More tail lesions among undocked than tail docked pigs in a conventional herd

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.

The importance of slaughterhouses in monitoring the occurrence of tail biting in pigs - Review

Tail biting in pigs represents a very serious problem in modern pig farming, particularly with the intensification of the industry. It is considered a multifactorial syndrome and can be caused by various factors, leading to significant economic losses through reduced weight gain and partial or total condemnation of slaughtered carcasses due to secondary bacterial infections. The aim of this article is to summarise the current knowledge regarding tail biting in pigs, with a primary focus on the use of slaughterhouses for evaluating tail lesions and monitoring their prevalence. The introduction addresses the factors influencing the incidence of tail biting in pig farms and prevention strategies. Subsequent sections cover topics such as tail docking, the negative effects of pig tail biting, the advantages and drawbacks of examining tail lesions in slaughterhouses, and the methodical procedure for evaluating such lesions. Additionally, the article discusses the relationship between tail lesions and meat inspection findings, as well as the prevalence of tail lesions in various European countries.

Effect of mixing at weaning and nutrient density of the weaner diet on growth performance and welfare of pigs to slaughter

BACKGROUND

Mixing pigs at weaning can compromise pig welfare and growth. Therefore, grouping littermates together may allow a diet nutrient and energy density reduction during the nursery period to reduce feed cost without affecting slaughter weight. This study investigated the combined effect of mixing and reducing dietary energy and nutrient density on growth performance, body lesions (BL), and behaviour in pigs from weaning to slaughter.

RESULTS

Forty-eight litters [554 pigs, 11-12 pigs/litter; Danish Duroc × (Large White × Landrace)] were included in the trial. At 28 days of age, pigs were weaned and housed in nursery rooms in litter groups (INTACT, n = 24) or mixed with other litters and grouped by weight to reduce within-pen pig weight variation (MIXED, n = 24). A dietary regimen meeting pigs' nutritional requirements (CON) and a low-density dietary regimen (LOW; -10% energy and protein) completed a 2 × 2 factorial arrangement (Mixing x Diet, n = 12). On day 74 of age, pigs moved to the grower-finisher accommodation without further mixing and all pigs received the CON dietary regimen. Mixing increased FCR by 4.0% during the nursery period (p = 0.003). Nursery pigs fed LOW experienced a growth retardation which was maintained until slaughter (-2.6 kg slaughter weight; p = 0.025). Initial differences in the coefficient of variation (CV) between MIXED (10.4%) and INTACT (17.6%; p < 0.001) pigs were reduced in CON pens but not in LOW pens (interaction p = 0.025) at the end of the nursery period. MIXED pigs had more fights and BL (p < 0.001) at weaning and showed more aggression (p = 0.003) after being moved to the grower-finisher rooms. At the end of the nursery period, MIXED pigs fed LOW showed the highest number of aggressive behaviours around the feeder (interaction; p = 0.003) and pigs fed LOW showed more damaging behaviour (p < 0.001).

CONCLUSIONS

Mixing animals at weaning had limited impact on growth performance but impaired welfare which was aggravated by energy and nutrient reduction in the nursery diet. Decreasing dietary nutrient density in the nursery stage retarded growth, which could not be compensated for during the growing-finishing period.

Automatic monitoring and detection of tail-biting behavior in groups of pigs using video-based deep learning methods

