Category Archives: Welfare

Did European pig-welfare legislation reduce pig welfare? Perhaps not, but experts confirm that common indestructible materials are not proper enrichment for pigs at all, except perhaps for an enhanced novel branched-chains design.

Enrichment, Legal, Manipulation, Pigs, Policy, Straw, Tail biting, Tail docking, Welfare, , , , , , , ,

Published as:
Marc B.M. Bracke and Paul Koene, 2019. Expert opinion on metal chains and other indestructible objects as proper enrichment for intensively-farmed pigs. PLOS ONE. Available at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212610.

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)

Level 1 (almost sufficient): Branched chains (5.1)

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:

Chains as enrichment for pigs (Book chapter with 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

Original abstract of the PLOS ONE paper:

Marc B.M. Bracke and Paul Koene, 2019. Expert opinion on metal chains and other indestructible objects as proper enrichment for intensively-farmed pigs. PLOS ONE. Available at http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212610.

Abstract

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.


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.
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).

Dealing with tail biting in pigs with intact tails

Enrichment, Pigs, Tail biting, Tail docking, Welfare,

PigProgress – Early indicators for tail biting in pigs Should pigs in the EU keep the end of their tails, or should tails be docked in the 1st days of the pigs’ lives to reduce risk of tail biting? The subject is widely discussed which also underlines that there is no easy answer. However, there is work in progress and so are some very promising results, writes pig welfare expert Vivi Aarestrup Moustsen. Read more in Pig Progress

Providing enrichment materials enhances play in sows around regrouping

Enrichment, Pigs, Welfare, , , ,

Provision Point-Source Materials Stimulates Play in Sows but Does Not Affect Aggression at Regrouping

By Emma Catharine Greenwood, William H. E. J. Van Wettere, Jessica Rayner, Paul E. Hughes and Kate J. Plush, 2019. Animals 2019, 9(1), 8;

Abstract

When sows are mixed into groups, hierarchies form and resulting aggression and stress can affect production and welfare. This study determined the effect of providing point-source materials on aggressive and play behaviors in gestating sows. Large white cross Landrace sows were mixed after insemination; six pens of 12 sows were housed in ‘standard’ pens, and six pens of 12 sows were housed in ‘enhanced’ pens. The ‘enhanced’ pens each contained two rubber mats, eight strands of 24 mm-thick sisal rope and two yellow plastic disks, suspended from the roof. The sows remained in these pens until pregnancy confirmation. Salivary cortisol concentration, injury counts, and sow behaviors were recorded the day before mixing (day 1), mixing (day 0) and post-mixing day 1, day 4, day 7 and day 20. At farrowing, reproductive outcomes were obtained. Play was observed (including locomotor and object play) in the ‘enhanced’ pen, and percentage of time spent playing was greater on d4 (1.48 ± 0.3 Square root transformed data (2.84% non-transformed adjusted mean)), d7 (1.43 ± 0.3 (2.97%)) and d20 (1.64 ± 0.3 (3.84%)), compared to d0 (0.56 ± 0.3 (0.70%)) and d1 (0.87 ± 0.3 (1.67%) (p < 0.05)). No play was observed in standard housing. Aggression, salivary free cortisol concentrations and injuries were unaffected (p > 0.05). The provision of materials had no impact on aggression, although their presence maintained sow interest and play behavior, suggesting a positive effect.

How to control injurious tail biting without tail docking of pigs

Health, Pigs, Tail biting, Tail docking, Welfare,

Injurious tail biting in pigs: How can it be controlled in existing systems without tail docking. By D’Eath RB, Arnott G, Turner SP, Jensen T, Lahrmann HP, Busch ME, Niemi JK, Lawrence AB, Sandøe P, 2014. Animal 8:1479-97.

Abstract Tail biting is a serious animal welfare and economic problem in pig production. Tail docking, which reduces but does not eliminate tail biting, remains widespread. However, in the EU tail docking may not be used routinely, and some ‘alternative’ forms of pig production and certain countries do not allow tail docking at all. Against this background, using a novel approach focusing on research where tail injuries were quantified, we review the measures that can be used to control tail biting in pigs without tail docking. Using this strict criterion, there was good evidence that manipulable substrates and feeder space affect damaging tail biting. Only epidemiological evidence was available for effects of temperature and season, and the effect of stocking density was unclear. Studies suggest that group size has little effect, and the effects of nutrition, disease and breed require further investigation. The review identifies a number of knowledge gaps and promising avenues for future research into prevention and mitigation. We illustrate the diversity of hypotheses concerning how different proposed risk factors might increase tail biting through their effect on each other or on the proposed underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible, manipulable natural materials can be of considerable benefit. Further comparative research is needed into materials, such as ropes, which are compatible with slatted floors. Also, materials which double as fuel for anaerobic digesters could be utilised. As well as optimising housing and management to reduce risk, it is important to detect and treat tail biting as soon as it occurs. Early warning signs before the first bloody tails appear, such as pigs holding their tails tucked under, could in future be automatically detected using precision livestock farming methods enabling earlier reaction and prevention of tail damage. However, there is a lack of scientific studies on how best to respond to outbreaks: the effectiveness of, for example, removing biters and/or bitten pigs, increasing enrichment, or applying substances to tails should be investigated. Finally, some breeding companies are exploring options for reducing the genetic propensity to tail bite. If these various approaches to reduce tail biting are implemented we propose that the need for tail docking will be reduced.

