Tag Archives: Straw

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.

Soundbites Pig Welfare Conference: 2. Presentations

On 29 – 30 April 2015 Danish Minister for Food, Agriculture and Fisheries, Dan Jørgensen hosted an international conference “Improving Pig Welfare – what are the ways forward?“.

During the two-day conference, top academics, experts and political stakeholders from around the world debated and worked to prepare the way forward in improving pig welfare in Europe and ultimately in the world.

Below you find ‘soundbites’ from conference presentations, all more or less related to the subjects of study in the FareWellDock project.

The Welfare Challenges Facing The Pig Sector
Peter Stevenson, Chief Policy Advisor of Compassion in World Farming, UK
Interview (video):
We have created a society where farmers’ margins are so low that they often have no choice but to have very low welfare (P. Stevenson)
We need to find a way in which we can make moving to higher welfare economically viable (P. Stevenson)
The EU should protect farmers from low welfare imports (P. Stevenson)
Most pigs in EU are given no enrichment or ineffective objects such as chains. … Plastic chewing sticks & balls are not effective enrichment (P. Stevenson)
An intact curly tail may well be the single most important animal-based welfare indicator in finishing pigs (EFSA update 2011, cited by P. Stevenson).
The average benefit of raising uncastrated pigs is around €5 per pig due to better feed conversion (EC, 2013, cited by P. Stevenson)
Consumers can drive animal welfare improvements – Don’t keep them in the dark (P. Stevenson).

Could Animal Production Become a Profession?
David Fraser, Professor, University of British Columbia, Canada
Interview (video):
Could pig producers function more like professionals and less like an industry? Professionals set their own standards. (D. Fraser)
The best common people are the agricultural population, so that it is possible to introduce democracy as well as other forms of constitution where the multitide lives by agriculture or by pasturing cattle. Aristotle, “Politics” (cited by D. Fraser).
In the past half century, animal agriculture in the U.S. has been taken over by corporations, turning family farms into factory farms (Farm Sanctuary, 2009, cited by D. Fraser).
Farm animal health levels: Piglet deaths: 0-50%; bursitis: 0-83%; sow mortality: 0-20%; dairy cow lameness 0-85%; broiler lameness: 0-90% (D. Fraser).
Animal welfare reforms have been modeled on worker welfare legislation that regulated the physical environment and exposure time in factories (D. Fraser).
Shifting animal production toward a professional model is a more promising approach to improving animal welfare and maintaining public trust in animal producers (D. Fraser).

Assessment and Alleviation of Pain in Pig Production
Sandra Edwards, Professor, Newcastle University, UK

Sandra Edwards
Sandra Edwards, Professor, Newcastle University, UK

Interview (video):
We need a very strong ethical justification for continuing farm-management procedures which are painful to animals, and look very actively for ways to reduce their necessity (S. Edwards)
Is castration necessary? Not all countries now think so (Backus et al., 2014), but sometimes it may be (S. Edwards)
What links castration, tail docking and gastric ulcers in pigs? Pain (S. Edwards)
Tail docking: Historically (and often currently): A surgical procedure carried out on young piglets with no pain relief (S. Edwards)
Does Tail docking Cause Pain? Many farmers believe not (or only insignificant) (S. Edwards)
30% of finishing pigs and 50% of culled sows have gastric sulcers (score >6). Gastric ulcers are acutely painful in humans. (S. Edwards)
Conclusion: The occurrence of pain compromises animal welfare
– It must be actively addressed.
– “Suppress, Substitute, Soothe”
(S. Edwards)
A reliable method for on-farm pain assessment is needed (S. Edwards)

Neonatal Piglet Mortality in Relation to Sow Farrowing Environment
Lene Juul Pedersen, Senior Researcher, Aarhus University, DK

Lene Juul Pedersen
Lene Juul Pedersen, Senior Researcher, Aarhus University, DK

Interview (video):
Genetic selection for increased littersize in Danish pig production has resulted in problems with piglet mortality that need to be solved, either by changing the breeding goal (to heavier piglets) and/or intensified piglet care (L.J. Pedersen).

