
             
                                                             Preparatory work for pig welfare indicators – Report 2 
                                                                                                        
              are  supported by the new data, but also include that a well maintained substrate such as straw 
              should be used to reduce leg problems and gastric lesions. 
              Conclusions for sub-report D 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” include: 
              i)  tail  and  ear  lesions  are  indicative  of  reduced  welfare  (now  and/or  in  the  past).  They  can  be 
              detected  fairly  easily,  even  at  the  slaughterhouse.  Healed  lesions  should  be  included  in  the 
              observations, ii) while lack of enrichment is a main reason for such lesions, also a range of other 
              factors may be involved e.g. reduced health, thermal inadequacies, problems with feed and water, 
              etc.).  All  of  these  are  associated with reduced welfare, iii) use of group selection as a breeding 
              strategy has the potential to reduce genetic predisposition to tail bite, iv) reliable behavioural signs 
              of an impending tail biting outbreak have been identified and can be used to take precautionary 
              measures, v) tail and ear biting behaviour may be treated with enhanced enrichment (e.g. ample long 
              straw provided fresh twice daily) throughout the pig‟s life. However, other risk factors (stocking 
              density, ventilation, feed, ...) should be investigated or audited too, vi) research to date indicates 
              that  while  toys  may  show  some  reduction  in  tail  biting,  especially  when  they  have  destructible 
              components, natural substrates such as straw or compost seem to be necessary to reduce biting 
              problems to acceptable levels in problem pens. Recommendations for sub-report D include: i) the 
              wealth  of  information  on  how  to  reduce  the  risk  of  tail  biting  (such  as  providing  suitable 
              enrichment, ensuring a good thermal environment and appropriate feeding) without docking pig 
              tails,  should  be  used  to  underpin  the  importance  of  preventative  measures,  ii)  monitoring  at 
              slaughter should include also tail length (in addition to tail lesions) as well as ear shape (missing 
              parts of the ears) and biting wounds on flanks and legs, iii) an intact curly tail may well be the single 
              most important animal-based welfare indicator for weaned, growing and finishing pigs (at herd 
              level). In addition, it stands for high-quality management and respect for the integrity of the pig. 
              The hazards associated with the recommendations were presented for each sub-report. Overall, no 
              new hazards were identified, although the evidence for many existing hazards was strengthened. 
               
              Key words:        
              Pig welfare, fattening pig, tail biting, swine housing 
              The present document has been produced and adopted by the bodies identified above as author(s). This task has been carried out 
              exclusively by the author(s) in the context of a contract between the European Food Safety Authority and the author(s), awarded following a 
              tender  procedure.  The  present  document  is  published complying with the transparency principle to which the European Food Safety 
              Authority is subject. It may not be considered as an output adopted by EFSA. EFSA reserves its rights, view and position as regards the 
              issues addressed and the conclusions reached in the present document, without prejudice to the rights of the authors.