Injurious tail biting in pigs: how can it be controlled in existing systems without tail docking?

Detecting tail biters by monitoring pig screams in weaning pigs

Early identification of tail biting and intervention are necessary to reduce tail lesions and their impact on animal health and welfare. Removal of biters has become an effective intervention strategy, but finding them can be difficult and time-consuming. The aim of this study was to investigate whether tail biting and, in particular, individual biters could be identified by detecting pig screams in audio recordings. The study included 288 undocked weaner pigs housed in six pens in two batches. Once a tail biter (n = 7) was identified by visual inspection in the stable and removed by the farm staff, the previous days of video and audio recordings were analyzed for pig screams (sudden increase in loudness with frequencies above 1 kHz) and tail biting events until no biting before the removal was observed anymore. In total, 2893 screams were detected in four pens where tail biting occurred. Of these screams, 52.9% were caused by tail biting in the observed pen, 25.6% originated from other pens, 8.8% were not assignable, and 12.7% occurred due to other reasons. In case of a tail biting event, screams were assigned individually to biter and victim pigs. Based on the audio analysis, biters were identified between one and nine days prior to their removal from the pen after visual inspection. Screams were detected earlier than the increase in hanging tails and could therefore be favored as an early warning indicator. Analyzing animal vocalization has potential for monitoring and early detection of tail biting events. In combination with individual marks and automatic analysis algorithms, biters could be identified and tail biting efficiently reduced. In this way, biters can be removed earlier to increase animal health and welfare.

Impact of feed, light and access to manipulable material on tail biting in pigs with intact tails

BACKGROUND

Tail biting (TB) is a welfare issue with economic consequences due to infections and ill-thrift. This study aimed to reduce tail injuries in a high-performing non-tail-docking pig herd.

RESULTS

During eleven years preceding the trial, the annual incidence of tail injuries registered at slaughter in pigs from the herd increased from 3% (equivalent to the national mean) to 10%. It was positively correlated to a high weight gain and negatively correlated to daylight length. The overall incidence of tail injuries during the four years preceding the trial was 9.2% with significant differences between four identically structured buildings for fatteners (I < II < III < IV). The feed was enriched with amino acids, minerals and fibres. The buildings used different illumination strategies, I: standard fluorescent tubes with an invisible flickering light of 30-40% for 14 h daily, II: non-flickering led light for 14 h daily, III (control) and IV: standard fluorescent tubes for 2 h daily. IV had free access to manipulable material (hay-silage), while I-III was offered 100-200 g daily. During the adaptation period (6 months), the incidence of tail injuries decreased significantly in all buildings to a mean of 5.4%. The largest decrease (from 11.4 to 4.3%) was obtained in IV. During the trial period (12 months), the mean incidence of tail injuries decreased in all groups to a mean of 3.0%. There were no differences in treatment incidences of individual pigs due to TB between groups, but the use of enriched pellets due to TB in pens was lowest in II. The low incidence of tail injuries was retained during the post-trial period (6 months) when all buildings used artificial illumination for two hours per day.

CONCLUSIONS

The incidence of TB in fast growing non-tail-docked pigs in the herd was successfully reduced by supplementing the feed with amino acids, minerals, vitamins and fibres. Additional manipulable material accelerated that process and non-flickering illumination may have had an impact in preventing TB. The results obtained do not support the need for tail-docking of pigs, provided that the needs of the pigs in terms of feed ingredients, stocking density and access to manipulable materials are fulfilled.

Comparison between two scoring methods to assess tail damage of docked pig carcasses during postmortem inspection in Ireland

Background

Tail inspection in the abattoir is a tool to help determine the welfare status of pigs. However, methodologies vary widely. Moreover, meat inspection is moving from palpation and incision towards visual-only (VIS) examination. This study investigated whether a VIS examination was sufficient to detect tail damage compared to handling (HAND), which ensures examination of all aspects of the tail.

Method

The severity of tail skin damage (0 [undamaged] - 4 [partial/full loss of tail]) and presence/absence of bruises was scored using both methods after scalding/dehairing of 5498 pig carcasses.

Results

There was a good relationship between methods when evaluating tail skin damage (sensitivity, 82.48%; specificity, 99.98%; accuracy, 98.98%; correlation ρ = 0.84). The results were similar for the presence of bruises (sensitivity, 74.98%; specificity, 99.09%; accuracy, 89.94%; correlation ρ = 0.79). However, the percentage of tails classified as undamaged was higher using VIS (69.9%) than HAND (63.55%) examination. Conversely, VIS detected fewer mild lesions (score 1 - 13.64%; score 2 - 11.73%) than HAND (score 1 - 15.21%; score 2 - 15.53%). A higher percentage of bruises was detected using HAND than VIS (37.96% vs. 29.03%).

Conclusions

Visual evaluation is a valid alternative to handling evaluation of carcass tail damage and bruising.

Are biters sick? Health status of tail biters in comparison to control pigs

BACKGROUND

Tail biting is a multifactorial problem. As the health status is one of the factors commonly linked to tail biting, this study focuses on the health of identified biters. 30 (obsessive) biters are compared to 30 control animals by clinical and pathological examination as well as blood and cerebrospinal fluid samples. In that way, altogether 174 variables are compared between the groups. Moreover, connections between the variables are analysed.

RESULTS

In the clinical examination, 6 biters, but only 2 controls (P = 0.019) were noticeably agitated in the evaluation of general behaviour, while 8 controls were noticeably calmer (2 biters, P = 0.02). Biters had a lower body weight (P = 0.0007) and 13 biters had overlong bristles (4 controls, P = 0.008). In the pathological examination, 5 biters, but none of the controls had a hyperceratosis or inflammation of the pars proventricularis of the stomach (P = 0.018). However, 7 controls and only 3 biters were affected by gut inflammation (P = 0.03). In the blood sample, protein and albumin levels were below normal range for biters (protein: 51.6 g/l, albumin: 25.4 g/l), but not for controls (protein: 53.7 g/l, albumin: 27.4 g/l), (protein: P = 0.05, albumin: P = 0.02). Moreover, 14 biters, but only 8 controls had poikilocytosis (P = 0.05). Although not statistically different between groups, many animals (36/60) were affected by hypoproteinemia and hyponatremia as well as by hypokalemia (53/60) and almost all animals (58/60) had hypomagnesemia. For hypomagnesemia, significant connections with variables linked to tail damage and ear necrosis were detected (r_s/V/ρ ≥ 0.4, P ≤ 0.05).

CONCLUSION

The results suggest that behavioural tests might be helpful in identifying biters. Moreover, cornification and inflammation of the pars proventricularis is linked to becoming a biter. Furthermore, the results highlight the need for appropriate and adjusted nutrient and mineral supply, especially with regard to magnesium.

