EC Directive 2001/93 requires that all pigs have access to proper investigation and manipulation materials. Intensively farmed pigs in Europe are frequently provided with a short/bare metal chain with or without an indestructible object attached to the chain. To date authorities are regarding this as proper enrichment. However, it has become increasingly clear that the chains do not provide proper enrichment, and that adding an indestructible object such as a ball, pipe or hard wood to the end of the chain may even reduce pig welfare. To test this hypothesis an expert survey was conducted. In total 36 international experts, mostly pig-welfare scientists, responded to the survey.
The experts only marginally agreed with the hypothesis (agreement
score 4.6 on average on a scale from 0-10). However, indestructible materials
generally received very low scores for welfare, indicating they did not provide
proper enrichment. Ranked from low to high average welfare score, the objects
were grouped in 5 significance levels:
Level 5 (totally insufficient): Chain hanging too high (for most
of the smallest pigs in the pen; average score 1.3 on a scale from 0 to 10
where 5.5 would be ‘acceptable’)
Level 4 (extremely insufficient): Short chain (3.1), Small
ball (2.8) and Big ball (average 2.5)
Level 3: (very insufficient) Pipe (3.5) and Bare chain (3.3)
Level 2-3 (very/rather insufficient): Hard wood (3.7)
Level 2 (rather insufficient): Chain on the floor (average:
4.4)
Compared to the marginal enrichment provided before the EC Directive 2001/93 was implemented in 2007 (in the Netherlands generally a short/bare chain, scoring 3.1 and 3.3 respectively, i.e. Level 3-4), adding balls or pipe , as commonly done in The Netherlands and Germany, does not improve pig welfare. Hard wood, as practised esp. in the UK, is a most marginal improvement (only 0.4 higher on average than Bare chain). Chain on the floor scored a bit better (4.4), without being acceptable (set at 5.5). The ‘new’ Branched chains scored significantly better than all other indestructible materials and its welfare score (5.1 on average) was close to the pre-defined level of acceptability (5.5 on a scale from 0, worst, to 10, best). The welfare benefits of adding balls, pipes or hard wood to the metal chain were marginal, and well below what the experts considered acceptable enrichment. The branched-chains design, by contrast, appears to be the most viable alternative. It involves providing a longer chain, i.e. with the free end reaching to floor level, adding ‘branches’, i.e. several short chains ending at the nose height of the pigs, and providing more chains per pen (i.e. 1 branched chain per 5 pigs). Therefore, the implementation of current pig-enrichment legislation needs revision. Branched chains should be implemented widely (across the globe) and in the short term as a first step towards, and benchmark for, providing proper enrichment to intensively-farmed pigs.
See also the related publication and posts on this website:
EC
Directive 2001/93 requires that all pigs have access to proper investigation
and manipulation materials. Intensively farmed pigs in Europe are frequently
provided with a short metal chain with or without an indestructible object
attached to the chain. To date authorities are regarding this as proper
enrichment, perhaps with (in)direct reference to the RICHPIG model as a
justification. However, it has become increasingly clear that the chains do not
provide proper enrichment, and that adding an indestructible object to the end
of the chain may even reduce rather than improve pig welfare. To test this
hypothesis an expert survey was conducted containing 26 more or less compound
questions. On a scale from 0 to 10 experts specified their level of agreement
with the hypothesis, the prevalence and welfare scores of nine indestructible enrichment
materials. In total 36 experts, mostly pig-welfare scientists, responded
(response rate: 39%). Indestructible objects are less prevalent in countries
that provide straw (like Sweden and the UK) and outside the EU (US). They are
more prevalent in the Netherlands, Belgium, France and Finland, while the
prevalence seems to be low in Spain. Balls, wood and pipes were provided most
frequently: hard wood especially in the UK (as specified in farm assurance); indestructible
balls and pipes in Germany and the Netherlands. The experts’ score for
agreement with the hypothesis was only 4.6 on average (scale 0-10; n=25). Enrichment
materials, ranked from high to low welfare score, were grouped in 5
significance levels as indicated by different superscripts based on Wilcoxon
signed rank tests: Branched chains (5.1a), Chain on the floor (4.4b),
Hard wood (3.7bc), Pipe (3.5c), Bare chain (3.3c),
Short chain (3.1d), Small ball (2.8d), Big ball (2.5d),
and Chain hanging too high (1.3e). Branched chains scored
significantly better than all other indestructible materials and its welfare
score (5.1 on average) was close to the pre-defined level of acceptability (5.5
on a scale from 0, worst, to 10, best). The welfare benefits of adding balls,
pipes or hard wood to the metal chain were marginal, and well below what the
experts considered acceptable enrichment. The branched-chains design, by
contrast, appears to be the most viable alternative. It involves providing a
longer chain, i.e. with the free end reaching to floor level, adding
‘branches’, i.e. several short chains ending at the nose height of the pigs,
and providing more chains per pen (i.e. 1 branched chain per 5 pigs). Branched
chains should be implemented widely and in the short term as a first step
towards, and benchmark for, providing proper enrichment to intensively-farmed pigs.
