Category Archives: Pigs

Pig enrichment affects immune response to disease

Effect of enriched housing on levels of natural (auto-)antibodies in pigs co-infected with porcine reproductive and respiratory syndrome virus (PRRSV) and Actinobacillus pleuropneumoniae.
Lu Luo, Ingrid Daniëlle Ellen van Dixhoorn, Inonge Reimert, Bas Kemp, Jantina Elizabeth Bolhuis and Hendrik Karel Parmentier 2017. Vet Res (2017) 48:75.


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.

Docking piglet tails: How much does it hurt and for how long?

Docking piglet tails: How much does it hurt and for how long?

By Pierpaolo Di Giminiani, Abozar Nasirahmadi, Emma M. Malcolm, Matthew C. Leach, Sandra A. Edwards. 2017. Physiology & Behavior 182: 69-76.


• Short and long-term behavioural changes due to tail docking in pigs are described.
• Vocalisations suggested the procedure to be painful for piglets.
• The behaviour sampling adopted detected no changes up to 2 days post-tail docking.
• Long-term effects of tail injury on mechanical nociceptive thresholds were absent.


Tail docking in pigs has the potential for evoking short- as well as long-term physiological and behavioural changes indicative of pain. Nonetheless, the existing scientific literature has thus far provided somewhat inconsistent data on the intensity and the duration of pain based on varying assessment methodologies and different post-procedural observation times. In this report we describe three response stages (immediate, short- and long-term) through the application of vocalisation, behavioural and nociceptive assessments in order to identify changes indicative of potential pain experienced by the piglets. Furthermore, we evaluated the following procedural differences: (1) cautery vs. non-cautery docking; (2) length of tail removal. Sound parameters showed a significantly greater call energy and intensity exhibited by docked vs. sham-docked piglets (P < 0.05). Observations of general activity of the animals in a test situation failed to detect a difference among treatments (P > 0.05) up to 48 h post-tail docking. Similarly, no difference in mechanical nociceptive thresholds indicative of long term pain was observed at 17 weeks following neonatal tail docking (P > 0.05). The present results highlight the potential for the use of measures of vocalisation to detect peri-procedural changes possibly associated with evoked pain. Nonetheless, activity and nociceptive measures failed to identify post-docking anomalies, suggesting that alternative methodologies need to be implemented to clarify whether tail docking is associated with short- and long-term changes attributable to pain experienced by the piglets.

Gene expression of mechanistic pain in pig spinal cord and dorsal root ganglia

Determination of stable reference genes for RT-qPCR expression data in mechanistic pain studies on pig dorsal root ganglia and spinal cord.

By Sandercock DA, Coe JE, Di Giminiani P, Edwards SA. 2017. Res Vet Sci. 2017 Sep 28;114:493-501.

RNA expression levels for genes of interest must be normalised with appropriate reference or “housekeeping” genes that are stably expressed across samples and treatments. This study determined the most stable reference genes from a panel of 6 porcine candidate genes: beta actin (ACTB), beta-2-microglobulin (B2M), eukaryotic elongation factor 1 gamma-like protein (eEF-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), succinate dehydrogenase complex subunit A (SDHA), Ubiquitin C (UBC) in sacral dorsal root ganglia and spinal cord samples collected from 16 tail docked pigs (2/3rds of tail amputated) 1, 4, 8 and 16weeks after tail injury (4 pigs/time point). Total RNA from pooled samples was measured by SYBRgreen real-time quantitative PCR. Cycle threshold values were analysed using geNorm, BestKeeper and NormFinder PCR analysis software. Average expression stability and pairwise variation values were calculated for each candidate reference gene. GeNorm analysis identified the most stable genes for normalisation of gene expression data to be GAPDH>eEF-1>UBC>B2M>ACTB>SDHA for dorsal root ganglia and ACTB>SDHA>UBC>B2M>GAPDH>eEF-1 for spinal cord samples. Expression stability estimates were verified by BestKeeper and NormFinder analysis. Expression stability varied between genes within and between tissues. Validation of most stably expressed reference genes was performed by normalisation of calcitonin gene related polypeptide beta (CALCB). The results show similar patterns of CALCB expression when the best reference genes selected by all three programs were used. GAPDH, eEF-1 and UBC are suitable reference genes for porcine dorsal root ganglia samples, whereas ACTB, SDHA and UBC are more appropriate for spinal cord samples.

Can enrichment help reduce tail docking?