Old breeds, new solutions? Effects of two different traditional sire breeds on skin lesions, tail lesions, tail losses, performance and behaviour of rearing pigs

Some studies indicated a relationship between modern, fast-growing, lean-meat-producing hybrid pigs and the occurrence of tail-biting, one of the major issues of conventional pig husbandry. Therefore, this study investigated the effects of different local, traditional sire breeds on the behaviour and performance of rearing pigs. Between December 2019 and November 2020, a total of 1 561 piglets were weaned from hybrid sows (Bundes Hybrid Zucht Programm (BHZP) Landrace × BHZP Large White) that were paired with either Swabian-Hall (SH), Bentheim Black Pied (BB) or BHZP-Piétrain (Pi) boars. Tails of the piglets were left intact (43.5%) or docked (56.5%), and male piglets were castrated. Piglets were conventionally reared on fully slatted plastic flooring in mixed-sex groups. Starting one day after weaning, skin lesions were scored once per pig, and tail lesions and losses were scored weekly until the end of rearing. The average daily gain was documented for the suckling and rearing period. The activity behaviour of eight focal pens was analysed using video recordings. Differences between modern and traditional breeds were found in this study for so-called aggressive and non-aggressive biting pronounced by skin and tail lesions and tail losses. Significantly fewer BB pigs had severe skin lesions on the front body than SH or Pi pigs (P < 0.05). Additionally, piglets that were classified as light (<5.6 kg) at weaning showed skin lesion scores of 0 more often than piglets that were classified with a medium (≥5.6-≤8.3 kg) or heavy (>8.3 kg) weaning weight (P < 0.05). In the first half of the rearing period, significantly more BB pigs were assessed as having no tail lesions and tail losses than SH and Pi pigs (P < 0.01). However, these differences disappeared in the second half of rearing. Either docked or undocked Pi pigs had significantly higher average daily gains than SH and BB pigs (P < 0.05). The activity of the focal pens was not influenced by the sire breed or tail lesion class, which might be due to the limited sample size of eight pens. To conclude, the use of the traditional sire breed BB has the potential to reduce injurious behaviour in the offspring. However, adjustments to the housing and feeding should be taken to further reduce the incidence of tail lesions and losses and to enhance performance.

Greek Pig Farmers' Perceptions and Experiences of Tail Biting and Tail Docking

Tail biting is both an important economic and a welfare problem. The primary preventive measure, almost on a routine basis throughout Europe, remains tail docking following a risk analysis. This study aimed to get insight on the perceptions of Greek pig farmers towards tail docking, intervention measures, and risk factors of tail biting, as well as opinions on pig welfare themes. Eighty-two farmers answered a questionnaire provided online and in printed form. In the case of a tail-biting outbreak, the most important intervention measure is the removal of the bitten pig (victim), while feed quality, air movements, and stocking density were ranked as the highest risk factors (p ≤ 0.05). Chains are the most common type of enrichment by 67% followed by plastic objects by 29.5%. Almost half of the farmers reported having no tail-biting problem on their farm, while 64.4% of the respondents have already tried at least once to raise pigs with intact tails. To reduce routine tail docking, it is essential to apply specific farm-oriented solutions effectively. To succeed in this aim, it is important to consider farmers' concerns and practices. This study is the first step in that direction.

Identifying Early Indicators of Tail Biting in Pigs by Variable Selection Using Partial Least Squares Regression

This study examined relevant variables for predicting the prevalence of pigs with a tail lesion in rearing (REA) and fattening (FAT). Tail lesions were recorded at two scoring days a week in six pens in both REA (10 batches, 840 scoring days) and FAT (5 batches, 624 scoring days). To select the variables that best explain the variation within the prevalence of pigs with a tail lesion, partial least squares regression models were used with the variable importance in projection (VIP) and regression coefficients (β) as selection criteria. In REA, five factors were extracted explaining 60.6% of the dependent variable's variance, whereas in FAT five extracted factors explained 62.4% of the dependent variable's variance. According to VIP and β, seven variables were selected in REA and six in FAT with the tail posture being the most important variable. In addition, skin lesions, treatment index in the suckling phase, water consumption (mean), activity time (mean; CV) and exhaust air rate (CV) were selected in REA. In FAT, additional musculoskeletal system issues, activity time (mean; CV) and exhaust air rate (mean; CV) were selected according to VIP and β. The selected variables indicate which variables should be collected in the stable to e.g., predict tail biting.

Individual behavioral correlates of tail biting in pre-finishing piglets

Introduction

Tail biting is a widespread problem in pig production systems and has a negative impact on both animal welfare and farm income. This explorative study aims to validate how tail biting is related to general behaviors at the individual level and explore whether these behaviors are related to a particular type of tail biting: two-stage, sudden-forceful, obsessive, or epidemic.

Methods

This research was conducted in a standard commercial setting where 89 tail-docked pre-finishing piglets divided into 8 groups were observed 4 days per week from 5 to 8 weeks of age. Each piglet was observed for a total of 160 min using continuous focal sampling. Ten individual behaviors were recorded based on the general behaviors expected to be linked to giving tail biting (PCA1), receiving tail biting (PCA2), and tail biting damage (PCA3). These PCAs were assembled and related to tail biting given, tail biting received, and tail biting lesions.

Results

Tail biting did not lead to major damage on the piglets' tail at 8 weeks of age but was observed 420 times, where most of the individuals (72%) were categorized as "biters and victims." When relating PCA1 with tail biting given, piglets that gave more tail biting showed more "active exploration." When relating PCA2 with tail biting received, piglets receiving more tail biting were more "explored while active" and "attacked and explored." When relating PCA2 with tail biting lesions, piglets presenting lesions showed more "agonism." Surprisingly, tail biting lesions were not significantly related to PCA3. The relationship between explorative behaviors and tail biting indicates that the pre-damage stage of two-stage tail biting was the predominant tail biting type, while the damaging stage was likely incipient. The relationship between tail biting and aggression, as well as the minor tail lesions observed suggest that sudden-forceful tail biting was probably present even though it was rarely seen. Obsessive and epidemic tail biting were not observed.

Discussion

This study demonstrates that studying tail biting at the individual level helps to identify the type of tail biting present. This gives directions to farmers for applying appropriate measures to prevent the development of tail biting behavior in piglets.

Welfare of pigs on farm

This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.

VTag: a Semi-Supervised Pipeline for Tracking Pig Activity with a Single Top-View Camera

Precision livestock farming has become an important research focus with the rising demand of meat production in the swine industry. Currently, the farming practice is widely conducted by the technology of computer vision (CV), which automates monitoring pig activity solely based on video recordings. Automation is fulfilled by deriving imagery features that can guide CV systems to recognize animals' body contours, positions, and behavioral categories. Nevertheless, the performance of the CV systems is sensitive to the quality of imagery features. When the CV system is deployed in a variable environment, its performance may decrease as the features are not generalized enough under different illumination conditions. Moreover, most CV systems are established by supervised learning, in which intensive effort in labeling ground truths for the training process is required. Hence, a semi-supervised pipeline, VTag, is developed in this study. The pipeline focuses on long-term tracking of pig activity without requesting any pre-labeled video but a few human supervisions to build a CV system. The pipeline can be rapidly deployed as only one top-view RGB camera is needed for the tracking task. Additionally, the pipeline was released as a software tool with a friendly graphical interface available to general users. Among the presented datasets, the average tracking error was 17.99 centimeters. Besides, with the prediction results, the pig moving distance per unit time can be estimated for activity studies. Lastly, as the motion is monitored, a heat map showing spatial hot spots visited by the pigs can be useful guidance for farming management. The presented pipeline saves massive laborious work in preparing training dataset. The rapid deployment of the tracking system paves the way for pig behavior monitoring.

Do Hens Use Enrichments Provided in Free-Range Systems?

