Tag Archives: Enrichment

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.

On-farm tail biting prevention in long-tailed pigs – results from a producer questionnaire in Finland

On-farm tail biting prevention in long-tailed pigs – results from a producer questionnaire in Finland. By Valros, A., C. Munsterhjelm, L. Hänninen, T. Kauppinen, M. Heinonen, 2016. Royal Dublin Society: Abstracts book of the 24th International Pig Veterinary Society (IPVS) Congress, Dublin, Republic of Ireland 7-10th June 2016. p. 144.


Introduction: Tail biting is a serious welfare problem in pigs, causing substantial economic losses. In the majority of the EU countries, tail docking is used to reduce the incidence of tail biting. However, many of the risk factors for tail biting are related to suboptimal management, and tail biting can be reduced by corrective management decisions. There are few studies on which preventive measures producers themselves value as most important.

Materials and Methods: A questionnaire was distributed via slaughterhouse webpages in 2015. Producers were asked to score the importance of handling different tail-biting risk factors on their own farms, as well as about which manipulable materials they use, and find efficient. In addition, we asked about their opinions on tail biting and tail docking. A total of 70 producers replied, 54 of these replies were regarding fattening pigs, and 16 regarding weaned pigs. The size of the pig units varied between 100 and 6400 pigs, with an average of 1307 pigs. Finland banned tail docking in 2003, so all farms raised long-tailed pigs only.

Results: On average, the producers reported a prevalence of tail biting of 2,3% on their farms, which corresponds well with values reported at Finnish abattoirs. Most producers found tail biting not to be a big problem on their farms and 62% of the farmers found it very unlikely that they would raise tail docked pigs even if it was legal in Finland. The more tail biting reported on the farm, the more problematic the farmers found tail biting, and the more prone they were to say they would probably tail dock if they were allowed to. According to the Finnish producers, the most important factor to prevent tail biting is that there is enough feeding space for the pigs. Altogether, four feeding-related risk factors were included in the top-10 measures to prevent tail biting. Also pig health was considered very important, as well as a good quality of piglets, and controlling air movements in the pen. Straw, newspaper, hay and cardboard were considered the most efficient manipulable materials to prevent tail biting. If tail biting has already started in the pen, the producers ranked identifying and removing the tail biter from the pen as most important, followed by adding bedding-type manipulable materials.

Conclusion: The results are partly in accordance with experimental and epidemiological studies on risk factors for tail biting, but the high focus on feeding-related and health factors is interesting. Finnish farmers appear to handle the tail docking ban well, and do not, on average, find tail biting a very serious problem.

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.

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.

Re­search: How do Finnish pro­du­cers deal with long-tailed pigs?

Tail biting is a common and serious welfare problem in pig production, causing large economical losses. Tail docking is performed routinely in most EU countries to reduce the tail biting risk. However, tail docking is painful, and does not prevent tail biting totally. In Finland, tail docking is forbidden. New research shows that most Finnish producers would not raise tail docked pigs if it were possible.

Professor Anna Valros led a project asking with a web-survey from the Finnish farmers how they manage to raise pigs without tail docking. Respondents scored feeding-related issues to be most important for prevention of tail biting, identifying and removing the biting pig as most important intervention measures, and straw as the most important manipulable material when preventing tail biting. Tail biting was not perceived as a serious problem by over 70% of the respondents, even though docking is not allowed, and was reported to occur close to a level which was also considered acceptable by the respondents. Most respondents did not think it is probable they would raise tail docked pigs if it were possible, but about 21 % probably would.

These results are important for trying to reduce the risk of tail biting, and subsequently the need for tail docking on an international level.

Results are published in Porcine health management – journal.

More in­form­a­tion

professor Anna Valros, anna.valros(at)helsinki.fi

tel. +358-29-4157400

Managing undocked pigs – on-farm prevention of tail biting and attitudes towards tail biting and docking,

Anna Valros, Camilla Munsterhjelm, Laura Hänninen, Tiina Kauppinen, Mari Heinonen, Porcine Health Management 2016

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

How much straw is enough?

Jensen, M.B., Herskin, M, Forkman, B, Pedersen, L.J., 2015. Effect of increasing amounts of straw on pigs’ explorative behaviour. Applied Animal Behaviour Science 171, 58–63.


  • We investigated the effect of straw amount on pigs’ time spent manipulating straw.
  • We investigated the effect of straw amount on pigs’ simultaneous straw manipulation.
  • Increasing straw from 10 to 430 g/pig/day increased both measures.
  • Increasing straw above approx. 250 g did not significantly increase the behaviour further.


According to European legislation, pigs must have permanent access to sufficient quantity of material to enable manipulation activities. However, few studies have quantified how much straw is needed to fulfil the requirements of growing pigs. We investigated the effect of increasing amount of straw on pigs’ manipulation of the straw, and hypothesised that after a certain point increasing straw amount will no longer increase oral manipulation further. From 30 to 80 kg live weight, pigs were housed in 90 groups of 18 pigs in pens (5.48 m × 2.48 m) with partly slatted concrete floor and daily provided with fresh uncut straw onto the solid part of the floor. Experimental treatments were 10, 80, 150, 220, 290, 360, 430 or 500 g straw per pig and day. At 40 and 80 kg live weight, the time spent in oral manipulation of the straw by three focal pigs per pen (large, medium and small sized) were recorded along with the percentage of pigs manipulating straw simultaneously. This was recorded in three 1-h intervals (1 h before and 1 h after straw allocation in the morning, as well as from 17 to 18 h in the afternoon). With increasing quantity of straw provided, we found a curvilinear (P < 0.01) increase in the time spent in oral manipulation of the straw. Smaller pigs spent more time manipulating straw than larger and medium sized pigs (367, 274 and 252 s/h for small, medium and large sized pigs, respectively; P < 0.001), and pigs spent more time manipulating straw at 40 kg than 80 kg live weight (356 vs. 250 s/h; P < 0.001). At both live weights, pigs spent most time manipulating straw during the hour after allocation of straw. Similar effects of increasing amounts of straw were found for the percentage of pigs engaged in simultaneous manipulation of the straw. Post hoc analyses were applied to estimate the point, after which additional straw did not increase manipulation of straw any further. For the time spent manipulating straw the estimated change point was 253 (approx. 95% confidence limits (CL) 148–358) g straw per pig and day. For the number of pigs simultaneously manipulating straw the change point was 248 (CL 191–304) g straw per pig and day. These results show that increasing the quantity of straw from minimal to approximately 250 g per pig and day increased the time spent in oral manipulation of the straw, as well as the occurrence of simultaneous straw manipulation.
Hence, data from the current experiment identified 250 g straw per pig per day as the amount of straw where a further increase in straw provision did not further increase neither time spent on oral manipulation of straw, nor the percentage of pigs simultaneously manipulating straw. This suggests that, within the current housing system and using this criterion, this amount of straw may be the biological turning point for increasing oral manipulation of straw.