Prenatal stress and enrichment affect piglet behaviour

Brain, Enrichment, Pigs, Welfare

Impact of prenatal stress and environmental enrichment prior to weaning on activity and social behaviour of piglets (Sus scrofa). By Sophie Brajon, Nadine Ringgenberg, Stephanie Torrey, Renée Bergeron, Nicolas Devillers, 2017. Applied Animal Behaviour Science 197: 15-23.

Highlights

• Prenatal stress (PNS) can have detrimental effects on piglets behaviour and welfare.

• Pre-weaning enrichment may compensate negative effects of PNS in piglets.

• PNS effects were delayed after weaning at d 27 as shown by an increased inactivity.

• Enrichment had positive effects but its removal at weaning affected behaviour.

• Pre-weaning enrichment did not compensate for the effects of PNS.

Abstract

Prenatal stress (PNS) can have detrimental effects on behaviour and welfare, such as decreased exploration. Whether housing enrichment before weaning compensate negative effect of PNS in commercial pigs is unknown. To address this question, 44 sows were assigned to either a mixing stress (T) or a control (C) treatment in mid-gestation. During lactation, half of the T and C sows were housed with their 12-piglets litter in straw enriched pens (E) while the others were housed in standard farrowing crates (S). At weaning, 6 piglets per litter were selected and moved to non-enriched standard pens. Lying down, exploration and social behaviour were recorded in the home-pen before weaning (d 6, d 12, d 20), on the day of weaning (d 21), and after weaning (d 22, d 27) using scan and one-zero samplings. Three piglets per litter were individually subjected to a social isolation test and a social confrontation test at d 17. Data were analysed by day using mixed models with PNS, housing enrichment and their interaction as fixed effects. We found no interaction between the treatments, suggesting the absence of a compensatory effect of enrichment on PNS. Pre-weaning enrichment promoted exploration (P< 0.004) and seemed to improve comfort, as piglets spent more time lying down (P< 0.02), but was associated with reduced locomotion and play fighting (P< 0.03) compared to no enrichment. After weaning, E piglets explored less (P< 0.01) and played less (locomotion and fighting play: P< 0.0003) than S piglets. They also performed more belly-nosing at d 27 (P =0.04). These results support the idea that the removal of enrichment at weaning negatively affects piglets. The E piglets exhibited higher emotional reactivity than S piglets (i.e. more high-pitched calls and escape attempts) during the social isolation test, but no clear effect was observed during the confrontation test. The effects of prenatal stress on behaviour were only apparent after weaning. On d 27, T piglets spent more time lying (P =0.02), and showed reduced exploration (P =0.004), locomotion play (P=0.03), fighting play (P=0.04) and mounting behaviour (P =0.002) than C piglets. In conclusion, both prenatal stress and pre-weaning enrichment affected piglet behaviour, but a compensatory effect of enrichment on the negative effects of prenatal stress could not be demonstrated.

Simple enrichment block may improve pig welfare

Enrichment, Manipulation, Pigs, Welfare

Enrichment in the Sucker and Weaner Phase Altered the Performance of Pigs in Three Behavioural Tests. By Cameron Ralph, Michelle Hebart and Greg M. Croninm 2018. Animals 8: 74.

Abstract

We tested the hypothesis that provision of enrichment in the form of enrichment blocks during the sucker and weaner phases would affect the behaviour of pigs. We measured the performance of pigs in an open field/novel object test, a maze test, an executive function test and the cortisol response of the pigs after exposure to an open field test. The provision of enrichment blocks altered the behaviour of the pigs in all three tests and these changes suggest an increased willingness to explore and possibly an increased ability to learn. The behavioural tests highlighted that young pigs have the capacity to learn complex tasks. Our findings support the notion that the benefits of enrichment cannot be evaluated by measuring the interactions the animal has with the enrichments in the home pen and it may simply be beneficial to live in a more complex environment. We have highlighted that the early rearing environment is important and that the management and husbandry at an early age can have long-term implications for pigs. The enrichment we used in this study was very simple, an enrichment block, and we provide evidence suggesting the provision of enrichment effected pig behavioural responses. Even the simplest of enrichments may have benefits for the welfare and development of young pigs and there is merit in developing enrichment devices that are suitable for use in pig production.