Hens in free-range systems are given enrichments to increase foraging and limit injurious pecking, but the efficacy of enrichment types requires investigation. We studied hen behaviour and feather cover in eight commercial free-range flocks each given access to four enrichments within the shed. Sheds were split into quarters, in which two enrichments (jute ropes (R) + other) were installed. Other enrichments were: lucerne hay bales (B), pecking blocks (PB), pelleted feed (PF), or further R (control). Hens were observed at three ages, at three times per age (−1, 0, ≥1 h relative to PF application), in 1 m diameter circle locations around ropes (ControlR), Enrich (B, PB, PF, R), and Away from each enrichment. Feather scores were recorded at all ages/times, at the Away location only. Significantly more birds were in Enrich locations where PB, B, and PF were available, and least near R, ControlR, and Away locations (p < 0.001). Proportions of birds interacting with enrichments were significantly higher for PB, B, and PF than R (p < 0.001), but enrichments did not generally affect proportions of birds foraging in the litter, apart from a significant decrease (p < 0.001) in PF birds foraging in the Enrich location because they were directing behaviour at PF instead. Feather scores worsened with age (p < 0.001) but were not consistently affected by enrichment. Enrichment replacement rates varied between farms. Enrichments costs were highest for PB and cheapest for R. Enrichments except R were used by hens, but with no obvious effect on feather cover. A balance has to be struck between enrichment benefits to hens and economics, but evidence suggested that hens did not benefit from R.

Tail posture and motion in relation to natural behaviour in juvenile and adult pigs

The tail of pigs has been suggested as a welfare indicator as it can provide insight into a pig's behavioural and emotional states. Tail posture and motion have so far mainly been studied in the context of tail biting behaviour. The aim of this study was to investigate the relationship between pigs' natural behaviour and their tail posture and tail motion. This was studied in a free-range farm in which tail biting is absent. In total 214 pigs of different age categories were observed individually (sows, gilts, boars, and 6-month old pigs) or by group (6-month and 1-year old pigs) for their tail posture, tail motion and behaviour, using live observations and videos obtained by drone. Results showed that a fully curled tail occurred most during locomotion (P < 0.001); and an actively hanging tail occurred more during foraging (P < 0.001), excavation (P = 0.006), feeding (P = 0.017), receipt of agonistic behaviour (P = 0.036), and non-agonistic social interactions (P = 0.046). A fully curled tail (P < 0.001) and a half curled tail (P < 0.005) occurred least in the group of sows. Tail motion was infrequent (6.7% of observations), and involved mainly loosely wagging, which occurred more during locomotion (P = 0.006) and non-agonistic social interactions (P = 0.006). A higher temperature-humidity index increased the probability of half curled tails (P < 0.001) and loose wagging (P < 0.001), while reducing the probability of active (P < 0.001) and passive hanging tails (P = 0.013). These results provide insight into tail posture and tail motion in pigs under semi-natural conditions, showing especially that hanging tails are not primarily associated with tail biting, and that the use of tail postures for welfare assessment should be in consideration with the context in which the animals are kept.

Reduced Stocking Density and Provision of Straw in a Rack Improve Pig Welfare on Commercial Fattening Farms

The aim of this study was to investigate the impact of reduced stocking density in combination with provision of additional enrichment material on pig welfare on-farm. On three growing-finishing farms in Austria, in total 974, 413, and 70 pigs were kept at 1 m²/pig and straw or hay in a rack as additional enrichment material (improved pens, IP; n = 6–38 pens per farm) or in pens complying with the minimum legal requirements of 0.7 m²/pig (control pens, CP; n = 6–37 pens per farm). Behavior as well as skin, tail and ear lesions and pig soiling were assessed at the beginning and in the middle of the fattening period, while performance data were recorded at the end of the fattening period. Data analysis was performed for each farm separately using generalized linear and linear mixed models or Mann-Whitney U-Test. Pigs in IP less frequently manipulated pen mates' ears (Farm 1: Ptreatment*assessment = 0.002; Farm 2: P = 0.002) and body (Farm 1: P = 0.021; Farm 2: P = 0.015) than in CP. Prevalence of skin, tail and ear lesions and soiled pigs did not differ between treatments. In only one farm, average daily weight gain was higher in IP than in CP (Farm 1: P = 0.003). Our findings indicate that increased space allowance and provision of substrate can improve aspects of animal welfare within existing pig fattening systems, without requiring irreversible constructional modifications to the system.

How Housing Conditions Determine the Welfare of Pigs

Humans who care for pigs prefer an environment that not only allows the pigs to express their natural behaviors but also limits the development of aggression and stereotypes. Most of the behavioral and health problems encountered by pigs in barren, conventional conditions are solved by alternative housing systems. However, it is not known whether these systems are advantageous in terms of the performance of pigs. In this work, we review the effects of housing systems on pigs' behaviors and performance, which are among the major indicators of the welfare of these animals. Research results point out that outdoor systems are more ideal for sows and fatteners than buildings. Nonetheless, outdoor housing is associated with two major effects in both groups: increased activity due to environmental exploration and higher space allowance, and increased incidence of injuries compared to indoor systems. Sows are more active when housed in groups, but they experience an increased frequency of injuries. According to the literature, group-housed sows give birth to healthy piglets with good daily weight gains. The difference in the fattening and slaughter performance of pigs raised indoors vs. outdoors remains unclear, and the results reported so far are inconsistent. Outdoor systems seem to be associated with a higher incidence of osteochondrosis and lesions of elbow and hock joints, whereas indoor systems cause a greater degree of body soiling in pigs. Based on the reviewed literature, it may be concluded that outdoor housing helps to solve behavioral issues in pigs but leads to other problems in pig production.

Analysis of Housing Risk Factors for the Welfare of Lean and Heavy Pigs in a Sample of European Fattening Farms

Simple Summary

Animal welfare is a major challenge that most European pig producers have been facing in recent decades to comply with EU legislation and to meet the increasing societal and market demand for pork produced in a sustainable way. Pig welfare is ruled in terms of minimum requirements for housing and management, but stakeholders have considered that both farm-level and animal-based indicators are fundamental to monitor animal welfare. Some of the welfare issues still affecting fattening pigs are the lack of space, bedding and manipulable material, and the continued practice of routine tail docking of pigs. Tail docking is applied routinely across most European countries to reduce the occurrence of severe tail biting lesions, despite its ban in the EU. An observational study on 51 pig farms in seven EU countries, aimed at investigating housing risk factors for the welfare of finishing pigs, showed that body weight and presence of bedded solid floored resting area (BED) identify three clusters of farms. The outcomes of this study confirmed that BED and larger availability of space per pig, above the minimum requirement of EU legislation, can limit the occurrence of lesions in pigs with undocked tails.

Abstract

Pig welfare is affected by housing conditions, the minimum requirements of which are set up by EU legislation. Animal and non-animal-based measures are useful indicators to investigate housing risk factors for pig welfare. An observational study on 51 pig farms in seven EU countries, aimed at investigating housing risk factors for the welfare of finishing pigs, showed body weight and presence of bedded solid floored resting area (BED) identifying three clusters of farms. Farms with BED were featured by no or limited tail docking, larger availability of manipulable materials and lower number of pigs per farm and per annual work unit. In these farms, less skin and ear lesions were found, compared with lean pigs of farms without BED, which were characterized by lower pig space allowance, mortality rate and medication cost. In farms without BED, heavy pigs were featured by more space per pig, more pigs per drinker and higher mortality rate and medication cost per pig, compared to lean pigs. No statistical difference in tail lesions was found between the three farm clusters, although tail docking was performed in all farms without BED and not performed on most farms with BED.