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.
Two pigs playing simultaneously with a preferred anchor-type branched chain design.
This post was published originally on the personal website of the first author (see here).
Indirect genetic effects (IGEs) are heritable effects of an individual on phenotypic values of others, and may result from social interactions. We determined the behavioural consequences of selection for IGEs for growth (IGEg) in pigs in a G × E treatment design. Pigs (n = 480) were selected for high versus low IGEg with a contrast of 14 g average daily gain and were housed in either barren or straw-enriched pens (n = 80). High IGEg pigs showed from 8 to 23 weeks age 40 % less aggressive biting (P = 0.006), 27 % less ear biting (P = 0.03), and 40 % less biting on enrichment material (P = 0.005). High IGEg pigs had a lower tail damage score (high 2.0; low 2.2; P = 0.004), and consumed 30 % less jute sacks (P = 0.002). Selection on high IGEg reduced biting behaviours additive to the, generally much larger, effects of straw-bedding (P < 0.01), with no G × E interactions. These results show opportunities to reduce harmful biting behaviours in pigs.
New book: Advances in Pig Welfare
1st Edition
Editors: Marek Špinka
Hardcover ISBN: 9780081010129
Imprint: Woodhead Publishing (Elsevier)
Published Date: 10th November 2017
Page Count: 506
Table of Contents
Part One: Pig Welfare Hotspots
1. Overview of commercial pig production systems and their main welfare challenges* – Lene Juul Pedersen
2. Sow welfare in the farrowing crate and alternatives*
3. Piglet mortality and morbidity: inevitable or unacceptable?*
4. Lifetime consequences of the early physical and social environment of piglets* – Helena Telkänranta, Sandra Edwards
5. Tail biting* – Anna Valros
6. Manipulable materials* – Marc Bracke
7. Mitigating hunger in pregnant sows*
8. Aggression in group housed sows and fattening pigs
9. Handling and transport of pigs
10. Slaughter of pigs
Part Two: Pig Welfare Emerging Topics
11. The pain-sensitive pig* – Mette S Herskin, Pierpaolo Di Giminiani
12. On-farm and post-mortem pig health status assessment
13. Pig-human interactions: Pig-human interactions: creating a positive perception of humans to ensure pig welfare*
14. Breeding for pig welfare; opportunities and challenges*
15. Positive pig welfare
16. Pigs as laboratory animals* – Jeremy Marchant-Forde, Mette S. Herskin
Chapters marked with * have (co-)authors involved in FareWellDock. Chapters with stated authors only have FareWellDock partners as (co-)authors.
Description
Advances in Pig Welfare analyzes current topical issues in the key areas of pig welfare assessment and improvement. With coverage of both recent developments and reviews of historical welfare issues, the volume provides a comprehensive survey of the field.
The book is divided into two sections. Part One opens with an overview of main welfare challenges in commercial pig production systems and then reviews pig welfare hot spots from birth to slaughter. Part Two highlights emerging topics in pig welfare, such as pain and health assessment, early socialization and environmental enrichment, pig-human interactions, breeding for welfare, positive pig welfare and pigs as laboratory animals.
This book is an essential part of the wider ranging series Advances in Farm Animal Welfare, with coverage of cattle, sheep, pigs and poultry.
