Category Archives: Enrichment

Online Training Improves Understanding of Pig Welfare Legislation

A recent research paper has reported a positive effect of an online training tool on participants’ understanding of taildocking and enrichment legislation, as well as risk factors for tail biting. The training tool was aimed at official inspectors and others involved in enforcement of legislative requirements on pig farms. The research was a collaboration of 15 researchers from 9 EU countries, led by the University of Bristol, UK. The online training tool is free to use and is available in 7 different languages: English, French, German, Polish, Italian, Spanish and Dutch. It can be accessed here:

Click this link to access the EUWelNet Training Tool on pig enrichment and tail docking.

Hothersall, B., Whistance, L., Zedlacher, H., Algers, B., Andersson, E., Bracke, M., Courboulay, V., Ferrari, P., Leeb, C., Mullan, S., Nowicki, J., Meunier-Salaun, M-C., Schwarz, T., Stadig, L. & Main, D. 2016 Standardising the assessment of environmental enrichment and tail-docking legal requirements for finishing pigs in Europe. Animal Welfare 25:499-509.


An online training package providing a concise synthesis of the scientific data underpinning EU legislation on enrichment and taildocking of pigs was produced in seven languages, with the aim of improving consistency of professional judgements regarding legislation compliance on farms. In total, 158 participants who were official inspectors, certification scheme assessors and advisors from 16 EU countries completed an initial test and an online training package. Control group participants completed a second identical test before, and Training group participants after, viewing the training. In Section 1 of the test participants rated the importance of modifying environmental enrichment defined in nine scenarios from 1 (not important) to 10 (very important). Training significantly increased participants’ overall perception of the need for change. Participants then rated nine risk factors for tail-biting from 1 (no risk) to 10 (high risk). After training scores were better correlated with risk rankings already described by scientists. Scenarios relating to tail-docking and management were then described. Training significantly increased the proportion of respondents correctly identifying that a farm without tail lesions should stop tail-docking. Finally, participants rated the  importance of modifying enrichment in three further scenarios. Training increased ratings in all three. The pattern of results indicated that participants’ roles influenced scores but overall the training improved: i) recognition of enrichments that, by virtue of their type or use by pigs, may be insufficient to achieve legislation compliance; ii) knowledge on risk factors for tail-biting; and iii) recognition of when routine tail-docking was occurring.

EUWelNet Training Tool enrichment and tail docking

Note that the training tool is being used in Poland to train animal science students, farm assurance in the UK has shown recent interest in using the tool, and the Austrian pig health service is compiling a brochure based on EUWelNet on tail biting/enrichment material.

Enrichment devices for weaned pigs

Effects of different enrichment devices on some welfare indicators of post-weaned undocked piglets. By E. Nannoni, , , L. Sardi, M. Vitali, E. Trevisi, A. Ferrari, F. Barone, M.L. Bacci, S. Barbieri, G. Martelli. Appl. Anim. Behav. Sci.


Two experimental trials were carried out in order to test the effectiveness of different environmental enrichments in improving the welfare of weaned pigs. A total of 120 undocked piglets was used. In trial one, group C1 received a metal chain and group WL a wooden log mounted on a frame. In trial two, the enrichments proposed were a hanging chain (group C2), an edible block (group ED) and a wooden briquette (group WB) mounted on a frame. The effectiveness of the enrichments was assessed in terms of animal behaviour, cortisol from bristles, hematologic and hematic profiles, cutaneous (skin and tail) lesions. Growth parameters were also recorded. Although some differences were detected in growth parameters in trial 1 (with C1 group having better productive outcomes than WL group) and some minor differences were observed in animal behaviour in both trials, the overall welfare status did not differ among the experimental groups. On the other hand, no welfare issues emerged in groups C1 and C2, receiving the enrichment device which is generally believed to be scarcely attractive, i.e. the hanging chain. We can therefore conclude that, if no managerial errors are made (floor space availability, feed inadequacy, group stability, microclimate, illumination), under the tested experimental conditions, hanging chains can provide a sufficient environmental enrichment for undocked piglets, even when compared to more attractive enrichments (e.g. an edible block).


• The effectiveness of different enrichments was tested on undocked weaners.
• Minor differences were observed in animal behaviour in both trials.
• Overall welfare status did not differ between the experimental groups.
• In controlled conditions none of the proposed enrichments improved piglets’ welfare.
• Under controlled conditions, all devices provided a similar enrichment level.