Changes in tail posture detected by a 3D machine vision system are associated with injury from damaging behaviours and ill health on commercial pig farms

To establish whether pig tail posture is affected by injuries and ill health, a machine vision system using 3D cameras to measure tail angle was used. Camera data from 1692 pigs in 41 production batches of 42.4 (±16.6) days in length over 17 months at seven diverse grower/finisher commercial pig farms, was validated by visiting farms every 14(±10) days to score injury and ill health. Linear modelling of tail posture found considerable farm and batch effects. The percentage of tails held low (0°) or mid (1-45°) decreased over time from 54.9% and 23.8% respectively by -0.16 and -0.05%/day, while tails high (45-90°) increased from 21.5% by 0.20%/day. Although 22% of scored pigs had scratched tails, severe tail biting was rare; only 6% had tail wounds and 5% partial tail loss. Adding tail injury to models showed associations with tail posture: overall tail injury, worsening tail injury, and tail loss were associated with more pigs detected with low tail posture and fewer with high tails. Minor tail injuries and tail swelling were also associated with altered tail posture. Unexpectedly, other health and injury scores had a larger effect on tail posture- more low tails were observed when a greater proportion of pigs in a pen were scored with lameness or lesions caused by social aggression. Ear injuries were linked with reduced high tails. These findings are consistent with the idea that low tail posture could be a general indicator of poor welfare. However, effects of flank biting and ocular discharge on tail posture were not consistent with this. Our results show for the first time that perturbations in the normal time trends of tail posture are associated with tail biting and other signs of adverse health/welfare at diverse commercial farms, forming the basis for a decision support system.

Interactive Rooting Towers and Behavioural Observations as Strategies to Reduce Tail Biting on Conventional Pig Fattening Farms

Eight pens (25 pigs/pen; n = 200) provided with an interactive straw-filled rooting tower (experimental group) and five pens (25 pigs/pen; n = 125) with a stationary (fixed) tower without straw (control group) were compared within three fattening periods on a conventional farm with fully slatted flooring. The effectiveness of the tower to trigger favourable behaviour in feeding and outside feeding periods was assessed. The incidence of deep tail injuries was lower in the experimental group (experimental group: Odds Ratio 0.3, p < 0.001) and was influenced by the batch (Odds Ratio: 2.38, p < 0.001) but not by pen and sex. In spring, most pens were excluded due to severe tail biting. Tail injury scores were more severe in the control group in weeks 5, 6 and 7 compared to the experimental group (p = 0.002, p < 0.001, p < 0.001, respectively). Tower manipulation was more frequent during feeding compared to outside feeding time (p = 0.002). More head than tail manipulation occurred in the experimental group (p = 0.03). The interactive tower as the only measure was not appropriate to reduce tail biting sufficiently in pigs with intact tails on a conventional fattening farm. Of high priority to prevent tail biting outbreaks was the early detection of biting pigs.

Cost-Effectiveness Analysis of Seven Measures to Reduce Tail Biting Lesions in Fattening Pigs

Tail biting is an important animal welfare issue in the pig sector. Studies have identified various risk factors which can lead to biting incidents and proposed mitigation measures. This study focused on the following seven key measures which have been identified to affect the risk of tail biting lesions: improvements in straw provision, housing ventilation, genetics, stocking density, herd health, provision of point-source enrichment objects, and adoption of early warning systems. The aim of this study was to examine whether these selected measures to reduce the risk of tail biting lesions in pig fattening are cost-effective. The problem was analyzed by first summarizing the most prospective interventions, their costs and expected impacts on the prevalence of tail biting lesions, second, by using a stochastic bio-economic model to simulate the financial return per pig space unit and per pig at different levels of prevalence of tail biting lesions, and third by looking at how large a reduction in tail biting lesions would be needed at different levels of initial prevalence of lesions to cover the costs of interventions. Tail biting lesions of a severity which would require an action (medication, hospitalization of the pig or other care, or taking preventive measures) by the pig producer were considered in the model. The results provide guidance on the expected benefits and costs of the studied interventions. According to the results, if the average prevalence of tail biting lesions is at a level of 10%, the costs of this damaging behavior can be as high as €2.3 per slaughtered pig (~1.6% of carcass value). Measures which were considered the least expensive to apply, such as provision of point-source enrichment objects, or provided wider production benefits, such as improvements in ventilation and herd health, became profitable at a lower level of efficacy than measures which were considered the most expensive to apply (e.g., straw provision, increased space allowance, automated early warning systems). Measures which were considered most efficient in reducing the risk of tail biting lesions, such as straw provision, can be cost-effective in preventing tail biting, especially when the risk of tail biting is high. At lower risk levels, the provision of point-source objects and other less costly but relatively effective measures can play an important role. However, selection of measures appropriate to the individual farm problem is essential. For instance, if poor health or barren pens are causing the elevated risk of tail biting lesions, then improving health management or enriching the pens may resolve the tail biting problem cost-effectively.

Review: The tale of the Finnish pig tail - how to manage non-docked pigs?

Tail biting is a serious behavioural problem in modern pig production, causing impaired animal welfare and economic losses. In most countries, the detrimental effects of tail biting are counteracted by docking pigs tails. Finland is one of the few countries where tail docking in pigs is totally forbidden. The aim of this paper was to look in detail at features of pig production in Finland in order to try to understand how Finnish producers manage to rear non-docked pigs. The way pigs are housed and managed in Finland is influenced by both European and national legislation, but also by governmental subsidies, industry recommendations and voluntary initiatives. Several features of Finnish pig production might indeed have a preventive role regarding the tail biting risk: these include, among others, a comparably larger space allowance, partly slatted flooring, use of manipulable materials, a good animal health status and meal feeding from long troughs. In addition, Finnish producers are motivated to rear non-docked pigs, which is possibly one of the most important prerequisites for success. The experiences from Finland show that even though tail biting is still a challenge on some farms, in general, it is possible to rear non-docked pigs in intensive production. Potential positive side-effects of enhancing management and housing to facilitate the rearing of non-docked pigs include a good growth rate, a reduced need for antimicrobials and better animal welfare levels.

A Perspective on Strategic Enrichment for Brain Development: Is This the Key to Animal Happiness?

Livestock animals are sentient beings with cognitive and emotional capacities and their brain development, similar to humans and other animal species, is affected by their surrounding environmental conditions. Current intensive production systems, through the restrictions of safely managing large numbers of animals, may not facilitate optimal neurological development which can contribute to negative affective states, abnormal behaviors, and reduce experiences of positive welfare states. Enrichment provision is likely necessary to enable animals to reach toward their neurological potential, optimizing their cognitive capacity and emotional intelligence, improving their ability to cope with stressors as well as experience positive affect. However, greater understanding of the neurological impacts of specific types of enrichment strategies is needed to ensure enrichment programs are effectively improving the individual's welfare. Enrichment programs during animal development that target key neurological pathways that may be most utilized by the individual within specific types of housing or management situations is proposed to result in the greatest positive impacts on animal welfare. Research within livestock animals is needed in this regard to ensure future deployment of enrichment for livestock animals is widespread and effective in enhancing their neurological capacities.

