Category Archives: Straw

Just a nice picture of what a pig’s tail should look like

What do you see?

Please have a look at this pig’s tail. You may note that contrary to most EU pigs, this Finnish pig has a curly tail. In addition, please note that this pig does not only has a curly tail. Its tail also has a hairy plume. That is what a pig’s tail should look like: It is the pig’s welfare thermometer.

Curly tail as sign of melting pig-welfare iceberg

The FareWellDock project has accumulated scientific information directed at reducing the need for tail docking in Europe. In this way it has contributed to ending the progressive melting of the pig-welfare iceberg. But sometimes, a picture says more than a thousand words, for the pig’s tail is an iceberg indicator for pig welfare.

Culty pig tail with brush

Curly pig tail (© Mari Heinonen).

Survey on straw use and tail biting on Swedish pig farms

Wallgren, T. R. Westin and S. Gunnarsson, 2016.  A survey of straw use and tail biting in Swedish pig farms rearing undocked pigs. Acta Veterinaria Scandinavica 58:84.


Background: Tail biting is a common problem in intensive pig farming, affecting both welfare and production. Although routine tail docking is banned within the EU, it remains a common practice to prevent tail biting. Straw as environmental enrichment has been proposed as an alternative to tail docking, but its effectiveness against tail biting and function in manure handling systems have to be considered. The aim of the study was to survey how pigs with intact tails are raised and how tail biting is handled in Sweden, where tail docking is banned through national legislation. The study emphasises straw usage and its association with tail biting pigs and problems in the manure handling system. The expectation is that this information could be conveyed to the rest of the EU to reduce the need for tail docking.

Results: In a telephone survey of randomly selected Swedish pig farmers (46 nursery and 43 finishing pig units) with at least 50 sows or 300 finishing places, it was found that straw was used by 98% of the farmers. The median daily straw ration provided was 29 g/pig for nursery and 50 g/pig for finishing pigs in systems with partly slatted flooring. The reported prevalence of tail biting was 1.6% at slaughter. The majority of farmers reported that they never had manure handling problems caused by straw (56% of nursery units and 81% of finishing pig units). A proportion of farmers (37%) also provided with additional material apart from straw on some occasions, which may have affected tail biting prevalence and manure handling problems.

Conclusions: Swedish farmers rear undocked pigs without large problems with tail biting. Straw is the main manipulable material used, and additional manipulable material is used to various extents. The low incidence of straw obstructing the manure handling systems implies that it is indeed possible to use straw in partly slatted flooring systems, reducing the need for tail docking. The impact of using additional manipulable material is unknown and requires more investigation to separate the impact of such material from the impact of straw.

Straw survey in Sweden (3 conference abstracts)

A survey of straw use and tail biting in Swedish undocked pig farms
ICPD 2016, 20-23 June 2016, Wageningen (oral presentation)
T. Wallgren, R. Westin, S. Gunnarsson
Swedish University of Agricultural Sciences, Department of Animal Environment and Health, Skara, Sweden


Tail biting is a common problem in todays’ pig production, affecting production and welfare. As tail biting behaviour is more prominent in systems with no or limited access manipulable material, it has been considered related to exploratory behaviours. Tail docking, commonly used as tail biting prevention, is a painful procedure that can decrease pig welfare does not eliminate the tail biting behaviour. Although tail docking is not accepted as a routine procedure according to the EU Directive 2008/120/EC it is still a common practise within the EU, which is why other measures to reduce tail biting behaviour are needed. In Sweden, tail docking is banned and tail biting must be reduced otherwise. Furthermore, Swedish legislation banned fully slatted floors and demands pigs to have access to manipulable material. In order to investigate the prevalence of tail biting in Sweden and the relationship with provision of straw, we performed a telephone survey in nursery (n=46) and finishing pig (n=43) farms. Farmers were interviewed regarding straw usage (e.g. daily ratios) and tail biting (e.g. frequency). All participating farmers gave access to manipulable material and 98% used straw. The median straw ration reported by farmers was 29g/pig/day (min: 8g, max: 85g) in nursery and 50g/pig/day (9g, 225g) in finishing farms when excluding deep litter systems. Farmers reported having observed tail bitten pigs, at any time, in 50% of nursery and 88% of finishing pig farms. Of these, tail bitten pigs were reported to be found ≤2 times/year (78%), 3-6 times/year(17%) or monthly (4%) in nursery and ≤2 times/year (21%), 3-6 times/year (37%), monthly (34%) or weekly (8%) in finishing farms. Finishing farmers reported on average 1.6% tail bitten pigs/batch (0.1-6.5%), which is in line with abattoir data. Spearman rank correlation was used for statistical analysis. Increased straw ration was correlated with decreased reported tail biting frequency in finishing farms (r=-0.39, P=0.03, n=31), and a tendency for this was found in nursery farms (r=-0.33, P=0.08, n=29) when deep litter systems were included. In finishing farms, excluding deep litter systems, an increased tail biting frequency observed by farmers was correlated to the percentage of tail bitten pigs (r=0.64, P=<0.001, n=33), indicating that an increased frequency of tail biting reported may be associated with more pens affected at outbreaks. Even though provided straw rations were quite small (i.e. 30-50 g/pig/day), this amount of straw may provide pigs with enough occupation to limit tail biting outbreaks. We conclude that tail biting can be kept at a low level (ca 2%) in partly slatted flooring systems, without tail docking, by supplying straw.