Investigating the effect of rooting substrate provision on the group lying behaviour of pigs using machine vision

Investigating the effect of rooting substrate provision on the group lying behaviour of pigs using machine vision. By: Abozar Nasirahmadi, Sandra A Edwards, Barbara Sturm,
Conference Paper · June 2016. Conference: CIGR-AgEng Conference, Aarhus, Denmark


To deliver good animal welfare, pigs should have a hygienic and undisturbed lying area within the pen. However, the provision of a rooting material is desirable to meet behavioural needs and this can only be given onto solid floor away from the dunging area, which might disrupt the group lying pattern. To determine whether daily provision of a rooting material (maize silage) onto a solid plate in the lying area of a fully slatted pen resulted in changed lying location, the lying patterns of pigs in 6 enriched pens were compared with those of 6 control pens which had only a suspended enrichment toy. Since visual monitoring of pig behaviours over long periods is very time consuming, an image
processing technique was applied to identify any changes pig lying positions and behaviour. Pigs were monitored by top view CCTV cameras and animals were extracted from their background using image processing algorithms. The x–y coordinates of each binary image were used for ellipse fitting algorithms to localize each pig. In order to find the lying positions, ellipse parameters were calculated for all fitted ellipses. Each pen was virtually subdivided into four zones in images and the centroid of each fitted ellipse was used for finding the position of each lying pig at 10 minute intervals during their lying period, after use of an algorithm to remove images in motion preceding the scan. By means of the ellipse properties it was possible to automatically find and compare the
changes in lying position of pigs in the pens. Results showed that once daily provision of rooting material did significantly change lying behaviour.

Proper enrichment for intensively-farmed pigs – From review to preview

Bracke, M.B.M. 2016. Enrichment materials for intensively-farmed pigs – From review to preview (Conference abstract & presentation, ICPD 2016). In: Kemp, B. et al., 2016. 16th International Conference on Production Diseases in Farm Animals. June 20-23, 2016. Wageningen, NL. p. 179.


Tail biting is a well-known production disease in intensively-farmed pigs raising concern for animal welfare, e.g. related to the practice of routine tail docking. To reduce tail biting pigs are provided with enrichment materials. EU legislation requires that pigs have permanent access to a sufficient quantity of material to enable proper investigation and manipulation activities. In order to meet this directive many pigs are provided with a metal chain with or without a rather indestructible object attached to the chain. The European commission recently revised current guidelines as to what constitutes adequate enrichment, apparently moving into the direction of the status-quo in welfare schemes. Building on extensive previous work at Wageningen UR Livestock Research, especially on the modelling of pig enrichment (the so-called RICHPIG model) a review is presented of our current state of knowledge. In addition, an outline is given as to how so-called AMI-sensors, measuring Animal-Material Interactions (AMI) (semi-)automatically, can be used to assess the pig’s need for enrichment, also in relation to aspects associated with health status, such as feed restriction, biting wounds and streptococcus infection. It is suggested that the use of chains with or without rather indestructible materials such as pipes, balls or (hard)wood is generally inadequate to enrich the pens of intensively-farmed pigs. An evolutionary mechanism appears to be underlying the causation of multifactorial welfare problems in general, the issues of enrichment, tail biting and tail docking in pigs in particular. In this respect ongoing selection for increased resource efficiency has been exerting a profound impact on livestock production. Various routes are explored as to how persistent welfare problems may be resolved, including a method that has been called Intelligent Natural Design (IND).

Branched chain
Two organic pigs interacting simultaneously with a branched chain in the snow. Despite access to a straw bed for rooting, even organic pigs may interact with such chains for long periods of time, esp. directed towards the floor. In fact they will root the chain on the floor more than twice as much as playing with it in a horizontal position. In intensive pig production chains are often (too) short, and when a hockey-type ball or ‘sustainable’ plastic pipe is attached to the end of such a chain the pigs’ interest, and their welfare, is often even reduced further. By contrast, to improve the chain further 7mm stainless-steel anchor chains may be recommended for growing pigs over the cheaper c-chain shown here, as anchor chains have heavier and more rounded shackles.

See also an older previous presentation on tail biting.