The use of social network analysis to describe the effect of immune activation on group dynamics in pigs

The immune system can influence social motivation with potentially dire consequences for group-housed production animals, such as pigs. The aim of this study was to test the effect of a controlled immune activation in group-housed pigs, through an injection with lipopolysaccharide (LPS) and an intervention with ketoprofen on centrality parameters at the individual level. In addition, we wanted to test the effect of time relative to the injection on general network parameters in order to get a better understanding of changes in social network structures at the group level. 52 female pigs (11-12 weeks) were allocated to four treatments, comprising two injections: ketoprofen-LPS (KL), ketoprofen-saline (KS), saline-LPS (SL) and saline-saline (SS). Social behaviour with a focus on damaging behaviour was observed continuously in 10 × 15 min bouts between 0800 am and 1700 pm 1 day before (baseline) and two subsequent days after injection. Activity was scan-sampled every 5 min for 6 h after the last injection in the pen. Saliva samples were taken for cortisol analysis at baseline and at 4, 24, 48, 72 h after the injections. A controlled immune activation affected centrality parameters for ear manipulation networks at the individual level. Lipopolysaccharide-injected pigs had a lower in-degree centrality, thus, received less interactions, 2 days after the challenge. Treatment effects on tail manipulation and fighting networks were not observed at the individual level. For networks of manipulation of other body parts, in-degree centrality was positively correlated with cortisol response at 4 h and lying behaviour in the first 6 h after the challenge in LPS-injected pigs. Thus, the stronger the pigs reacted to the LPS, the more interactions they received in the subsequent days. The time in relation to injection affected general network parameters for ear manipulation and fighting networks at the group level. For ear manipulation networks, in-degree centralisation was higher on the days following injection, thus, certain individuals in the pen received more interactions than the rest of the group compared to baseline. For fighting networks, betweenness decreased on the first day after injection compared to baseline, indicating that network connectivity increased after the challenge. Networks of tail manipulation and manipulation of other body parts did not change on the days after injection at the group level. Social network analysis is a method that can potentially provide important insights into the effects of sickness on social behaviour in group-housed pigs.

Swine Inflammation and Necrosis Syndrome (SINS)

Tail biting is a prevalent and undesirable behaviour in pigs and a major source of significant reduction in well-being. However, focusing on biting considers only one part of the solution, because tail damage can be found with a high prevalence without any action by other pigs. The lesions are not limited to the tail but can also be found in the ears, heels, soles, claw coronary bands, teats, navel, vulva, and face. Environmental improvement alone often fails to overcome the problem. This review addresses a new inflammation and necrosis syndrome in swine (SINS). It shows the clinical signs and the frequencies of occurrence in different age groups. It compiles scientific evidence from clinical and histopathological studies in newborn piglets that argue for a primary endogenous aetiology of the disease. Bringing together the findings of a broad body of research, the possible mechanisms leading to the disease are identified and then discussed. This part will especially focus on microbe-associated molecular patterns in the circulation and their role in activating defence mechanisms and inflammation. Finally, the methods are identified to ameliorate the problem by optimizing husbandry and selecting a suitable breeding stock.

Is There a Link between Suckling and Manipulation Behavior during Rearing in Pigs?

Simple Summary

Tail biting, a well-known problem in modern pig production, reduces pigs’ welfare and causes economic losses. It is influenced by several external and internal factors, such as housing condition, management, genetics, and age of the animals. Within the internal factors, the individual predisposition to tail biting is difficult to identify. In our study, we analyzed the manipulation behaviors of weaner pigs and their relationship with agonistic behaviors of the piglets during suckling to identify groups of piglets which showed similar suckling and rearing behaviors. In our experiment tail biting increased at the middle and end of rearing. Most animals were observed as both biters and victims of tail biting. During our observations, we found indications that tail-biting pigs showed mainly submissive behavior in teat disputes. These pigs might compensate their submissiveness by biting tails to chase other pigs from resources with restricted access, such as feed or enrichment material. Further research should consider more aspects of a pigs’ personality suitable for early identification of pigs predisposed for later tail biting. This early identification would allow intervention measures to be taken earlier, thereby reducing tail biting and its consequences.

Abstract

Inadequate possibilities to perform oral manipulation behavior for pigs can lead to misdirection and thus tail biting. Our study aimed to analyze manipulation behaviors of weaner pigs with focus on tail biting and the relationship with agonistic characteristics of the piglets during suckling. We analyzed the individual manipulation behavior of 188 weaner pigs. General health condition and tail lesions were determined weekly. Correlations were estimated between weight at weaning and at the end of rearing period, frequency of manipulative rearing behaviors and Dominance and social tension index based on suckling behavior. Principal component and cluster analyses were performed to identify groups of piglets which showed similar suckling and rearing behaviors. Tail biting increased at the middle and end of rearing with switching roles of biters and victims. Tail lesions were correlated with received tail biting behavior but occurred with a delay of more than a week. The frequency of performed tail biting was correlated with dominance index (r_s = −0.256, p < 0.01) and weaning weight (r_s = −0.199, p < 0.05). We assume that performed tail biting is more often observed in pigs who show mainly submissive behavior in teat disputes.

Effect of Straw Provision in Racks on Tail Lesions, Straw Availability, and Pen Hygiene in Finishing Pigs

Unfulfilled exploratory behavior in pigs has been linked to tail biting, which causes reduced performance and welfare. Provision of straw can reduce tail biting, but large straw rations can cause poor hygiene in pens. This study examined whether provision of straw in racks, rather than on the pen floor, can enable larger straw rations without compromising hygiene. The study was conducted on a commercial farm with 458 undocked pigs in 42 pens provided with straw in racks or on the floor. Available straw and manual cleaning requirement were assessed daily, and presence of tail lesions was assessed weekly. Both treatments had a low requirement for manual cleaning (Floor: 1.7%, Rack: 1.8%). Pigs in the rack treatment had a higher incidence of lesions early in the production period, which coincided with these pigs initially not consuming straw from the rack, leading to low straw access. Late in the production period, these pigs had learned how to use the rack and had a lower incidence of lesions than pigs in the floor treatment. Delayed use of the rack may have been linked to undeveloped spatial skills in the pigs, which needs further research.

Abattoir-Based Measures to Assess Swine Welfare: Analysis of the Methods Adopted in European Slaughterhouses

Simple Summary

The welfare of pigs is a major concern among some consumers and pig producers. This concern has driven welfare specialists into the validation of methods and protocols that can be used to evaluate the welfare status of pigs on farms. These protocols require the use of animal-, management and resource-based measures, although data collected from the animals are generally considered more useful. However, due to some limitations, these schemes are not always applicable; therefore, the use of simplified schemes involving the collection of data from pigs at the slaughterhouse has been advocated. Methods and scoring schemes recently described and used in studies performed in European slaughterhouses to determine pig welfare and health are reviewed in the present manuscript. A focus on the scoring schemes for lesions of the body and viscera during post-mortem activities at the abattoir is provided. These methods can be used to benchmark a welfare scheme suitable for all European competent authorities and professionals working in the context of pig welfare.

Abstract

The assessment of swine welfare requires feasible, reliable, and reasonable indicators. On-farm evaluation of pig welfare can provide valuable information to veterinarians and farmers. However, such protocols can result expensive and time-consuming. With this regard, an interest in the appraisal of swine welfare at abattoir has grown over the recent years. In particular, the use of certain lesions collected directly from slaughtered animals to determine the welfare status of pigs has been evaluated by several authors. In the present review, the different methods developed to score lesions collected directly from the body and the viscera of animals slaughtered in European abattoirs (“abattoir-based measures”) are presented. The text specifically focuses on the methods currently available in the literature for the scoring of body, pluck and gastric lesions during post-mortem activities. Moreover, the strengths and weaknesses of abattoir-based measures schemes are discussed. To conclude, the future perspectives of the assessment of pig welfare at the slaughterhouse are described, appealing for a benchmarking system that can be systematically used by veterinarians and other professional figures involved in the process.