Risk factors for tail lesions in weaner pigs

Pigs, Straw, Tail biting, Tail docking, Welfare

Factors influencing the risk for tail lesions in weaner pigs (Sus scrofa). by Angelika Grümpel, Joachim Krieter, Christina Veit, Sabine Dippel, 2018. Livestock science 216: 219-226.

Highlights

We identified five factors influencing the risk for tail lesions in weaner pigs.•

We can recommend regression tree analysis for describing tail lesion risk factors.•

Data interpretation should include information on correlations between variables.

Abstract

Tail biting is a behavioural disorder in pigs which results in tail lesions. Many factors must be considered to reduce the risk for tail biting due to the multifactorial character of this behaviour. We developed a software-based tail biting management tool called “SchwIP” for analysing farm individual risk factors for tail biting in weaner pigs. SchwIP was applied on 25 conventional farms throughout Germany who kept weaner pigs in closed barns (median 1,800 weaning places). The farms were visited up to three times between August 2016 and November 2017 and a total of 368 pens were assessed. Data regarding enrichment, pen environment, feed, water, climate, health, farm management, transport and regrouping were analysed with regression tree analysis (RT) using pen level prevalence of tail lesions (%) as the outcome variable. There were five primary influencing factors for tail lesions: docking status, stocking density, daily weight gain, suckling piglet losses and number of litters mixed during weaning. The correlation between observed and predicted prevalence of tail lesions across all pens was 0.6. Most of the factors may represent combinations of influences on a farm which agree with the multifactorial nature of the problem. Even though weight gain may also be influenced by tail biting behaviour and thus be a parallel outcome, it could be used by farmers as an indicator for initiating closer examination and intervention. The use of RT for visualising complex risk factor analyses is recommendable, though their analytical suitability for clustered data should further be evaluated.


What can carcass-based assessments tell us about the lifetime welfare status of pigs?

Pigs, Welfare, , ,

What can carcass-based assessments tell us about the lifetime welfare status of pigs?
Carroll et al. 2018. Livestock Science

Highlights

• The use of carcass measures to understand lifetime pig welfare status was explored.
• Tail and skin lesions acquired in early life remain visible on the carcass.
• These lesions were not necessarily visible on the live animal in later life.
• Carcass weight was negatively associated with persistent tail injuries.
• Therefore carcass lesions and weight provide useful lifetime welfare information.

Abstract

There is increasing interest in developing abattoir-based measures of farm animal welfare. It is important to understand the extent to which these measures reflect lifetime welfare status. The study aim was to determine whether lesions acquired during different production stages remain visible on the carcass, and the degree to which carcass-based measures may reflect broader health and welfare issues. 532 animals were assessed at 7, 9 and 10 weeks of age (early life, EL), and at 15 and 20 weeks of age (later life, LL) for tail lesions (TL), skin lesions (SL) and a number of health issues (HI) including lameness and coughing. Pigs were categorised according to when individual welfare issues occurred in the production process; ‘early life’ [EL], ‘later life’ [LL], ‘whole life’ [WL], or ‘uninjured’ (U) if showing no signs of a specific welfare issue on-farm. Following slaughter, carcasses were scored for tail length, tail lesions, and skin lesions and cold carcass weights (CCW) were obtained. Generalised linear, ordinal logistic and binary logistic fixed model procedures were carried out to examine the ability of TL, SL and HI lifetime categories to predict carcass traits. Pigs with TL in EL, LL and WL had higher carcass tail lesion scores than U pigs (P < 0.001). Pigs with TL in LL (P < 0.05) and WL (P < 0.001), but not in EL (P > 0.05), also had shorter tails at slaughter than U pigs. In relation to TL scores, U pigs also had a higher cold carcass weight compared to LL and WL (P < 0.001), but not EL pigs (P > 0.05). Pigs with SL in EL, LL and WL had higher healed skin lesion scores on the carcass than U pigs (P < 0.001). Health issues recorded during lifetime were not reflected in carcass measures used (P > 0.05). The current study shows that tail lesions and skin lesions, acquired at least 10 weeks before slaughter, remain evident on the carcass and consequently, may be useful as tools to assist in determining the lifetime welfare status of pigs. Low CCW was associated with tail lesions, supporting previous research suggesting that tail lesions have a negative impact on growth performance in pigs.