Automated monitoring of pigs for timely detection of changes in behavior and the onset of tail biting might enable farmers to take immediate management actions, and thus decrease health and welfare issues on-farm. Our goal was to develop computer vision-based methods to detect tail biting in pigs using a convolutional neural network (CNN) to extract spatial information, combined with secondary networks accounting for temporal information. Two secondary frameworks were utilized, being a long short-term memory (LSTM) network applied to sequences of image features (CNN-LSTM), and a CNN applied to image representations of sequences (CNN-CNN). To achieve our goal, this study aimed to answer the following questions: (a) Can the methods detect tail biting from video recordings of entire pens? (b) Can we utilize principal component analyses (PCA) to reduce the dimensionality of the feature vector and only use relevant principal components (PC)? (c) Is there potential to increase performance in optimizing the threshold for class separation of the predicted probabilities of the outcome? (d) What is the performance of the methods with respect to each other? The study utilized one-hour video recordings of 10 pens with pigs prior to weaning, containing a total of 208 tail-biting events of varying lengths. The pre-trained VGG-16 was used to extract spatial features from the data, which were subsequently pre-processed and divided into train/test sets before input to the LSTM/CNN. The performance of the methods regarding data pre-processing and model building was systematically compared using cross-validation. Final models were run with optimal settings and evaluated on an independent test-set. The proposed methods detected tail biting with a major-mean accuracy (MMA) of 71.3 and 64.7% for the CNN-LSTM and the CNN-CNN network, respectively. Applying PCA and using a limited number of PCs significantly increased the performance of both methods, while optimizing the threshold for class separation did result in a consistent but not significant increase of the performance. Both methods can detect tail biting from video data, but the CNN-LSTM was superior in generalizing when evaluated on new data, i.e., data not used for training the models, compared to the CNN-CNN method.

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.

The Relationship between Carcass Condemnations and Tail Lesion in Swine Considering Different Production Systems and Tail Lengths

Simple Summary

Tail biting is considered a major welfare problem in swine production, associated with relevant financial costs for farmers. The European Union has reaffirmed the prohibition of tail docking practices, with all Member States establishing standards for the protection of pigs as well as measures to reduce the need for tail docking and tail biting prevalence. This research aims to assess the importance of tail lesions (using two different scores) and its influence on carcass condemnations considering different production systems and tail length. According to the results, higher tail lesion scores reflected higher total condemnations rates. An intimate association was encountered between the scarring score and total and local carcass condemnations. Tail length was also significant, with undocked animals presenting higher tail lesions scores. Organic batches reported more total condemnations. This research highlights the importance of tail lesions on carcass condemnations that may also be influenced by docking and type of production. These results suggest that scarred tail tissue should be included in the current tail surveillance program.

Abstract

Tail biting has been recognised as an intractable problem in pig production. This study aims to evaluate tail lesion occurrence in slaughtered pigs and explore the relationship between carcass condemnations and tail lesion considering different production systems and tail lengths and to evaluate the importance of creating a detailed tail score classification that includes scarred lesions. Data on a total of 9189 pigs from 73 batches with different tail lengths (undocked; docked mid-length; fully docked) and from distinct production systems (conventional; conventional antibiotic-free and organic) were collected at a Spanish abattoir. Batches with higher tail lesion scores presented a significantly higher chance of total condemnation and total condemnation due to pyaemia, being even more associated with scarring score. The within-batches probability for local condemnations and local condemnation due to abscesses increased significantly with higher scarring scores. Regarding tail length, docked at mid-length and undocked carcasses presented significantly higher odds to be condemned due to abscess. Organic farms showed a higher probability of total condemnations. This research highlights the importance of tail lesions on carcass condemnations that may also be influenced by docking and type of production. Results suggest that scarring score should be included in the tail surveillance program.

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.

Evaluation of Tail Lesions of Finishing Pigs at the Slaughterhouse: Associations With Herd-Level Observations

The prevalence of tail lesions evaluated at the slaughterhouse varies considerably between herds. These lesions result mainly from tail biting, a harmful behavior with multifactorial origin. This study sought to investigate if a batchwise inspection of tails at slaughterhouse could be a useful method to estimate the animal welfare situation in finishing pig herds, and if so, what type and detail of tail scoring such an inspection should utilize. We investigated the distribution of different types of tail lesions and how well their scoring at slaughterhouse was associated with the situation recorded on-farm by a veterinarian as part of routine herd health visits. We also wanted to determine if animal welfare-related herd-level parameters, recorded by herd veterinarians during herd health visits, are associated with tail scoring at the slaughterhouse. A total of 10,517 pigtails from 84 herds were scored for this study. Herd data were collected from the national health classification register for pig farms in Finland and also included annual herd production quality data collected by the slaughterhouse. The scores of the tails varied considerably between the herds. On average, 48.1% (sd = 19.3) of the tails with an average length of 30.4 cm (sd = 2.7) were fully intact, 37.3% (13.9) had healed (length = 26.4, sd = 5.1 cm), 12.4% (9.0) (length = 28.9, sd = 4.3 cm) had minor acute wounds, and 2.3% (2.1) (length = 24.2, sd = 6.0 cm) had major acute wounds. Proportions of different tail lesions at slaughterhouse were associated with or tended to be associated with the following herd-level parameters in regression models: use of wood as enrichment (p < 0.1), one health parameter (leg problems other than arthritis, p < 0.05), and long-term animal welfare estimate (annual mortality, p < 0.05). Detailed tail evaluation at the slaughterhouse shows potential in estimating the tail lesions and long-term welfare level on the farm. By recording only one type of tail condition (such as tails with major acute lesions) at the slaughterhouse, it is not possible to estimate the total tail lesion situation in the herds before slaughter. A more detailed scoring similar to the one used in this trial is recommended.