With its expert editor and international team of contributors, Advances in Pig Welfare is a key reference tool for welfare research scientists and students, veterinarians involved in welfare assessment, and indeed anyone with a professional interest in the welfare of pig. View less >
Key Features
•Provides in-depth reviews of emerging topics, research, and applications in pig welfare
•Analyzes on-farm assessment of pig welfare, an extremely important marker for the monitoring of real welfare impacts of any changes in husbandry systems
•Edited by a leader in the field of pig welfare, with contributing experts from veterinary science, welfare academia, and practitioners in industry
Readership
Animal Welfare research scientists, Postgraduate students, Policy makers and stakeholders, R&D managers
Housing of pigs in barren, stimulus-poor housing conditions may influence their immune status, including antibody
responses to (auto-)antigens, and thus affect immune protection, which will influence the onset and outcome of
infection. In the present study, we investigated the effects of environmental enrichment versus barren housing on the
level of natural (auto-)antibodies (NA(A)b) and their isotypes (IgM and IgG) binding keyhole limpet hemocyanin (KLH),
myelin basic protein (MBP), and phosphorycholine conjugated to bovine serum albumin (PC-BSA) in pigs co-infected
with porcine reproductive and respiratory syndrome virus (PRRSV ) and Actinobacillus pleuropneumoniae (A. pleuro-pneumoniae). Pigs (n= 56) were housed in either barren or enriched pens from birth to 54 days of age. They were infected with PRRSV on 44 days of age, and with A. pleuropneumoniae 8 days later. Blood samples were taken on 7 dif-ferent sampling days. Housing significantly affected the overall serum levels of NA(A)b binding KLH, MBP and PC-BSA, and before infection barren housed pigs had significantly higher levels of NA(A)b than enriched housed pigs, except for KLH-IgM and PC-BSA-IgG. Infection only affected the IgM, but not the IgG isotype. Moreover, changes in MBP-IgM and PC-BSA-IgM following infection were different for enriched and barren housed pigs. These results suggest that the effect of infection on NA(A)b is influenced by housing conditions and that NA(A)b, especially IgM may be affected by infection.
The tendency to reduce crude protein (CP) levels in pig diets to increase protein efficiency may increase the occurrence of damaging behaviours such as ear and tail biting, particularly for pigs kept under suboptimal health conditions. We studied, in a 2×2×2 factorial design, 576 tail-docked growing-finishing entire male pigs in 64 pens, subjected to low (LSC) vs. high sanitary conditions (HSC), and fed a normal CP (NP) vs. a low CP diet (LP, 80% of NP) ad libitum, with a basal amino acid (AA) profile or supplemented AA profile with extra threonine, tryptophan and methionine. The HSC pigs were vaccinated in the first nine weeks of life and received antibiotics at arrival at experimental farm at ten weeks, after which they were kept in a disinfected part of the farm with a strict hygiene protocol. The LSC pigs were kept on the same farm in non-disinfected pens to which manure from another pig farm was introduced fortnightly. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored for 10×10 min per pen per week. The prevalence of ear damage during the finisher phase (47 vs. 32% of pigs, P < 0.0001) and the frequency of ear biting (1.3 vs. 1.2 times per hour, P = 0.03) were increased in LSC compared with HSC pigs. This effect on ear biting was diet dependent, however, the supplemented AA profile reduced ear biting only in LSC pigs by 18% (SC × AA profile, P < 0.01). The prevalence of tail wounds was lower for pigs in LSC (13 ± 0.02) than for pigs in HSC (0.22 ± 0.03) in the grower phase (P < 0.007). Regardless of AA profile or sanitary status, LP pigs showed more ear biting (+20%, P < 0.05), tail biting (+25%, P < 0.10), belly nosing (+152%, P < 0.01), other oral manipulation directed at pen mates (+13%, P < 0.05), and aggression (+30%, P < 0.01) than NP pigs, with no effect on ear or tail damage. In conclusion, both low sanitary conditions and a reduction of dietary protein increase the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare. Attention should be paid to the impact of dietary nutrient composition on pig behaviour and welfare, particularly when pigs are kept under suboptimal (sanitary) conditions.
Tail docking is a well-known practice in pig production, but it is also heavily criticised. An international team of researchers dived into the topic and wondered what its exact effects are on pigs – and what alternatives there are to avoid tail biting….
Note: This article is an approved summary of the Executive Summary which was published earlier this year at http://farewelldock.eu. In future issues of Pig Progress, to be published later this year, several participating researchers in this project will delve deeper into the individual topics they encountered.
The animal’s emotional state, eventually modulated by environmental conditions, may affect cognitive processes such as interpretation, judgement and decision making behaviour. The Iowa Gambling Task (IGT) is a common method to examine decision making behavior in humans in terms of risk avoidance and risk taking that reflects the underlying emotional state of the subject. In the present study, we investigated the influence of environmental conditions on decision-making in pigs. To assess decision making behavior in pigs, the Pig Gambling task has been developed. In this task, the pig can choose between two alternatives. The pigs can make advantageous or disadvantageous choices, where advantageous, low risk choices deliver smaller, but more frequent rewards, whereas disadvantageous, high risk choices yield larger, but less frequent rewards. In the long run, over a series of successive trials, the advantageous choices will yield more reward and less punishment, where punishment consists of delivering reward into the central food trough, but making it inaccessible. After habituation to testing apparatus and testing methods during the course of approximately 4 weeks, all pigs learned to discriminate between the advantageous and disadvangeous alternatives (acquisition phase) at the age of 9 weeks. After a 14-week retention interval, at the age of 24 weeks, retention performance was tested (retention phase). In both phases, 20 trials per day were given to a total of 120 trials. Saliva and hair samples were collected once at the end of both phases for determining cortisol, and body mass was measured at the end of the retention phase. The pigs increased the number of advantageous choices during the course of training. In in the acquisition phase, barren-housed pigs chose the advantageous options more often compared to environmentally enriched pigs. No differences werer found during the retention phase. All pigs made less advantageous choices at the start of the retention phase than at the end of the acquisition phase. The level of hair cortisol was higher in the barren-housed than in the enriched-housed pigs. This difference was more pronounced after acquisition than after retention testing. No other differences were found for cortisol in saliva and hair. The environments did not differentially affect body mass at the end of the study. Summarizing, housing in a barren environment appears to be more stressful than housing in an enriched environment, as indicated by higher hair cortisol levels in barren-housed pigs, but it also improved acquisition of the PGT.