Increased piglet mortality is not an innate problem of farrowing pens where sows can freely more around (L.J. Pedersen).
Piglets are born in a thermally insufficient environment (L.J. Pedersen).

Animal welfare in organic pig production
Jan Tind Sørensen, Professor, Aarhus University, DK
Interview (video):
Organic pig production does well on naturalness, welfare perception and low antibiotics use, but needs to solve problems with piglet mortality, endoparasites and castration (J.T. Sørensen).
Scientists cannot solve animal welfare. Politicians either. We need to collaborate to improve pig welfare (J.T. Sørensen).
Lameness prevalense in organic sow herds is higher during summer (Knage-Rasmussen et al 2014, cited by J.T. Sørensen).
High piglet mortality in organic pig production (Sørensen & Pedersen 2013, cited by J.T. Sørensen)
Organic pigs may be more resistant to Salmonella infections
(Bonde & Sørensen 2012, cited by J.T. Sørensen)

The Intelligent Pig Barn
Anders Ringgaard Kristensen, Professor, University of Copenhagen, DK
Interview (video):
Sensor technology is one of the ways forward in pig production (A.R. Kirstensen)
The intelligent pig barn – PigIT – Welfare problems considered: diarrhea, fouling and tail biting (A.R. Kirstensen).

The Danish Pig Welfare Action Plan
Per Henriksen, CVO, Danish Veterinary and Food Administration, DK

The use of animal welfare indicators
Jeremy Marchant-Forde, Research Animal Scientist, USDA-ARS, USA
Interview (video):
Scientists in the EU interact more with policymakers, while the US has closer links with producers (J. Marchant-Forde)
From 2005 to 2050 the global demand for meat will raise: poultry from 82 to 181M tonnes, beef from 64 to 106M, and pork from 100M to 143M tonnes (43%) (J. Marchant-Forde).

The Danish Animal Welfare Index Project
Björn Forkman, Professor, University of Copenhagen, DK
Interview (video):
The Danish Animal Welfare Index is animal-based, compares welfare across years and is based on a definition of welfare in terms of feelings (B. Forkman)
The Danish pig welfare conference showed an astonishing interest in pig welfare (B. Forkman).
“Happy pigs are dirty” (B. Forkman)

Ethical Meat Production & Consumer Response
Athanasios Krystallis Krontalis, Professor, Aarhus University, DK
Interview (video):
What people believe, sometimes is irrevant to the way they behave (A.K. Krontalis)

The social desirability effect implies that we tend to stay on the safe side, hiding what we really believe about something and simply reproducing stereotypes. So people have difficulty saying I don’t care about animal welfare (A.K. Krontalis).
It will take a lot of effort to reveal the real opinions of people generally [regarding animal welfare] (A.K. Krontalis).
29.149 food products launched with the claim “ethical” on their description (top-10 categories, all European countries) (Mintel Gnpd, Apr. 2013 cited by A.K. Krontalis).
Around 4,000 new food product launches with the term “Animal welfare” in their description. Mintel Gnpd, Apr. 2013 (cited by A.K. Krontalis).
People with weak attitudes to pig production eat somewhat more pork (A.K. Krontalis).
Not eating pork at all is not related to being critical to pork production (A.K. Krontalis).
consumers seek more information about production methods to make informed choices (Harper & Henson, 2001, cited by A.K. Krontalis)
In a EU survey (2005) consumers stated they are very rarely or never able to identify meat products from sustainable production methods (cited by A.K. Krontalis)
Ethical meat can be achieved by:
* Optimization of current production (consumer-driven)
* Development of new (technology-driven) production (i.e. in-vitro or insect-based), with questionable social acceptance potential (A.K. Krontalis).