Bracke, M.B.M, Wolthuis, M., Zonderland, J. J., Kluivers, M., 2011. TAILS TO TELL – Tail docking, tail biting and enrichment for pigs – Experiences from the Netherlands. Herning, DK, May 25-26, 2011.

Improving Welfare, Health and Productivity in Pigs by Optimizing Adaptation

Improving Welfare, Health and Productivity in Pigs by Optimizing Adaptation
By J.E. Bolhuis and B. Kemp, 2016. Journal of Animal Science (conference paper, March 14-16, 2016, Des Moines, USA).


Welfare problems in pigs often arise from an imbalance between the challenges they are exposed to and their adaptive capacity. A major challenge for pigs is the weaning transition. Weaning often results in reduced growth, intestinal problems and damaging behaviors. The natural behavior of pigs and their adaptive strategies can inspire us to reduce weaning-related problems. We found that early ingestion of feed can be stimulated by facilitating information transfer from sow to piglet, both through flavor learning in utero and social learning. This early feeding, in turn, seems vital for a good post-weaning performance. Also enrichment substrates that stimulate early sampling of feed positively affect piglet performance around weaning. We are developing a multi-litter group housing system for lactating sows and their piglets in which both opportunities for sow-piglet information transfer and enrichment substrates are provided. Piglets raised in this system and kept in large groups post-weaning show improved performance until at least 9 weeks of age. Measures that facilitate the weaning transition in pigs typically also reduce the occurrence of damaging behaviors directed at pen mates, such as tail biting and ear biting. These behaviors both reflect and generate welfare problems, and are influenced by multiple factors. Apart from the impact of early life conditions, we studied the contribution of (genetic) characteristics of pigs and of their environment to the tendency of displaying damaging behaviors. Tail biting seems associated with fearfulness, serotonin metabolism and with (genetic and phenotypic) production characteristics. Excessive levels of damaging behaviors lead to reduced growth in the victims, and we therefore investigated the impact of a novel breeding strategy, targeting indirect genetic effects on growth. Pigs with high indirect genetic effects on growth inflicted less tail damage and showed less ear biting. They also seemed less fearful and showed lower leukocyte, lymphocyte and haptoglobin levels. Enrichment with straw bedding had similar beneficial effects additive to those of the new genetic strategy. On most farms it is, however, not feasible to provide pigs with straw, and we therefore studied the effectiveness of a simple enrichment material – a burlap sack – and found a twofold reduction in damaging behaviours and a five-fold reduction in the proportion of animals with a tail wound. In conclusion, – small and large – changes in genetic background, early life conditions and quality of the environment that contribute to the adaptive capacity of pigs, and reduce their stress load, can be used to improve pig welfare and performance in concert.

Impact of straw on gastric ulceration in pigs

Impact of the amount of straw provided to pigs kept in intensive production conditions on the occurrence and severity of gastric ulceration at slaughter.
Herskin MS, Jensen HE, Jespersen A, Forkman B, Jensen MB, Canibe N, Pedersen LJ. 2016. Res Vet Sci. 104: 200-6.


This study examined effects of the amount of straw offered on occurrence and severity of gastric lesions in pigs kept in pens (18 pigs, 0.7m(2)/pig) with partly slatted flooring and 10, 500 or 1000g straw/pig/day from 30kg live weight. The pigs had ad libitum access to dry feed. Forty-five pigs were used, three from each of 15 pens. After euthanisia, the dimension of the non-glandular region of the stomach was measured. Lesions were characterized and scored. Irrespective of straw provided, 67% of the pigs showed signs of gastric pathology. Pigs provided with 500 or 1000g straw were pooled as ‘permanent access’. The proportion of pigs with ulcerations was reduced by permanent access to straw (7 vs. 33%; P<0.05), suggesting that permanent access to straw may improve animal health, and be considered as one possible strategy to limit gastric ulceration in pigs.

500gr straw/pig/day
500gr straw/pig/day
10gr straw/pig/day
10gr straw/pig/day

European commission initiative to reduce tail docking and improve enrichment

March 2016 the European Commission takes another step to reduce tail docking and improve enrichment for pigs as part of its animal welfare strategy.

Here are some relevant phrases from the announcement made on the Commission’s website:

The welfare of pigs is assured by Council Directive 2008/120/EC.