Maternal and direct genetic parameters for tail length, tail lesions, and growth traits in pigs

Tail length and tail lesions are the major triggers for tail biting in pigs. Against this background, 2 datasets were analyzed to estimate genetic parameters for tail characteristics and growth traits. Dataset 1 considered measurements for trait tail length (T-LEN) and for the growth traits birth weight (BW), weaning weight (WW), postweaning weight (PWW), and average daily gain (ADG) from 9,348 piglets. Piglets were born in the period from 2015 to 2018 and kept on the university Gießen research station. Dataset 2 included 4,943 binary observations from 1,648 pigs from the birth years 2016 to 2019 for tail lesions (T-LES) as indicators for nail necrosis, tail abnormalities, or tail biting. T-LES were recorded at 30 ± 7 d after entry for rearing (T-Les-1), at 50 ± 7 d after entry for rearing (end of the rearing period, T-LES-2), and 130 ± 20 d after entry for rearing (end of fattening period, T-LES-3). Genetic statistical model evaluation for dataset 1 based on Akaike's information criterion and likelihood ration tests suggested multiple-trait animal models considering covariances between direct and maternal genetic effects. The direct heritability for T-LEN was 0.42 (±0.03), indicating the potential for genetic selection on short tails. The maternal genetic heritability for T-LEN was 0.05 (±0.04), indicating the influence of uterine characteristics on morphological traits. The negative correlation between direct and maternal effects for T-LEN of -0.35 (±0.13), as well as the antagonistic relationships (i.e., positive direct genetic correlations in the range from 0.03 to 0.40) between T-LEN with the growth traits BW, WW, PWW, and ADG, complicate selection strategies and breeding goal definitions. The correlations between direct effects for T-LEN and maternal effects for breeding goal traits, and vice versa, were positive but associated with a quite large SE. The heritability for T-LES when considering the 3 repeated measurements was 0.23 (±0.04) from the linear (repeatability of 0.30) and 0.21 (±0.06; repeatability of 0.29) from the threshold model. The breeding value correlations between T-LES-3 with breeding values from the repeatability models were quite large (0.74 to 0.90), suggesting trait lesion recording at the end of the rearing period. To understand all genetic mechanisms in detail, ongoing studies are focusing on association analyses between T-LEN and T-LES, and the identification of tail biting from an actor's perspective.

Prospects for the Analysis and Reduction of Damaging Behaviour in Group-Housed Livestock, With Application to Pig Breeding

Innovations in the breeding and management of pigs are needed to improve the performance and welfare of animals raised in social groups, and in particular to minimise biting and damage to group mates. Depending on the context, social interactions between pigs can be frequent or infrequent, aggressive, or non-aggressive. Injuries or emotional distress may follow. The behaviours leading to damage to conspecifics include progeny savaging, tail, ear or vulva biting, and excessive aggression. In combination with changes in husbandry practices designed to improve living conditions, refined methods of genetic selection may be a solution reducing these behaviours. Knowledge gaps relating to lack of data and limits in statistical analyses have been identified. The originality of this paper lies in its proposal of several statistical methods for common use in analysing and predicting unwanted behaviours, and for genetic use in the breeding context. We focus on models of interaction reflecting the identity and behaviour of group mates which can be applied directly to damaging traits, social network analysis to define new and more integrative traits, and capture-recapture analysis to replace missing data by estimating the probability of behaviours. We provide the rationale for each method and suggest they should be combined for a more accurate estimation of the variation underlying damaging behaviours.

Association Between Tail-Biting and Intestinal Microbiota Composition in Pigs

Tail-biting (TB) in pigs is a serious behavioral disorder. It is an important challenge in swine production as it impacts animal welfare and health and the economics and safety of the pork meat supply chain. To prevent TB, approaches including enrichment material and tail docking are proposed but none are optimal. Nutrition appears to be an important factor in TB behavior, perhaps by modulating the intestinal microbiota (IM). Our aim was to assess the association between TB behavior and IM in pigs through comparisons of IM in groups of biter, bitten and non-biter/non-bitten pigs. Each group composed of 12 pigs was formed at the beginning of the growing/finishing phase based on a target behavior analysis centered on TB behavior for the biter group and a score of damages caused to the tail for the bitten group. Blood and fecal samples were collected from each pig during a TB episode, at time 0, t0, and when the TB episode was considered finished, 4 weeks later, at time 1, t1. Serum cortisol level was determined by ELISA and used as an indicator of stress. The pig's fecal microbiota was analyzed from DNA extracted from freshly collected fecal matter using amplicon sequencing of the V4 hypervariable region of the 16S rRNA gene. Serum cortisol levels were significantly higher in either the biter or bitten pig groups compared to the negative control group (p = 0.02 and p = 0.01, respectively). The microbiota alpha-diversity was not significantly different between all groups, biter, bitten and negative control. Analyses of beta-diversity, however, revealed a significant difference between either the biter or the bitten group in comparison to the non-biter/non-bitten negative control group in terms of structure and composition of the microbiota. Lactobacillus were significantly more abundant in the negative control group compared to the two other groups (p = 0.001). No significant difference was revealed between the biter and bitten groups. Quantitative real-time PCR (qPCR) confirmed that lactobacilli were more abundant in the negative control group. Our study indicates that TB behavior is associated with the IM composition in pigs.

Swine inflammation and necrosis syndrome is influenced by husbandry and quality of sow in suckling piglets, weaners and fattening pigs

BACKGROUND

Swine inflammation and necrosis syndrome (SINS) is a newly identified syndrome in swine that can affect different parts of the extremities in suckling piglets. This study investigates the hypotheses that the clinical signs of SINS have histological equivalents, that SINS can also be observed in weaners and fatteners, that improving sow quality and husbandry (here the supply of water and fibre) can reduce the signs, and that coprostasis in sows is significantly associated with SINS in their offspring. From a cohort of 123 hybrid sows, the twenty sows exhibiting the best conditions and the twenty exhibiting the worst conditions were selected based on detailed scores from coronary bands, soles, heels, claws and teats. Half of the sows in each group, along with their offspring, were kept under conventional conditions, while the environment for the remaining sows in each group was improved with drinking bowls, water disinfection and additional feeding with hay and straw. In total, 115 suckling piglets, 113 weaners and 103 fatteners were scored for the degree of inflammation and necrosis of their tails, ears, teats, coronary bands, soles, heels and claws.

RESULTS

The clinical signs of SINS are associated with inflammatory signs at the histological level. SINS scores in suckling piglets, weaners and fatteners derived from low-quality sows under standard husbandry conditions were high, but they decreased significantly when husbandry was improved (water consumption and additional fibre). Sow quality had significant effects on suckling piglets and weaners under standard husbandry conditions. Coprostasis in sows led to significantly higher SINS scores in their offspring at any age. Improved husbandry conditions were associated with a reduced prevalence of coprostasis (R2 = 0.74). Taking all factors together, husbandry improvements, sow quality and coprostasis explained 57, 67 and 45% of SINS score variance in suckling piglets, weaners and fatteners, respectively.

CONCLUSION

The present study shows that SINS is not limited to suckling piglets but can also be found in weaners and fatteners. Coprostasis in sows is significantly correlated with SINS in their offspring and adds a good prognostic tool. Water supply and fibre could play a crucial role in combatting the syndrome.

Welfare Aspects of Raising Entire Male Pigs and Immunocastrates

Simple Summary

Surgical castration of male piglets without pain treatment and anaesthesia is not only a welfare problem but also violates the integrity of the animals. The favoured alternatives of raising entire male pigs (EM) with or without immunocastration (vaccination against boar taint) may, however, impose additional welfare problems under the current housing and management conditions. This focused review is intended to summarise the current state of scientific knowledge and practical reports on critical welfare issues and risk factors. Raising EM with or without subsequent immunocastration could be a welfare conform, future-oriented alternative to conventional surgical castration of pigs, provided that they are kept in a healthy and socially stable environment with sufficient physical resources, as safeguarded by measures of enhanced animal care and management control.