Good welfare is good business
Jeremy Cooper, CEO, Freedom Food and Kate Parkes, Senior Scientific Officer, RSPCA, UK
Good welfare is good business (J. Cooper, CEO Freedom Food)
Freedom Food: > 3.5k members, 1 billion terrestrial farm animals, > 2k labelled products, almost 1/3 of UK pigs, 50% of UK eggs, > 70% of Scottish salmon (J. Cooper)

The effects of stockperson education and training on farm animal welfare
Paul Hemsworth, Professor, University of Melbourne, Australia
Attitudes tend to direct our behaviour or, at least, our intended behaviour (P. Hemsworth).
The best way to predict how stockpeople will interact with their animals is by knowing what their attitude is toward the activity itself (P. Hemsworth).
To target ‘stockmanship’ both technical and behavioural training of stockpeople are necessary! (P. Hemsworth).

Soundbites Pig Welfare Conference: 3. Workshop

On 29 – 30 April 2015 Denmark hosted an international conference “Improving Pig Welfare – what are the ways forward?“.

During the two-day conference, top academics, experts and political stakeholders from around the world debated and worked to prepare the way forward in improving pig welfare in Europe and ultimately in the world. Ministers from the Netherlands, Germany and Sweden participated.

Below you find ‘soundbites’ from conference workshops, all more or less related to the subjects of study in the FareWellDock project.

Workshop 3: Tail docking of piglets

The workshop on tail docking of piglets at the Pig Welfare Conference in DK had a very interesting poll showing that 95 % of the participants believe that it is realistic to stop tail docking either immediately or within a 10 years period.

Suggested solutions and ways forward for pig welfare (from Workshop 3): Stopping tail docking immediately …and encouraging the farmer to think “out of the box”; sharing information regarding manipulative material.

Workshop presentations:

Torben Jensen, Chief Manager, SEGES, Danish Pig Research Centre:
Intact Tails – A Challenge!
To dock or not to dock – what is in the producer’s best interest? (T. Jensen)
THE UNDERLYING PROCESSES OF TAIL BITING: foraging activity and tail damage are central (T. Jensen, Slide 3)
ENRICHMENT materials’ relative effect at reducing tail biting (D’Eath et al. 2014): 500gr compost/d is better than 500gr straw, but the latter may be equivalent to 12.5-20gr/p/d (T. Jensen, Slide 4)
Standard Undocked may pay off for some farmers but it is a more risky choice and has inferior welfare to Standard Docked (T. Jensen)
Cessation of tail docking increases the incidence of tail biting even in well-managed herds (T. Jensen)
Tail lesions are more frequent in organic and free range production than in conventional production (T. Jensen)
By tail docking producers are acting in their own best interest (T. Jensen)
To compare welfare consequences of no docking at a farm level the number of tail bitten pigs must be considered (T. Jensen).

Workshop 5: Market driven animal welfare. The role for retailers and consumers

Hans Spoolder, Professor, Wageningen University:
EconWelfare: Upgrading Animal Welfare Standards Across Europe
We need transparent animal welfare labeling schemes (H. Spoolder)
EU wide legislation is important to set the lower boundaries for farm animal welfare, and it needs to be enforced (H. Spoolder).
The overall goal of animal welfare policy should be the same everywhere in the EU (H. Spoolder).

Saving the pig tail

Anna Valros and Mari Heinonen published a paper called “Save the pig tail” in Porcine Health Management.


Tail biting is a common problem in modern pig production and has a negative impact on both animal welfare and economic result of the farm. Tail biting risk is increased by management and housing practices that fail to meet the basic needs of pigs. Tail docking is commonly used to reduce the risk of tail biting, but tail docking in itself is a welfare problem, as it causes pain to the pigs, and facilitates suboptimal production methods from a welfare point-of-view. When evaluating the cost and benefit of tail docking, it is important to consider negative impacts of both tail docking and tail biting. It is also essential to realize that even though 100% of the pigs are normally docked, only a minority will end up bitten, even in the worst case. In addition, data suggests that tail biting can be managed to an acceptable level even without tail docking, by correcting the production system to better meet the basic needs of the pigs.

Valros, A., M. Heinonen, 2015. Save the pig tail. Porcine Health Management 2015 1:2.