In several episodes, leading welfare researchers explain the results they obtained within the international framework ‘FareWellDock’. This project investigates how to steer away from tail docking. Swedish and Danish researchers took a look at straw – does its use reduce the occurrence of tail biting?

Read more in Pig Progress.

From the article:
Tail docking is completely banned in Sweden, Finland and Switzerland.

Science suggests that lack of proper manipulable material is one of several major risk factors for tail biting.

A moderate amount of straw (150 g/pig/day) reduced the risk of injurious tail biting by more than two-fold, while docking seemed to be more effective as it reduced the risk by more than four-fold.

A combination of straw and increased space (1.2 m2 per pig) reduced the risk (of first occurrence) in undocked pigs to the same level as found in docked pigs kept under high stocking density (0.72 m2 per pig) without straw.

To provide a suitable outlet for exploratory behaviour under production conditions, materials have to be varied and complex, and are most effective when easily destroyed by chewing, or if they are edible.

Increasing the amount of straw from 10 to up to 400g/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.

Left-over straw may be a promising candidate method to screen for appropriate level of straw allocation.

From beak to tail – Mechanisms underlying damaging behaviour in laying hens and pigs (Satellite workshop ISAE-2017)

August 7, 2017 a very nice one-day meeting was held in Aarhus (DK) to discuss feather pecking in laying hens and tail biting in pigs.  The meeting was a joint initiative of FareWellDock and GroupHouseNet. A Skype4business connection made it possible for about 10 external participants to join the meeting in addition to the 60 delegates present in person.


Opening of the meeting, introduction and networking session,
Anna Valros, Sandra Edwards

9:50-11:00 Theme 1: Mechanisms underlying the link between health and damaging behaviour
Invited speakers: Janicke Nordgreen (pigs), Jerine van der Eijk (poultry)

Mini research seminar
≥ Lisette van der Zande: The estimation of genetic effects of tail damage on weaned pigs and its influence on production traits
≥ Anja Brinch Riber: Link between feather pecking and keel bone damage
≥Mirjam Holinger: Does chronic intermittent stress increase tail and ear manipulation in pigs?
≥Laura Boyle: The effect of removing antibiotics from the diets of weaner pigs on performance of ear and tail biting behaviours and associated lesions

11:00-11:20 Coffee/tea break
11:20-12:20 Theme 1 continues: Group and plenary discussion, Anna Valros
12:20-13:20 Lunch break
13:20-14:30 Theme 2: Predisposing factors for damaging behaviour during early development
Invited speakers: Jo Edgar (poultry) and Armelle Prunier (pigs)

Mini research seminar
≥Ute Knierim: A tool to work on risk factors during rearing for feather pecking in laying hens
≥Elske de Haas, Margrethe Brantsæter & Fernanda Machado Tahamtani: Disrupting availability of floor substrate in the first weeks of life influences feather pecking during rearing and lay – a Dutch and Norwegian approach
≥Anouschka Middelkoop: Effect of early feeding on the behavioural development of piglets around weaning
≥Irene Camerlink: The crooked mind of the commercial pig: can we rectify abnormal biting behaviour by early and later life conditions?

14:30-14:50 Coffee/tea break
14:50-15:50 Theme 2 continues: Group and plenary discussion, Sandra Edwards
15:50 Closing of workshop

Some tweets from the workshop:

Acute lethal aggression is increasingly seen in commercial pig farming, as is excessive neonatal aggression (Irene Camerlink)

About 50 studies link (in-)adequate foraging to injurious feather pecking in poultry (Jo Edgar).

Maternal care strongly influences chick behavioural development (Jo Edgar)

Study: Lots of ear biting on Irish pig farms, up to 50% of pigs; Follow up: Antibiotic use may play a role (both causing & treating) (Laura Boyle).

Feather pecking appears to be linked to keel bone damage (Anja Brinch Riber).

Feather pecking is associated with elevated specific immune response (Jerine van der Eijk).

Tipping bucket model of feather pecking
Tipping bucket model of feather pecking (modified after Bracke et al. 2012 model for tail biting).

Characterization of short- and long-term mechanical sensitisation following tail docking in pigs

Characterization of short- and long-term mechanical sensitisation following surgical tail amputation in pigs. By Pierpaolo Di Giminiani, Sandra A. Edwards, Emma M. Malcolm, Matthew C. Leach, Mette S. Herskin & Dale A. Sandercock. 2017. Nature Scientific Reports.