It applies to all categories of pig and lays down minimum standards for their protection:

  • Providing permanent access to …. materials for rooting and playing

COMMISSION RECOMMENDATION (EU) 2016/336 of 8 March 2016 on the application of Council Directive 2008/120/EC laying down minimum standards for the protection of pigs as regards measures to reduce the need for tail-docking.

STAFF WORKING DOCUMENTpdf(706 kB) on best practices with a view to the prevention of routine tail-docking and the provision of enrichment materials to pigs [SWD(2016)49 final] Following the adoption of the Commission Recommendation (EU) 2016/336 as regards measures to reduce the need for tail-docking, the staff working document provides useful tools to a harmonised understanding on how the provision of manipulable material and avoidance of tail-docking can be practically achieved.

The working document recognises that proper enrichment is important to help prevent tail biting, and hence the need for tail docking.

Specified as unsafe are synthetic ropes, tyres, dry wood, dry sawdust, poorly stored straw, untreated peat/mushroom compost and dirty objects.

Furthermore proper enrichment should have one or more of the following qualities:

  • Edible or feed-like (to eat or smell)
  • Chewable (to bite)
  • Investigable (to root)
  • Manipulable (to change its location, appearance or

Provision should be

  • of sustainable interest
  • accessible
  • of sufficient quantity
  • clean
Materials of marginal interest should not be used as essential or single component of pig
enrichment materials. They can provide distraction but should not be considered as
fulfiling the essential needs of the pigs. Other materials should also be provided.
Materials of marginal interest include objects, such as hard plastic piping or chains.
Marginal materials may supplement suboptimal materials like stones or strawdust briquette.

Can tail damage outbreaks in the pig be predicted by behavioural change?

Vestbjerg Larsen, M.L., Andersen, H.M-L, Pedersen, L.J. 2016. Can tail damage outbreaks in the pig be predicted by behavioural change? The Veterinary Journal 209: 50-56.


Tail biting, resulting in outbreaks of tail damage in pigs, is a multifactorial welfare and economic problem which is usually partly prevented through tail docking. According to European Union legislation, tail docking is not allowed on a routine basis; thus there is a need for alternative preventive methods. One strategy is the surveillance of the pigs’ behaviour for known preceding indicators of tail damage, which makes it possible to predict a tail damage outbreak and prevent it in proper time. This review discusses the existing literature on behavioural changes observed prior to a tail damage outbreak. Behaviours found to change prior to an outbreak include increased activity level, increased performance of enrichment object manipulation, and a changed proportion of tail posture with more tails between the legs. Monitoring these types of behaviours is also discussed for the purpose of developing an automatic warning system for tail damage outbreaks, with activity level showing promising results for being monitored automatically. Encouraging results have been found so far for the development of an automatic warning system; however, there is a need for further investigation and development, starting with the description of the temporal development of the predictive behaviour in relation to tail damage outbreaks.

Tail postures
Tail postures
Pigs resting on straw
Pigs resting on straw

See also the related editorial:

Zonderland, J.J. and Zonderland, M.A., 2016. Behavioural change by pig producers is the key factor in raising pigs with intact tails (Editorial). The Veterinary Journal.

News from The Netherlands (and Germany)

This first week of February 2016 two items related to tail biting appeared in farmers’ press in The Netherlands. In addition, we recently provided input into a European project on the welfare of poultry, which will be reported on briefly below.

One news item announced that farmers are invited at the Intensive Farming Fair in Venray (LIV Venray), March 1-3 2016. At the fair two finished tail-biting projects will be presented and discussed with entrepreneurs who are active in intensive farming. One of the projects is ‘Keeping pigs with intact tails’.

The other item was a report on the German tail biting (Ringelschwanz-)project. First results of the curly-tail project in North-Rhine Westphalia showed that more than one quarter of piglets at 15 participating research farms had damaged tails before the end of the rearing period. At some farms half of the tails had been bitten. At the 15 farms participating in the study 30-94 piglets had been reared on each farm without tail docking. Outbreaks of tail biting appeared to be associated with streptococcus infections. Prevention and intervention strategies included providing dried maize silage or alfalfa hay twice daily and the isolation of biters respectively. Most tail biting occurred between week 2 and 4 after weaning. This level of tail biting is not so good news. If these levels of tail biting would persist, it may indicate that intensive systems cannot be made compatible with acceptable levels of animal welfare. Fortunately, however, experiences in Finland indicate that it should be possible to keep undocked pigs in conventional systems at much lower levels of tail biting (around 2% based on slaughter house data).