Straw reduces piglet mortality at farrowing related to starvation and stillbirth

This post presents the highlights and abstract of a paper by Westin et al.:

Westin, R., Holmgren, N., Hultgren, J., Ortman, K., Linder, K., Algers, B. In press. Post-mortem findings and piglet mortality in relation to strategic use of straw at farrowing. Prev. Vet. Med.


• Post-mortem examination was performed in 798 piglets from 363 litters.
• The major post-mortem findings were starvation (34%) and crushing (28%).
• Fewer piglets starved to death in STRAW compared to CONTROL-litters.
• Strategic use of straw reduced the number of stillborn piglets by 27%.


Piglet survival is the outcome of complex interactions between the sow, the piglet and
their environment. In order to facilitate nest-building and to provide a suitable environment  for the newborn piglets, a strategic method to supply loose housed sows with large  quantities of straw at farrowing has been developed by Swedish piglet-producing farmers.  The objectives of this cohort study were to use post-mortem findings to assess the causes of death and to quantify the effect of a large quantity of straw provided before farrowing compared to limited small daily amounts on stillbirths, post-mortem findings in piglets dying within 5 days after birth and the pre-weaning mortality. On each of four commercial piglet-producing farms in South-West Sweden, one batch of sows was studied during two consecutive lactations. At inclusion, sows were randomly assigned to two treatment groups, and sows remaining in the batch during the next lactation switched treatment group. In the STRAW group (n = 181 litters) sows were provided with 15–20 kg of chopped straw 2 days prior to the calculated date of farrowing. Sows in the CONTROL group (n = 182 litters) received 0.5–1 kg of chopped straw on a daily basis plus about 2 kg for nest-building when the stockperson judged the sow to be about to farrow. After onset of farrowing, additionally 1–2 kg was given. Post-mortem examination was performed in all piglets that died within 5 days after birth (n = 798). The three major post-mortem findings were starvation (34%) crushing by the sow (28%), and enteritis (24%). In conclusion, strategic use of large quantities of straw reduced the number of stillborn piglets per litter by 27% (p = 0.007). Under the conditions studied, the pre-weaning mortality of liveborn piglets was not affected by treatment; however, the distribution of post-mortem findings differed with fewer piglets dying due to starvation and more due to crushing and enteritis in STRAW litters.

Newborn piglet
Newborn piglet (Photo by Rebecka Westin)

Straw promotes nestbuilding and facilitates farrowing

This post presents the highlights and abstract of a recent paper by Westin et al.:

Westin, R., Hultgren, J. Algers, B. In press. Strategic use of straw increases nest building in loose housedfarrowing sows. Appl. Anim. Behav. Sci.


• Nest building behaviour and farrowing duration were studied in 138 sows.
• A large quantity (15–20 kg) of straw given once was compared to small daily amounts.
• Time spent nest building during 18 h pre-partum was increased by 19%.
• A 1-h increase in time spent nest building reduced the farrowing duration by 12%.


In spite of domestication, sows are still genetically programmed to perform nestingbehaviour close to farrowing. In order to facilitate nest building, a method for a strategic useof large quantities of straw has been developed by Swedish piglet producing farmers. Theobjectives of the present study were to quantify the effect of strategic use of 15–20 kgof chopped straw given once 2 days prior to expected date of farrowing, compared tosmall daily amounts (0.5–1 kg) and 2 kg close to farrowing (controls), on the nest buildingbehaviour and the duration of farrowing. The behaviour from 18 h pre-partum until 1 h afterbirth of first piglet and the duration of farrowing was continuously observed in 138 videorecordings from 4 commercial farms. On each farm, 20–34 sows (parity ≥ 2) were stud-ied during one or two consecutive lactations. Compared to controls, strategic use of strawtriggered the sows to start nest building earlier and increased the total time spent nestbuilding pre-partum by 19% (p = 0.039). Sows given large amounts of straw also performedless nesting behaviours during the first hour after birth of the first piglet. This shows thatnest building is affected not only by the presence of straw, but also by the quantity of strawprovided, and that 2 kg of chopped straw seems to be too little to make the sow terminatenest building well in advance of farrowing. There was no significant effect of treatment onthe duration of farrowing but a strong negative association was found between time spentnest building pre-partum and the duration of farrowing regardless of treatment. The modelpredicted a 1-h increase in total nest building time pre-partum to be associated with a 12%(95% CI = 4–19%) shorter duration of farrowing (p = 0.004).