Abstract

For a long time, scientists assumed that newborns have a severely limited sense of pain (if any). However, this assumption is wrong and led to a “start of the exit” from piglet surgical castration. Some of the currently discussed or already implemented alternatives such as general or local anaesthesia during surgical castration raise additional welfare concerns as well as legal problems and/or are hardly applicable. The favoured long-term, welfare-friendly “gold standard” is to raise entire male pigs (EM). However, this may also impose certain welfare problems under the current conventional housing and management conditions. The specific types of behaviour displayed by EM such as mounting and aggressive behaviours but also increased exploration, which are partially linked to sexual maturation, increase the risk for injuries. The current status of knowledge (scientific literature and farmer experiences) on housing of EM suggests that environmental enrichment, space, group-stability, social constellation, feeding (diet and feeder space), health and climate control are critical factors to be considered for future housing systems. From an animal welfare point of view, an intermediate variant to be favoured to reduce problematic behaviour could be to slaughter EM before reaching puberty or to immunize boars early on to suppress testicular function. Immunization against endogenous GnRH can reduce EM-specific problems after the 2nd vaccination.

A High Enrichment Replenishment Rate Reduces Damaging Behaviors and Increases Growth Rate in Undocked Pigs Kept in Fully Slatted Pens

One of the difficulties in complying with the prohibition of routine tail docking is a lack of effective alternative solutions to prevent tail biting, especially in fully slatted systems. This study compared three slat-compatible enrichment replenishment strategies for pigs. Forty-eight mixed-sex pens (six males and six females/pen) of undocked pigs were followed from birth to slaughter. Pre-weaning, half the pigs were provided with enrichment materials (a cardboard cup, rubber toy, hessian cloth and bamboo), in addition to a rope for the sows, in all farrowing crates. Post-weaning, all pens were enriched with eight identical items, including an elevated rack supplied with fresh-cut grass, and objects of wooden, bamboo, rubber, and fabric materials presented in various ways. However, three different replenishment frequencies were applied: "Low" (replenished on Monday/Wednesday/Friday), "Medium" (replenished once daily), and "High" (replenished ad libitum). Individual pigs were weighed on days 0, 49, 91, and 113 post-weaning. Direct behavior observations were conducted twice weekly at pen level (10 min/day/pen), and tail and ear lesion scores of individual pigs were also recorded every other week. These measurements were taken during the post-weaning period. The cost of all enrichment materials used was calculated. Pre-weaning enrichment only contributed to a lower ear lesion score (P = 0.04). No difference in lesion scores was found between post-weaning treatments. "Low" replenishment rate pigs performed more damaging behaviors (tail/ear biting, belly-nosing, mounting, other biting, and aggressive behaviors combined) than "High" and "Medium" pigs (P < 0.01). The average daily gain in the finishing stage was higher in "High" than "Low" pigs (P < 0.05). Although sporadic tail biting occurred, only 0.69% of the pigs had their tails bitten severely enough that they became shorter than half of a normal undocked tail. The average enrichment cost for the post-weaning period was <€2 per pig. In conclusion, the high enrichment replenishment rate increased growth and reduced damaging behaviors compared to the low replenishment rate pigs. Overall, these findings show that the provision and regular replenishment of multiple, slat-compatible, enrichment sources can reduce tail damage to manageable levels without the need for tail docking.

Can increased dietary fibre level and a single enrichment device reduce the risk of tail biting in undocked growing-finishing pigs in fully slatted systems?

This study evaluated the effectiveness of combined dietary and enrichment strategies to manage tail biting in pigs with intact tails in a conventional fully-slatted floor housing system. A 2 × 2 × 2 factorial design was used. Pigs had either a high fibre (weaner 5.3% and finisher 11.6% of crude fibre) or standard fibre diet (weaner 3.7% and finisher 5.9% of crude fibre). In the weaner stage, pigs had either a spruce wooden post (supplied in a wall-mounted dispenser) or a rubber floor toy as a enrichment device, and in the finisher stage, they had either the same or alternate enrichment item. Six hundred and seventy-two pigs were assigned to 48 pens of 14 pigs and followed from weaning until slaughter. Individual tail lesion scores and pen level behaviours were directly recorded every 2 weeks. Twenty-six pens had tail biting outbreaks and 161 injured pigs needed removal for treatment. Pigs fed with the high fibre diet performed more tail biting (p < 0.05) and tended to have a worse tail damage scores than those fed the standard fibre diet (p = 0.08). Pigs which had the floor toy as weaners and wood as finishers tended to have fewer tail lesions in the finisher stage than their counterparts (p = 0.06). Pigs receiving the floor toy as enrichment interacted with the enrichment more frequently overall (p < 0.001) and performed fewer harmful behaviours in the weaner stage (p < 0.05). Overall, higher fibre in the diet in a relatively barren environment did not help reduce tail biting or tail lesions. Altering the fibre level in the pigs’ diet and providing a single enrichment device to undocked pigs on fully slatted floors resulted in a high level of tail biting and a large proportion of pigs with partial tail amputation.

Impact of amount of straw on pig and pen hygiene in partly slatted flooring systems

BACKGROUND

Straw is a beneficial enrichment material for pigs, shown to improve welfare through reducing tail biting. Straw has previously been identified as one of the means of how to raise pigs without tail docking, through improving natural exploratory behaviour. Straw has however been linked to poor pen hygiene, making farmers reluctant to use straw and has largely not been implemented in commercial farming worldwide. Straw is a beneficial enrichment material for pigs, shown to improve welfare and reduce abnormal behaviour such as tail biting.

RESULTS

This study investigates the impact of straw on pig and pen hygiene in pens with partly slatted floor in three grower and four finishing pig batches on five commercial farms (2329 pigs, 211 pens) in Sweden which were providing straw daily. Each batch was divided into two treatments; Control: 50-600 g straw/pen/day based on the farm normal straw ration; and Extra straw; (=doubled Control ration). The pens were scored based on cleanliness of the pigs, solid and slatted pen floor every second week. The pig and pen hygiene were mostly scored as clean in both treatments, overall around 1% of the observations were considered dirty/soiled.

CONCLUSIONS

As very few pens or pigs were considered dirty, it was concluded that straw provision is possible without risking poor pig and pen hygiene. Few observations in this study were considered dirty regardless of amount of straw that was provided, and had likely to do with other factors in the production rather than straw ration. These results implies that straw could be used in partly slatted pens in order to improve pig environment but more research is needed to quantify the impact of other external factors related to climate (e.g. temperature, humidity, velocity).

A Proposed Role for Pro-Inflammatory Cytokines in Damaging Behavior in Pigs

Sickness can change our mood for the worse, leaving us sad, lethargic, grumpy and less socially inclined. This mood change is part of a set of behavioral symptoms called sickness behavior and has features in common with core symptoms of depression. Therefore, the physiological changes induced by immune activation, for example following infection, are in the spotlight for explaining mechanisms behind mental health challenges such as depression. While humans may take a day off and isolate themselves until they feel better, farm animals housed in groups have only limited possibilities for social withdrawal. We suggest that immune activation could be a major factor influencing social interactions in pigs, with outbreaks of damaging behavior such as tail biting as a possible result. The hypothesis presented here is that the effects of several known risk factors for tail biting are mediated by pro-inflammatory cytokines, proteins produced by the immune system, and their effect on neurotransmitter systems. We describe the background for and implications of this hypothesis.