The German farmers union and North-Rhine Westphalia have agreed 1.5 years ago that they intend to stop tail docking by 2017. This will be done provided on-farm research shows that tail biting among pigs with intact tails does not reduce animal welfare. The general expectation is that the objective of safely quitting tail docking cannot be met.

From a Dutch research perspective two notes appear to be relevant:

The first is that our semantic-modelling approach provides a unique methodology to determine/assess  the cut-off point between the welfare impacts of tail biting and tail docking using formalised biological reasoning and scientific evidence. In this computation one must take into account all relevant aspects: So, not only the point that the welfare of tail bitten pigs is reduced due to blunt trauma (biting) compared to the sharp trauma of tail docking at an earlier age. But also the point must be recognised that the welfare of tail biting pigs may relatively be improved when they can bite their penmates’ tails, compared to when they cannot (other things being equal, i.e. lack of suitable enrichment). What matters for welfare as considered from the animals’ point of view is the extent to which they can satisfy their needs, e.g. for biting and the expression of species-specific foraging behaviour, taking into account also the activation of coping mechanisms such as redirected and harmful-social behaviours.

The second thing to note about the results of the German research project is the following. In addition to taking note of the bad news (many bitten tails, which has to be taken seriously, perhaps even to the point that the conclusion must be drawn that intensive systems are not compatible with acceptable animal welfare), one may also try to move forwards for the time being by focussing on the good news: Two out of the 15 pilot farms in Germany managed to keep all piglets’ tails intact. Other farms may learn from what was done on these farms to keep tails intact. Furthermore, since the EC Directive requires that all farms try to periodically keep at least some intact pigs, a 10% success rate could provide sufficient scope for progress at the population level, even when the causes of the success are poorly understood. This can be concluded from a methodology we designed previously to solve complex welfare problems like feather pecking in poultry and tail biting in pigs. This methodology has been called ‘Intelligent Natural Design’ (INO in Dutch; see also Bracke, 2010). It basically uses evolution to select the best farms to make increasing progress towards the objective of completely stopping the practice of routine tail docking in pig farming.

Countering the routine practices of tail docking and beak trimming, as well as preventing and treating outbreaks of tail biting and feather pecking requires an understanding of tipping points. Recently, we modified our tipping-bucket model for tail biting for inclusion on the Henhub website. This website, which is part of the Hennovation project, gives information about welfare issues in poultry, esp. (at present) feather pecking. On that site the modified tipping-bucket model can be found under the post describing the mechanism of feather pecking.

Tipping-bucket model of tail biting in pigs
Tipping-bucket model of tail biting in pigs

Bracke, M.B.M. 2010. Towards long(er) pig tails: New strategy to solve animal welfare problems. In: Lidfors, L., Blokhuis, H., Keeling, L., Proceedings of the 44th Congress of the ISAE, August 4-7 2010, Wageningen Academic Publishers, Wageningen, p. 135. (Poster, ISAE 2010, Uppsala, Sweden, Aug 4-7.

Strategies to reduce the risk of tail biting in pigs managed on slatted floors

By Jen-Yun (author)

A 4-year project of “Strategies to reduce the risk of tail biting in pigs managed on slatted floors” has started. It is a collaboration between Teagasc, SRUC and the University of Edinburgh.
Below is a poster on the project presented in the Teagasc Pig Farmers’ Conference 2015.
The project will aim to explore ways to reduce tail-biting on slatted floor systems where straw is not available by environmental enrichment and nutritional strategies.
The enrichments used at the moment are compressed straw and different wood types.
Later the project will also investigate the effects of various lengths of tails, measures to predict tail-biting outbreaks and methods to interfere effectively.
The project will be supervised by Dr Keelin O’Driscoll (Teagasc), Dr Rick D’Eath (SRUC), Dr Dale Sandercock (SRUC), and Prof Natalie Waran (University of Edinburgh).
Dr Amy Haigh is the postdoctoral researcher working together on this project in Teagasc, and Dr Laura Boyle and Dr Edgar Garcia Manzanilla are also the collaborating researchers in Teagasc. I (Jen-Yun) am the PhD student on this project.
fwd uk jy291015 entail poster - JC 28102015c