Tail docking is an undesirable mutilation of pigs. Currently virtually all young piglets are docked in conventional farming so as to prevent tail biting later in life. However, throughout Europe efforts are made to reduce tail docking. Often farmers provide additional enrichment to try and prevent tail biting. Nevertheless, stopping the practice of tail docking may, and frequently does, lead to elevated levels of tail biting, resulting in tail wounds. In relation to this farmers and policy makers would like to know what levels of tail biting would be equivalent to tail docking in terms of pig welfare, i.e. how much tail biting can be allowed before deciding it would be better to continue tail docking. But this poses the problem how to weigh the (lack of) welfare involved in tail biting of a grower or finishing pig against the pain of tail docking of young piglets. Is this possible? And if so, how?
Brainstorm
We recently had a brainstorm session on this subject. This is an outline of what we came up with, including a very tentative personal estimate (by MB).
In my personal view when (in the end up to) about 12% of undocked pigs were tail bitten that would be roughly equivalent in welfare to the docking of all piglets. The uncertainty margin, however, is high, at least ranging from 5-25%. The reasoning underlying my estimate is as follows.
Pain
Firstly, piglets are normally docked using hot iron cautery. This is quite painful as it involves applying both heat and rather blunt trauma. The heat kills bacteria and thus may reduce the chance of subsequent infection of the tail wound. Tail biting at a later age, by contrast, is caused by even more (and multiple) blunt trauma (due to biting). It also has a substantially higher likelihood of infection. In addition, there is e.g. fear in the tail bitten pig due to being chased by a biter. Based on this I would say that pain (and stress directly related to tail biting) may roughly be about ten times as high in intensity and about ten times as long in duration, compared to tail docking. This would imply that 1 tail-bitten pig is off-set by about 100 docked piglets as regards the intensity and duration of the pain involved.
Stress
However, animal welfare encompasses more than just pain. An important additional factor is the level of stress which is not directly related to tail biting activity.
Firstly, there may be stress related to the treatment of tail biting, e.g. when biters and/or victims are taken out of the pen (resulting in social isolation and/or fighting). This stressor, however, is partly offset by the enhanced enrichment normally provided to pigs experiencing an outbreak of tail biting (though not all pigs are equally affected by the ‘costs’ and ‘benefits’). Note that there is another, more macabre, offset involving ‘happiness’ too, and that is the excitement experienced by the (sometimes fanatic) biter pigs when a tail-biting outbreak has started. Note also, that this biter ‘welfare’ is at the same time an indicator of the level of (background) stress experienced by pigs leading to this abnormal behaviour in the first place.
A much more important source of stress that must be taken into account, therefore, is related to the general housing conditions to which the pigs are exposed prior to a tail biting outbreak. Tail biting is an unnatural behaviour that is triggered by (some kind of) stress. Pig farmers are aware of this and will try and prevent tail biting by generally improving the housing conditions when they (start to) raise pigs with intact (undocked) tails. Thus the expected level of stress to which the pigs are exposed is likely to be higher in the case of routine tail docking. When farmers stop tail docking they normally provide much better enrichment (rooting material & space). Farmers raising pigs with intact tails will also take other measures to reduce stress, e.g. provide better climatic conditions, better feed and better health care. These stress-reducing measures don’t just apply to the biters or the victims of tail biting. They apply to all pigs in the pen. Furthermore, they don’t just apply during an outbreak of tail biting, but they apply throughout the pigs’ lives. Hence, the reduced stress levels are a major factor reducing the off-set between docking and tail biting based exclusively on pain (and pain-related fear). I would estimate that the improved living conditions may reduce the off-set by at least a factor 10. This would mean that taking into account both pain and stress, 100(%) docked pigs (kept with minimal care and in a more barren environment) could be roughly equivalent to similarly-sized group of pigs with intact tails under enriched conditions and in which 10% of the pigs has been tail bitten.