Omics Application in Animal Science-A Special Emphasis on Stress Response and Damaging Behaviour in Pigs

Increasing stress resilience of livestock is important for ethical and profitable meat and dairy production. Susceptibility to stress can entail damaging behaviours, a common problem in pig production. Breeding animals with increased stress resilience is difficult for various reasons. First, studies on neuroendocrine and behavioural stress responses in farm animals are scarce, as it is difficult to record adequate phenotypes under field conditions. Second, damaging behaviours and stress susceptibility are complex traits, and their biology is not yet well understood. Dissecting complex traits into biologically better defined, heritable and easily measurable proxy traits and developing biomarkers will facilitate recording these traits in large numbers. High-throughput molecular technologies (“omics”) study the entirety of molecules and their interactions in a single analysis step. They can help to decipher the contributions of different physiological systems and identify candidate molecules that are representative of different physiological pathways. Here, we provide a general overview of different omics approaches and we give examples of how these techniques could be applied to discover biomarkers. We discuss the genetic dissection of the stress response by different omics techniques and we provide examples and outline potential applications of omics tools to understand and prevent outbreaks of damaging behaviours.

Prioritisation of animal welfare issues in the UK using expert consensus

BACKGROUND

The welfare of all animals under human management is an area of consistent public concern, but strategies to improve welfare may vary across species. In this study, expert consensus, using a modified Delphi approach, was used to prioritise welfare issues of farmed and companion animals in the UK.

METHODS

The study involved 117 experts, divided between eight species groups. Experts were recruited from a broad range of disciplines. Two rounds of online surveys were conducted using the online survey tool, and the final round was an in-person workshop with a subsection of experts (n=21). The experts agreed that welfare issues should be ranked considering three categories: (1) severity, (2) duration and (3) perceived prevalence.

RESULTS

A comprehensive list of welfare issues was generated for each species by discussion boards (cats, rabbits and horses) or by literature review (dogs, pigs, poultry, cattle and small ruminants). In the first online survey, the experts scored each welfare issue using the three categories (severity, duration and prevalence) on a 6-point Likert scale, where 1=never/none and 6=always/high. Lists of welfare issues were reduced to 25 per cent-59 per cent of the total number, by determining mean ranks from expert ratings. In round 2, experts were asked whether they agreed or disagreed with the rankings. In the final stage, during the workshop, the top-ranking welfare issues for animals were determined for individual animals (considering the greatest severity and duration, in the expert's opinion) and for perceived prevalence.

CONCLUSIONS

Overall, prioritised welfare issues included lack of knowledge of welfare needs, social behaviour issues, problem behaviours, inappropriate diet and environment, lack of veterinary care, consequences from breeding decisions, poor pain management, delayed euthanasia and chronic ill health. The Delphi process resulted in consensus on the most significant welfare challenges of animals in the UK and can help to guide future research and education priority decisions.

High biosecurity and welfare standards in fattening pig farms are associated with reduced antimicrobial use

In order to reduce antimicrobial use in pig production, the consequences of insufficient biosecurity and welfare problems need to be known. This study aimed to investigate associations between the number of antimicrobial treatments per fattening pig, and biosecurity, indicators for animal welfare as well as the prevalence of lesions at slaughter. The data used in this study were extracted from the pig health and welfare classification system (Sikava), which gathers data on medicine usage, meat inspection, animal welfare and the condition of farm buildings from over 95% of pig production in Finland. The data were registered during years from 2011 to 2013. Upon antimicrobial prescription, information on the number of fattening pigs treated and the main reason for treatment was recorded. In addition, at least 4 times per year, pig farms registered in Sikava were visited by the farm veterinarian who assessed, among other things, biosecurity and indicators for animal welfare (air quality, condition of facilities, cleanliness, enrichment and stocking density). Finally, data from slaughterhouse inspections were collected (number of carcasses with joint infection, abscesses, lung lesions, pleurisy and liver lesions). For analysis, these datasets were aggregated at the farm level to a quarter of a year. During the studied period, the mean number of antimicrobial treatments per fattening pig per 3 months was equal to 0.09. The main reasons for antimicrobial treatments were musculoskeletal diseases, tail biting and respiratory disorders (42, 33 and 12% of diagnoses, respectively). The meat inspection scoring indicated that as much as 14.7% of all pigs had pleurisy, 5.3% liver lesions and 4.1% abscesses. A standard zero-inflated negative binomial model was used to identify factors associated with the number of antimicrobial treatments per pig. The count of antimicrobial treatments per pig increased with the size of a farm. Regardless of prevalence of lesions, farms with poor drinking equipment, insufficient enrichment and a combination of poor condition of pens and high stocking density were associated with an increased number of antimicrobial treatments for musculoskeletal diseases per pig. Problems with stocking density and enrichment were associated with the number of antimicrobial treatments for tail biting, although these results depended on prevalence of joint infections. Problems with air quality and the combination of poor cleanliness and poor condition of facilities were associated with increased number of antimicrobial treatments due to respiratory diseases. This study suggests that by improving biosecurity and welfare at pig farms, antimicrobial use can be reduced.

Review: Early life predisposing factors for biting in pigs

The pig industry faces many animal welfare issues. Among these, biting behaviour has a high incidence. It is indicative of an existing problem in biters and is a source of physical damage and psychological stress for the victims. We categorize this behaviour into aggressive and non-aggressive biting, the latter often being directed towards the tail. This review focusses specifically on predisposing factors in early life, comprising the prenatal and postnatal periods up to weaning, for the expression of aggressive and non-aggressive biting later in life. The influence of personality and coping style has been examined in a few studies. It varies according to these studies and, thus, further evaluation is needed. Regarding the effect of environmental factors, the number of scientific papers is low (less than five papers for most factors). No clear influence of prenatal factors has been identified to date. Aggressive biting is reduced by undernutrition, cross-fostering and socialization before weaning. Non-aggressive biting is increased by undernutrition, social stress due to competition and cross-fostering. These latter three factors are highly dependent on litter size at birth. The use of familiar odours may contribute to reducing biting when pigs are moved from one environment to another by alleviating the level of stress associated with novelty. Even though the current environment in which pigs are expressing biting behaviours is of major importance, the pre-weaning environment should be optimized to reduce the likelihood of this problem.

Utilization of Optical Flow Algorithms to Monitor Development of Tail Biting Outbreaks in Pigs

A study was conducted to evaluate activity changes in pigs associated with the development of tail-biting outbreaks using optical flow algorithms. Pigs (n = 120; initial body weight = 25 ± 2.9 kg) housed in four pens of 30 pigs were studied for 13 weeks. Outbreaks of tail biting were registered through daily observations. Behavior of pigs in each pen was video-recorded. Three one-hour video segments, representing morning, noon, and afternoon on days 10, 7, and 3 before and during the first outbreak of tail biting were scanned at 5-min intervals to estimate time budget for lying, standing, eating, drinking, pig-directed behavior, and tail biting. The same video segments were analyzed for optical flow. Mean optical flow was higher three days before and during the tail-biting outbreak, compared to 10 days before the outbreak (p < 0.05), suggesting that pigs may increase their activity three days before tail-biting outbreaks. All optical flow measures (mean, variance, skewness, and kurtosis) were correlated (all p < 0.01) with time spent standing, indicating that movement during standing may be associated with optical flow measures. These results suggest that optical flow might be a promising tool for automatically monitoring activity changes to predict tail-biting outbreaks in pigs.