Raising undocked pigs: straw, tail biting and management
ISAE 201612-15 July 2016 (poster presentation, see below)
Torun Wallgren, Rebecka Westin and Stefan Gunnarsson
Swedish University of Agricultural Sciences, Department of Animal Environment and Health, Skara, Sweden


Tail biting in pigs is common in pig production and has been suggested correlated to several behaviours. It is associated with reduced welfare and production losses. A common practice to reduce tail biting within EU is tail docking where part of the tail is removed; a painful procedure that does not eliminate the behaviour. According to the EU Directive 2008/120/EC routine tail docking is banned and other measures to reduce tail biting must replace docking. An alternative is to improve the pig environment by using straw and thus decrease development of tail biting. Straw usage has been difficult to implement since it is argued that straw provision is incompatible with fully slatted floors. In Sweden, tail docking and fully slatted floors are completely banned through national legislation. Furthermore, it is a legal requirement that pigs should have access to manipulable material. The implementation of straw usage in Swedish farms was investigated in a telephone survey to study straw usage and farmers’ opinion on straw impact on tail biting and farm management. A total of 46 nursery and 43 finishing farmers were interviewed, all reporting providing pigs with enrichment material, most commonly straw (98%). Median straw rations provided in systems with partly slatted floor was 29 g/pig/day (8-85 g) in nursery and 50 g (9-225 g) in finishing farms. Straw was the only manipulable material in 50% of nursery and 65% of finishing farms while remaining farms used additional material, most commonly wood shavings (65%). ‘Toys’, e.g. balls and ropes, were used by 13% of nursery and 16% of finishing farmers as a supplement to other manipulable material. Of these, 62% only provided these ‘toys’ occasionally, e.g. at re-grouping or when tail biting had been observed. Problems in the manure handling systems caused by straw had occurred in 32% of the farms, of these 25% had problems at yearly and 7% monthly, or more seldom (58%). Tail biting had been observed in the production at least once by 50% of nursery and 88% of finishing farmers, an average of 1.6% finishing pigs were reported tail bitten per batch (0.1-6.5). Tail biting was observed ≤twice/year (78%) 3-6 times/yr (17%) and monthly (4%) by nursey and ≤2 times/yr (21%), 3-6 times/yr (37%), monthly (34%) and weekly (8%) by finishing farmers. The provided amounts of straw seem to be sufficient to keep tail biting at a low level in undocked pig herds (<2%/batch). The low incidence of straw obstruction in manure handling systems reported also implies that straw usage at this rate 30-50 g/pig/day) is manageable in pig production systems.

Production of undocked pigs, a survey of farmers’ experiences
EAAP Annual Meeting, 29 August – 2 September 2016, Belfast (oral presentation)
T. Wallgren, R. Westin, S. Gunnarsson
Swedish University of Agricultural Sciences, Department of Animal Environment and Health, Skara, Sweden


Tail biting is a common cause for reduced welfare and production rates within commercial pig production and is more prominent in barren environments. Using enrichment as straw has been shown to reduce tail biting behavior and thus reduce need for tail docking. Implementation of straw in practice has however partly default since it is argued that straw will cause obstruction in the manure handling systems. Sweden has a long tradition of rearing undocked pigs with access to straw due to national legislation banning docking and fully slatted floors while demanding access to manipulable material for pigs. We surveyed 60 randomly selected Swedish nursery and finishing pig farmers’ usage of straw and their opinions on straw impact on tail biting and manure handling management. All farmers provided manipulable material, 98% straw. In 50% of nursery and 35% of finishing farms the straw was complemented with material such as wood shavings. Straw rations were 29g/pig/day (8-85g) in nursery and 50g (9-225g) in finishing farms. Straw was commonly chopped (76%) to a mean length of 6 cm (1-10) in nursery and 8 cm (1-20) in finishing farms. Straw causing problems in the manure handling system occurred in 32% of the farms who experienced this yearly (25%) or monthly (7%). Most common causes were straw making the slurry sluggish, stacked in pivot or blocking slats. The low incidences of problems indicate current systems are able to cope with presented straw rations. Tail biting had been seen at least one time ever in 50% of nursery and 88% of finishing farms. Frequency of observed tail biting was ≤twice/year (78%) 3-6 times/yr (17%) and monthly (4%) by nursey and ≤ 2 times/yr (21%), 3-6 times/yr (37%), monthly (34%) and weekly (8%) by finishing farmers. An average of 1.6 (0.1-6.5) finishing pigs were reported tail bitten each batch. In partly slatted flooring systems a correlation was found between increased tail biting frequency and percentage of reported tail bitten pigs (r=0.64, P= <0.0001, n=38) (Spearman Rank correlation). The limited tail biting problems indicate that straw usage at this level is enough to prevent major tail biting outbreaks in undocked pigs.

Poster straw survey Sweden

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.

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

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)

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