Tail biting in docked pigs
However, we know that tail biting does not only occur in undocked pigs. It is also seen in docked pigs. Roughly 2% of docked pigs are tail bitten. It seems safe to assume that the level of pain from being tail bitten is roughly comparable in docked pigs and in undocked pigs (though docked tails may be more sensitive and thus less likely to get bitten). Taking this into account would imply that 100 docked pigs of which 2% also experiences tail biting later in life would be having a level of (poor) welfare comparable to 100 undocked pigs of which 12% gets tail bitten. This is about 6 times as much tail biting as the 2% base-line set under conventional docking conditions.
Much uncertainty
It must be emphasised again, however, that this level of 12% tail biting is a very rough estimate. So, a wide safety-margin applies, e.g. 5-25%. This may depend in particular on the quality of enrichment and the extra care provided under non-docking conditions.
Please note, that this post is the result of a brainstorm session only and presents a personal view. It illustrates how systematic reasoning (using principles of semantic modelling) can be used to start to answer this rather important welfare question. I have provided a very rough estimate. For a more accurate assessment more detailed studies would certainly be required, both in terms of more carefully including what is already known and in terms of accumulating more empirical knowledge about what is not known yet. At present the assessment is still very speculative, and meant to illustrate primarily how to in principle deal with the question of what level of tail biting is equivalent to a practice of routine tail docking.
‘Weighing’ a pig ‘manually’
Postscript: Excluded aspects and some feedback from readers
Note that, in my estimate I neglected several (minor) aspects.
Firstly, I neglected the fact that for tail docking piglets must be picked up. This results in stress, both in the mother sow and in the piglets. From an evolutionary perspective the procedure of catching piglets may be equivalent to experiencing capture by a predator. This would mean that the given estimate would be a moderate underestimation. However, tail docking may be performed in combination with other treatments such as iron injection and castration. If so, the additional stress from handling may be relatively minor. Note, however, that castration applies only to males and may be banned in the near future, and iron injection may be given orally as a kind of ingestible compost, or as has recently been shown, may not be necessary at all. Hence, combining such treatments with tail docking has a reducing likelihood.
Secondly, I assumed that teeth cutting will not be practiced to treat an outbreak of tail biting, neither in the docked pigs, nor in the undocked pigs. Or, more precisely, at least I assumed teeth cutting is not practiced in substantially different numbers of pig. Such teeth cutting is painful and illegal, so it could be considered appropriate to ignore the practice. However, if it were practiced more in undocked pigs (which are likely to experience higher levels of tail biting), then it would have a substantial impact on the level of equivalence, pushing the percentage back down again substantially.
A third point to note is that I did not include in the estimate other ethical considerations or our (anthropomorphic) emotional responses. An example of the latter may be related to the amount of blood seen in the pen, the farmer’s level of stress (unpredictability) associated to this, and the potentially adverse economic consequences associated with tail biting. An example of other ethical considerations is the fact that tail docking may be considered to be an infringement of the animals’ integrity or intrinsic value. In such a rights-based moral view tail docking may be considered ethically wrong, regardless of the level of tail biting when tail docking is stopped. Such aspects were excluded because these are aspects not directly related to animal welfare. They are more related to our human perception of ethics and/or human welfare, rather than animal welfare.
Finally, it is most important to emphasise that I have considered steady-state conditions, but realize that all practices are subject to optimisation. The practice of tail docking has already been optimised for over a period of at least 50 year. By contrast, the practice of raising pigs with intact tails still more or less has to enter the phase of optimisation in commercial practice. This implies that substantially higher levels of tail biting may be regarded as acceptable, provided this is only temporary and provided it leads to substantially lower levels of tail biting later on. In other words, it requires that farmers will persist in raising pigs with intact tails and have a chance to learn to deal with it over a certain transition period, both in terms of prevention and treatment of tail-biting outbreaks.
Feedback reader 1:
Regarding the painfulness of tail biting vs tail docking, I find it impossible to guess the relation – especially as tail biting comes in so many forms.
I absolutely agree that a weighing like this is necessary, but I also think it is a bit dangerous to throw out estimates that are not really based on any evidence (or at least you do not present any?), such as the 100 times worse pain experienced by bitten pigs than docked pigs. Also, tail biting is very heterogeneous, from just a small, one-time bite, to a chronic situation, where the entire tail is lost, so the way you estimate the pain simplifies the matter greatly.