Nestbuilding sows
Nestbuilding sow (Photo by Rebecka Westin)
Farrowing sow and piglets on straw (Photo by Rebecka Westin)
Farrowing sow and piglets on straw (Photo by Rebecka Westin)

Throughput capacity of straw on slatted floors

Providing straw is a well-known obstacle for use on slatted floors because as the straw may rapidly get out of reach of the pigs by falling through the slats and because the straw may block the liquid manure handling system. Research in Sweden investigates the throughput capacity of straw for nestbuilding in farrowing sows and for reducing tail biting in weaned and growing-fattening pigs.

Nest-building behaviour is regarded as a behavioural need for the pre-partum sow and sows in modern pig husbandry are highly motivated to perform this behaviour. A sow that lacks possibilities to perform foraging and nest-building behaviour at farrowing will be frustrated and stressed, which can result in reduced piglet survival or savaging of piglets. Thus, sows should be provided with appropriate substrate to perform nest-building behaviour at farrowing.
Furthermore, many newborn piglets in modern pig production develop lameness and poor claw health due to poor floor quality. Lame piglets often need medical treatment and have a reduced growth rate. The claws of newborn piglets have an extremely soft horn tissue making them vulnerable to bruising in early life. However, a few days after birth, the horn tissue becomes harder and more resistant to injury. Provision of straw as bedding only during the first week of life might therefore be sufficient to reduce the incidence of lesions. Straw bedding is also a source of thermal insulation, found to be suitable for the prevention of prolonged hypothermia in newborn pigs. Piglets with a low body temperature are more likely to die from infections or crushing. Provision of straw to newborn piglets may increase their welfare by decreasing the risk of lameness and/or hypothermia.
In a Swedish study a strategic usage of straw was investigate in two commercial piglet producing farms. The ability of straw to drain through slatted flooring was studied giving the sows 15 kg of chopped straw around the time of farrowing. In total 96 sows were studied and all sows were loose housed in partly slatted farrowing pens (plastic or cast-iron slats). Chopped wheat straw of three different lengths was compared. The mass median straw lengths were 39, 70 and 130 mm, respectively. It was found that by Day 4 after farrowing straw with short and medium chop length was completely absent in 83% (plastic slats) and 85% (cast-iron slats) of the pens. However, at Day 4 straw was absent in only 6-7% of the pens provided with the longest straw category.
The conclusion from the study is that it is technically feasible to maintain good pen hygiene in partly slatted farrowing pens, even if the sows are provided with 15 kg of chopped straw at farrowing. However, straw chop lengths need to be adjusted to the type of slatted flooring used.

Farrowing sow in straw nest (Photo by Rebecka Westin)
Farrowing sow in straw nest (Photo by Rebecka Westin)

When these results are applied to the objective of using straw as enrichment for growing pigs and to counteract tail biting, the paper shows that it is possible to use straw cleverly and adapt the straw structure to the slatted floor. Optimal is that we give the pigs straw of a structure that enhances their litter related behaviours, but at the same time remains manageable for the farmer and the manure system. This study shows that chopped wheat straw of mass median lengths between 39 and 70 mm can be managed in a slatted system. The paper also evokes the thought that the amount of straw could be varied according to the behavioral needs of the growing pigs, e.g. more straw could be provided to the pigs when they are put into to a new compartment after weaning. Ideally, it could also be possible to develop a monitoring system of early warning of impending tail-biting outbreaks and then increase the amount of straw given to the pigs to counteract (and hence prevent) the outbreak. This could be partly automatic (precision livestock farming).