Commercial pigs are frequently exposed to tail mutilations in the form of preventive husbandry procedures (tail docking) or as a result of abnormal behaviour (tail biting). Although tissue and nerve injuries are well-described causes of pain hypersensitivity in humans and in rodent animal models, there is no information on the changes in local pain sensitivity induced by tail injuries in pigs. To determine the temporal profile of sensitisation, pigs were exposed to surgical tail resections and mechanical nociceptive thresholds (MNT) were measured in the acute (one week post-operatively) and in the long-term (either eight or sixteen weeks post-surgery) phase of recovery. The influence of the degree of amputation on MNTs was also evaluated by comparing three different tail-resection treatments (intact, ‘short tail’, ‘long tail’). A significant reduction in MNTs one week following surgery suggests the occurrence of acute sensitisation. Long-term hypersensitivity was also observed in tail-resected pigs at either two or four months following surgery. Tail amputation in pigs appears to evoke acute and sustained changes in peripheral mechanical sensitivity, which resemble features of neuropathic pain reported in humans and other species and provides new information on implications for the welfare of animals subjected to this type of injury.

See also our article in PigProgreess.

Ear necrosis in pigs

An investigation of ear necrosis in pigs
Jeonghwa Park, Robert M. Friendship, Zvonimir Poljak, Josepha DeLay, Durda Slavic, and Catherine E. Dewey
Can Vet J v.54(5): 491-495.


Porcine ear necrosis was investigated in 23 conveniently chosen farms, consisting of 14 case farms and 9 control farms. Biopsies of lesions and oral swabs from pigs on 11 case farms were examined by histology and bacterial culture. All farms were visited for observations and a survey on management, housing, and the presence of other clinical signs or behavioral vices. Histological examination revealed that the lesions began on the surface and progressed to deeper layers, and that vascular damage did not appear to be the initiating cause. Spirochetes were only rarely observed in histological examination and were not cultured from biopsies and oral swabs. Staphylococcus aureus and Staphylococcus hyicus were cultured from 91% and 66% of samples, respectively. Ear biting and a humid environment were associated with ear necrosis. On some farms large numbers of pigs were affected and lesions were sometimes extensive. The condition appears to be an infectious disease beginning on the surface of the skin; contributing environmental and management factors are likely.

Practical guide to enrichment for pigs

A Practical Guide to Environmental Enrichment for Pigs – A handbook for pig farmers. By AHDB Pork, UK

“This guide aims to give practical advice to pig farmers surrounding the complex
issue of providing suitable environmental enrichment to pigs. It provides
useful information from the knowledge of farmers, researchers and scientific
literature on the different ways environmental enrichment can be provided for
differing types of housing and systems. The information is set out in sections
by housing type, and in each, the types of enrichments that are most suited
to each system are discussed, including their properties, how to present
the enrichment, quantities and practical considerations, such as ease of
installation, maintenance and costs.” (cited from the introduction in the guide).


Reducing crude protein levels in pig diets to increase protein efficiency may also increase damaging behaviours, esp. under conditions of poor sanitation

A link between damaging behaviour in pigs, sanitary conditions, and dietary protein and amino acid supply
By Yvonne van der Meer, Walter J. J. Gerrits, Alfons J. M. Jansman, Bas Kemp, J. Elizabeth Bolhuis. PLOS, Published: May 8, 2017


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.

Mixing weaned piglets did affect tail biting

The effect of mixing piglets after weaning on the occurrence of tail-biting during rearing
By Christina Veit, Kathrin Büttner, Imke Traulsen, Marvin Gertz, Mario Hasler, Onno Burfeind, Elisabeth grosse Beilage, Joachim Krieter, 2017. Livestock Science 201: 70–73.

The aim of this study was to investigate the effects on tail-biting during rearing of housing piglets of the same litter compared to piglets from different litters. The treatments “litter-wise” (LW, n =240) and “mixed litters” (ML, n =238) were housed in five identical units. Each tail was scored regarding tail lesions and tail losses once per week with a four-point score (0= no damage/original length to 3= severe damage/total loss). The effect of week after weaning had highly significant influences on tail lesions (p<0.001). Tail-biting started in the second week after weaning, with an increasing severity during rearing. First tail losses were observed in the fourth week after weaning. The batch and the interaction between treatment and batch had highly significant influences on tail losses at the end of rearing (p<0.001). Depending on batch, piglets in the LW or ML treatment were more affected by tail-biting.