As to the expected level of actual tail biting when docking is stopped: I estimate a two-fold increase in tail biting if no docking is performed. Perhaps somewhere between 2- and 4-fold, based on e.g. slaughterhouse data. There may be a 4-fold increase when the housing situation is not improved otherwise – which you also take into account in your text – when applying a non-docking policy the farmer would normally also improve housing conditions, thus reducing the risk further. I certainly agree that when a farm stops docking, they will probably have a higher incidence of tail biting initially, but on the long-term (as is shown e.g. in Finland where tail docking is totally forbidden, and the tail-biting incidence, based on abattoir data is around 2%), a 10 or 12% incidence is certainly higher than I would expect.
Feedback reader 2:
Having read your blog I think you need to factor in adaptive, compensatory pain modulation into your model.
It is sometimes too easy to fail to take into account post-injury peripheral and central modulation of pain signalling that occur as part of the normal healing process and only focus on the ‘pro-pain’ component.
I also don’t see how you can substantiate this claim?
‘Based on this I would say that the pain of tail biting may be about ten times as high and about ten times as long, compared to tail docking. This would imply that 1 tail-bitten pig is off-set by about 100 docked piglets as regards the intensity and duration of the pain involved’.
While I think it might be possible to attribute weighting to some risk factors within systems, I don’t think it can be applied to pain experienced by an individual (or even at group level as you are suggesting) because there are so many factors that contribute to an individual’s experience of pain? I don’t think you can quantify the painfulness of tail biting and tail docking.
Also when thinking about stress you might want to define what you mean by that in relation to chronicity?
Short-term compensatory responses to stress are in my view positive for the animal; however beyond that when there is a failure of compensation and ultimately homeostatic decompensation then they are undoubtedly negative.
I guess I’m suggesting that any weighting approach might need to accommodate (or factor in) changes over time (i.e. dynamic weighting?)
I hope you find my comments helpful?
Reply:
As to substantiation, again, it’s my suggestion for a start of an argument to answer this in my view fairly important question. My answer is based on my personal experience as a vet and scientist, and on reasons indicated in the blog. It is certainly in need of further study, examination and assessment. I fully acknowledge the considerable level of uncertainty as well as the risk associated with trying to answer the question. At the same time, however, I would also argue that there is a considerable risk in refusing to try to answer the question, as this leaves the issue to stakeholders.
Feedback reader 3:
Joining the discussion rather late, but basically I agree with the points others have made. I think it quite reasonable to conceptually set out the trade-offs which would determine the level of tail biting above which tail docking could be ethically justified, but putting numbers on some of these things is rather difficult.
For risk of tail biting in docked and undocked pigs we have a growing number of published sources and comparative national data.
For experimental comparisons we have old data suggesting increases of 30-60% in pigs in unbedded systems.
More recently we have studies suggesting somewhat lower results if straw is given.
So this part is perhaps simple, but depends on your assumptions about which husbandry systems will pertain across Europe.
For the welfare detriment of tail docking and tail biting, data indicate that both have long lasting effects on pain processing pathways, but the implications of this for pain perception for the individual are uncertain.
For tail docking, the data I have seen are still contradictory on whether cautery is more or less painful than simple section (some suggest the cautery destroys the nerves whilst others suggest greater pain). There is also the possibility of tail docking with anaesthesia/analgesia as a route of adoption.
For tail biting, the short term pain will certainly depend on the severity and, even more, on the prevalence of infection. The data on this are currently lacking to my knowledge.
The welfare impairment of keeping in conditions which give rise to tail biting is clearly the greatest of all in magnitude (severity x duration x no of animals) but I don’t think we have any way of comparing the welfare severity of ‘behavioural frustration’ against that of injury/pain. I would be concerned about taking arbitrary figures in the absence of any logical basis.
So, I guess my suggestion would be to explore the framework for this decision, but be very wary about pretending we can quantify it.
I also think the issue not addressed in your blog is the time course of any transition to cessation of tail docking and how to manage this. What proportion of farmers would have the awareness, capital and staff training to implement the changes necessary to their existing housing if obliged to cease tail docking (some older, fully slatted and large group housing systems will pose much bigger challenges and possibly require replacement of buildings), and how long would it take across Europe to reach the ‘acceptable’ situation of relatively low differential in tail-biting prevalence between docked and intact tails, rather than the ‘unacceptable’ differential shown for “one off” change in tail-docking experiments (stopping docking without further improvement of the environmental conditions). I think it important to highlight that your analysis relates to a ‘steady state’ situation and the importance of how any transition is managed and the welfare implications which this will have.