Farrowing sow and piglets on straw (Photo of Rebecka Westin)
Farrowing sow and piglets on straw (Photo of Rebecka Westin)

Some further questions
* To what extent was the straw remaining available to the pigs, e.g. what % is lost through the slats and for how long is it visible in the pen?
The straw (15 kg) was given 2 days prior to expected farrowing and the remains were scored 6 days later (i.e. four days after farrowing). Plastic slats dimensions were: slat width 15 mm, opening width 10 mm, opening length 36 and 84 mm. Cast iron slats: slat width 11mm, opening width 11 mm and opening length 200 mm.
In plastic-slatted pens (i.e. on Farm A), bedding was completely absent (0 kg) on Day 4 in 25 of 30 pens (83%) when provided with straw of short or medium chop lengths compared to 1 of 15 pens (7%) provided with long straw. Similar figures were seen on Farm B which had cast-iron slatted pens, where bedding was absent in 22 of 26 short/medium straw pens (85%) and 1 of 17 long straw pens (6%), respectively. On Day 4 after farrowing, 37 of 43 cast-iron pens (86%) were completely dry and clean on the solid floor. This was the same for the plastic-slatted pens provided with bedding of short or medium straw. However, in plastic-slatted pens provided with bedding of long straw, hygiene became worse over time.

* To what extent did the manure system get blocked, both in the short term and long term?
It was never blocked as the sow and the piglets were degrading the straw over time. In this case 15 kg was given once to the sows for the 6 days. After that, from Day 4 after farrowing and onwards, a small amount of chopped straw (~0.5 kg) was given daily according to the farms’ regular management practice. Weaning was performed after 5 weeks. For the total suckling period it was ~35 kg of straw used.

* What remains to be done in the FareWellDock project?
We will investigate the straw amount and the length that could be used to find an optimum level for usage in semi-slatted pens for growing-fattening pigs. The optimum is where enough straw is provided to minimise the risk of tail and ear biting, while pen hygiene and manure system continue to function at acceptable levels to the farmer. We will start with a survey in Sweden to investigate this further.

Background paper: R. Westin , N. Holmgren , B. Mattsson and B. Algers, 2013. Throughput capacity of large quantities of chopped straw in partly slatted farrowing pens for loose housed sows, Acta Agriculturae Scandinavica, Section A – Animal Science

Sow and piglets on straw
Sow and piglets on straw

See also:
Westin, R., Holmgren, N., Hultgren, J. and B. Algers, 2014. Large quantities of straw at farrowing prevents bruising and increases weight gain in piglets. Preventive Veterinary Medicine 115: 181-190. doi: http://dx.doi.org/10.1016/j.prevetmed.2014.04.004.
Westin, R. 2014. Strategic Use of Straw at Farrowing – Effects on Behaviour, Health and Production in Sows and Piglets. PhD thesis, SLU, Skara.

•Strategic use of large quantities of straw effectively prevents piglets from developing skin abrasions and claw lesions.
•The overall prevalence of skin and claw lesions was reduced by at least 50% in STRAW compared to CONTROL piglets.
•Average daily weight gain until 5 days of age increased by 25 g in the STRAW treatment.
•Mean body weight at weaning increased by 0.33 kg

Branched chains as enrichment for pigs (technical description, pictures and video)

This post illustrates the so-called branched chain design. This is an improved type of chain that seems most suited as a starting point towards providing proper enrichment (as required by e.g. EU legislation) for conventional, intensively-farmed pigs. However, also pigs on straw may benefit from such chains. Below the description of the branched chain design you can find some pictures and video clips of branched, anchor-type chains for pigs (conventionally-housed weaners and growing fattening pigs, and gilts kept on straw).