Reply:
Note that I have not been comparing docking versus non-docking in a mono-factorial way. I compared docking in a more barren environment versus not docking in a more enriched environment supplemented with special attention by the farmer, as that is what will normally happen in practice. I have now emphasised this more clearly in the text.
I largely agree that we currently largely lack the data needed to quantify more precisely. However, I also believe that in principle it is possible to do so, and that the estimate/assessment can be more or less verified empirically (as the body of knowledge accumulates and modelling principles are improved). Personally, I am inclined to try and quantify despite considerable uncertainty, because it provides a better starting point for further discussion. In addition, such preliminary but more science-based estimates are much needed to complement the inevitably politically-loaded figures and personal assessments presented by farmer-representatives and NGO’s arguing either (rather exclusively) against or in favour of ending tail docking as a routine practice to prevent tail biting.
An important point I’ve been trying to make is that pain is not the only relevant aspect of welfare involved in tail docking and tail biting, and that the levels of enrichment and care should also be taken into account. I don’t think it is even possible to honestly say it is not possible to ‘add’ these aspects, since proper political decision making (in all kinds of areas, not just tail biting) simply does and has to, whether it is considered scientifically possible or not. And if so, I would argue it is most reasonable to try and provide the best possible scientific support, while being as honest as possible e.g. about uncertainty margins and the relevance of incorporating more information. I also think the estimate provides broad support to ‘farewell-dock’ initiatives such as those in Finland, Sweden, Denmark, the Netherlands, the UK and Germany.
Tail biting constitutes a major welfare and health issue in commercial pig rearing, with significant negative economic consequences. Contrary to the aim of the EU directive (2001/93/EC), tail docking is still widely practiced in most EU countries as a measure to reduce the incidence of tail biting and concomitant pathologies. Mutilations are a general welfare concern in all species, and any efforts towards reducing the need for tail docking are important for the future sustainability of the EU pig sector. Sound policy making needs science-based risk assessment, including assessment of the severity of problems and effectiveness of solutions. The general objectives of the FareWellDock-project included estimation of the relative harms associated with tail docking and tail biting, and evaluation of the efficacy of some main preventive measures against tail biting, which could reduce the need for tail docking. The ultimate aim was to stimulate the development towards a non-docking policy in the EU.
The first objective of WP1 was to evaluate measures of acute and chronic pain in relation to tail damage. This included assessment of the short (acute trauma), medium (post trauma inflammation) and long term (traumatic neuroma formation) pain associated with tail docking in neonatal piglets, and the possible consequences for longer term fear of humans. In addition, the studies assessed the effects of tail-damage in more mature pigs to provide a basis for assessing the pain associated with being tail bitten in later life. Finally, studies were conducted to assess the effects of an NSAID analgesic on the short term responses to neonatal tail docking.
Experimental studies confirmed that piglets do experience pain when tail docked, and that pain relief treatment, such as meloxicam, can lessen but not abolish the physiological stress reaction to docking. Piglets which have been tail docked seem more fearful of people afterwards than undocked animals. In docked tails, no difference in pain sensitivity of the tail (as measured by behavioural withdrawal) is detected after 8 weeks, but changes in the functioning of the sensory nerves from the tail can still be measured after 4 months, which suggests that the possibility for longer term pain exists. When the tail is damaged later in life, as happens with tail biting, changes in both tail stump sensitivity and nerve functioning can last for at least 4 months, and possibly beyond.
WP2 focused on the role of manipulable material when reducing the need for tail docking. The aim was to develop and validate ways to assess if on-farm use of manipulable material is sufficient to reduce tail biting. Further, the aim was to describe suitable methods for implementing the use of straw under commercial farming conditions and to investigate, in on-farm conditions, the efficiency of tail docking vs. enrichment given in sufficient quantity to reduce the occurrence of tail lesions.
A screening method to assess the appropriateness of the level of enrichment on-farm was developed and includes scoring of the amount of unsoiled straw, the behaviour, and ear, tail and flank lesions of the pigs. AMI (animal-material interaction) sensors were used e.g. to show that pigs in biter pens were more interested in novel ropes than pigs in control pens, that environmental enrichment may reduce exploratory behaviour of point-source objects, and that sick pigs, experimentally infected with streptococcus spp, were less interested in chain manipulation. The sensors appear to be a promising tool to assess the use of manipulable material by pigs. In countries (SE and FI) where tail docking is not done, farmers report using on average of 30 to 50 g of straw/pig/ day, equivalent to about 0.5 L/pig/day. A survey in SE revealed fewer injurious tail biting outbreaks on farms using larger amounts of straw. Larger amounts of straw were mainly used on farms having scrapers in the slurry channels. A large experimental study showed that a moderate amount of straw (150 gr/pig/day) reduced injurious tail-biting outbreak in finisher pigs by more than 50%, while docking seemed to be more effective as it reduced tail biting by more than four-fold. The effect of both measures was additive, i.e. docking and straw reduced tail biting 9 fold. Further, it was shown that increasing the amount of straw from 10 to up to 400 gr/pig/day had multiple positive effects by progressively reducing the occurrence of tail injuries and stomach ulcers, increasing growth rate, increasing straw-directed behaviour, and reducing redirected behaviours towards other pigs.
In WP3 the aim was to clarify the role of poor health in the causation of tail biting and victimization, and the aim was study early identification of tail-biting outbreaks. In addition, the aim to develop automated systems for early warning of tail biting outbreaks.
The results of experimental and on-farm studies showed that the social behaviour of sick pigs differs from healthy pen mates, as pigs with osteochondrosis received more sniffing and tail bites from their pen mates than healthy pigs, while pigs with mild respiratory disease tended to bite more at the ears and tails of pen mates than healthy pigs did. In addition, studies of cytokines suggest that low-grade inflammation may decrease activity and increase receiving sniffs and attacks from other pigs. Studies on data sets from commercial pig farms indicated that changes in feeding behaviour may be an important sign of an increased risk for tail biting to occur: Future tail bitten individuals showed a reduced feed intake already 2-3 weeks before tail damage became evident. Furthermore, feeding behaviour in groups which develop tail biting may differ from non-biting groups for at least ten weeks prior to an injurious tail-biting outbreak. It was also shown that tail-chewing activity may start 2-3 weeks before tail damage can be seen. A detailed behavioural study of tail biting events revealed that there appears to be no such thing as a ‘typical’ tail-biting event and that the behaviour shown immediately before a tail-biting event does not differ from behaviour prior to another type of social interaction, namely ano-genital sniffing. Thus, it seems difficult to predict if a social event will escalate into tail biting or not. However, tail biting is more likely between pigs that have previously interacted. Data sets from several countries and studies indicated an association between tail-biting damage and tear staining, but the direction of this association is not clear.
In summary the project concluded on a set of practical recommendations, which have been published as part of four factsheets on the FareWellDock-webpage:
Avoid tail docking whenever possible because it definitely causes pain, induces long-term changes in sensory-nerve function and may impair the pigs’ confidence in humans.
Avoid tail biting, and hence the need for tail docking, by addressing risk factors on the farm.
Treat tail-bitten pigs promptly and consider pain relief.
To reduce injurious tail-biting outbreaks, use straw as it might be almost as effective as tail docking. For this purpose, the more straw the better.
To ensure that sufficient straw is allocated check that there is left-over straw before the next day’s allocation.
Keep your pigs healthy. This will be good both for productivity and also help avoid injurious tail-biting outbreaks.
If pigs show signs of illness, be more alert to tail biting risk.
Remove tail-bitten pigs promptly to avoid further damage and treat according to veterinary advice.
Pay special attention to groups of pigs where you see:
high or suddenly increased levels of general activity or exploration
tail manipulation or chewing
swinging or tucked tails
low or decreasing numbers of visits to an automatic feeder or reduced feed intake
Information on project activities and publications have been continuously published on the FareWellDock-webpage. To date, 16 scientific articles have been published, and 9 are in preparation. Communication to stakeholders has been active, both through the FareWellDock-webpage, including 97 blog posts, and by interviews in media in different countries, popular articles and presentations at producer seminars. In October 2016 the results were presented widely at the EU level to policy makers and other stakeholders at the ‘Meeting and Webinar on Actions to Prevent Tail biting and Reduce Tail docking of Pigs’, organized by the European Commission Directorate General for Health and Food Safety in Grange, Ireland.
Due to the positive experience of the cooperation a decision was made at the last project meeting in DK in October 2016 that we will continue our cooperation as the FareWellDock-network, also inviting further researchers and stakeholders to join. The first activity of the FWD-network will be to organise a satellite meeting at the Congress of the International Society for Applied Ethology in August 2017 in DK, and to launch an emailing list to make sure FWD-network members and other researchers keep updated on research progress and related topics.
The FareWellDock factsheets are out. Below you find the cover factsheet as well as the factsheets on tail docking, enrichment, health and the prediction of tail biting. This post shows images of the English versions, and links to the pdf version of the English factsheets, as well as all factsheets in Danish, Dutch, Finnish, French, Italian, Norwegian and Swedish. Separate pages are available directly showing the factsheets in the other languages (Danish, Dutch, Finnish, French, Italian, Norwegian and Swedish).