Specification of the branched chain design

1: Object-design: A branched chain consists of a vertically-positioned long chain with its end resting on the solid floor over a distance of 20 cm. Two or three additional chain ends (branches) end at or slightly below the nose height of the smallest and middle-sized pigs reared in the pen.
2: Material: The chains are stainless-steel anchor chains (for at least the last 5-10 links of each chain end). Recommended dimensions are 7mm for growing-fattening pigs, 5-6 mm for weaners, 4-5 mm for piglets and 8 mm for sows.
Anchor chains have links which are more round and heavier than the cheaper, more oval-shaped c-chains. Note that the indicated sizes refer to the diameter of the metal, not the diameter of the links. For example, a 7 mm anchor chain for finishers has links measuring 36×23 mm.  Preferably various chain sizes should be provided in the pen, esp. when the pen may contain pigs of variable sizes (e.g. from 25 to >100 kg). Stainless-steel anchor chains are more expensive, but only the last 5 or so links need to be replaced when worn e.g. every 5 – 10 years.
3: Availability and placement: One branched chain is provided for every 5 pigs.The chains are spaced apart as much as possible, preferably with at least one pig length between 2 branched chains in a pig pen. The branched chains are attached at the top end of the pen wall, over the solid floor, and not in the dunging area.

The description of the branched chain design was derived from: Bracke MBM, 2017. Chains as proper enrichment for pigs (incl. supplement). In: Spinka M, editor. Advances in Pig Welfare: Elsevier.

Table. Anchor-chain link dimensions

Chain link thickness (mm) Length (mm) Width (mm)
4 26.5 16
5 ~28 ~17.5 (estimate)
6 30 19
7 36 23
8 40 26
9 ~44 ~30 (estimate)
10 48 34

Pictures of branched anchor-type chains

Short chain and ball. Note the bite marks on the ball. The ball is hanging on a c-chain (oval shaped). The short chain resembles an anchor chain but isn’t (links not massive enough). Short chain, ball and branched chain made of suboptimal c-chain links. This type of branched chain uses only 1 fixation point (reducing costs). Branched anchor-type chain with 3 branches. Only top left branch is made of c-chain in order to ‘test’ pig preferences for the anchor-type chains (top right branch).
Four stainless-steel anchor chains. Two middle chains are worn by long-term use (5-10 years). Outer chains show original shape. Branched chain provided to weaned piglets Occasionally a pig will be reaching up. But normally they show downward-directed behaviour.
Branched chain for fatteners Most manipulation of the branched chains is floor directed. Both rooting and biting/chewing/playing.
Floor directed ‘rooting’. The pig’s nose really ‘fits’ a floor-directed orientation.
Also some more horizontal chewing Sometimes more pigs are interested in the same thing.
Side-way chewing (fits into cheek fold for canine teeth). Taking a whole branch (10 links) into the mouth. Three pigs all at once.
Some occasional pulling. Empty straw-bricket container. The floor plate may be used to keep a chain from getting stuck in the slats and/or repair when the floor below the branched chain gets worn. Gilt in a straw pen next to a branched chain between the lying area (front) and dunging area in the back of the pen.
Floor-directed chain manipulation may be labelled ‘rooting’ …  …not just because there is also some straw…  …it resembles stone chewing seen in outdoor sows.
A second branched chain in the same pen containing four gilts. Grabbing the chain horizontally, showing the cheek fold. A branched chain in another pen containing two gilts on straw.
Floor directed behaviour Biting the chain occasionally. Fixation of the floor chain using the right front leg. True ‘manipulation’ (as manus in Latin means ‘hand’).
Branched chain worn temporarily as an ‘ear ornament’. Two gilts playing with the branched chain at the same time. Anchor-chain links worn (right) by pig manipulation.





These pictures may be used for non-commercial purposes & publications provided copy-rights (MB) are acknowledged.

The video clips below show the pigs in action.

This video shows that a hockey-type ball may be frustrating for pigs, and that the branched chain design is much more appreciated, even by organic pigs.

Related posts:

Chains as enrichment for pigs (Book chapter with supplement)
Ketting als hokverrijking voor varkens (incl. link naar het supplement)
Pig animation – Improved, branched chain design as proper enrichment for pigs
Branched chains as enrichment for pigs (technical description, pictures and video)
Proper enrichment for intensively-farmed pigs – From review to preview
A collection of pictures of other enrichment materials for pigs can be found here: Prize contest (Prijsvraag) 2011.
Do pigs play with chains? Science versus society