Tail-Biting in Pigs: A Scoping Review

Tail-biting is globally recognized as a welfare concern for commercial swine production. Substantial research has been undertaken to identify risk factors and intervention methods to decrease and understand this vice. Tail-biting appears to be multifactorial and has proven difficult to predict and control. The primary objective of the scoping review was to identify and chart all available literature on the risk factors and interventions associated with tail-biting in pigs. A secondary objective was to identify gaps in the literature and identify the relevance for a systematic review. An online literature search of four databases, encompassing English, peer-reviewed and grey literature published from 1 January 1970 to 31 May 2019, was conducted. Relevance screening and charting of included articles were performed by two independent reviewers. A total of 465 citations were returned from the search strategy. Full-text screening was conducted on 118 articles, with 18 being excluded in the final stage. Interventions, possible risk factors, as well as successful and unsuccessful outcomes were important components of the scoping review. The risk factors and interventions pertaining to tail-biting were inconsistent, demonstrating the difficulty of inducing tail-biting in an experimental environment and the need for standardizing terms related to the behavior.

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.

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.

The effects of boar on susceptibility to swine inflammation and necrosis syndrome in piglets

Inflammation and necrosis can appear in pigs in several parts of the body simultaneously. The signs can affect newborns, suckling piglets and older pigs, and recent studies suggest that the syndrome is primarily endogenous. Inflammation and necrosis indicate impaired animal welfare, and thus should be controlled in pig production. This can be achieved by improving husbandry conditions. However, the variation in signs also appears to have a genetic component. The aim of the present study was therefore to test the effects of different boars from the Duroc and Pietrain breeds on the prevalence of swine inflammation and necrosis syndrome in their offspring. For this purpose, 646 suckling pigs from 39 sows (two herds) and 19 boars were made available. On the third day of life, the piglets were examined for clinical signs of inflammation and necrosis at tail base, tail tip, ears, face, teats, navel and claws. For the evaluation, we included the boar within the breed and the breed as fixed effects and the sow within the herd as random effects. More than 70% of the piglets were affected at the tail base, ears, coronary bands and heels. Bristle loss, swelling, redness, venous congestion and claw wall bleeding occurred most frequently. Exudation and necrosis affected fewer piglets. None of the piglets was completely free from signs of SINS. Offspring from Duroc boars had significantly lower SINS scores (4.87 ± 0.44) than offspring from Pietrain boars (10.13 ± 0.12). Within the Pietrain breed, significant effects of the boar were observed on inflammation and necrosis levels. Under the present study conditions, using Duroc boars instead of Pietrain boars resulted in a 59% reduction in the SINS scores of their offspring. The SINS score in the offspring of the most favourable Pietrain boar was almost 40% lower than that of offspring in the least favourable. These findings confirm considerable genetic effects on the outcome of SINS under a given husbandry. Further studies are necessary to characterise the genetic effects in detail and to make them useful to combat the syndrome.

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

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.

An in-depth diagnostic exploration of an inflammation and necrosis syndrome in a population of newborn piglets

Inflammation and loss of tail integrity can be reasons for serious impairment of animal welfare and one of the major challenges facing modern pig farming. Evidence from practice increasingly suggests that tail lesions might be caused not only by tail biting but also by inflammation and necrosis, which can occur without any action from other pigs. Such changes are not limited to the tail but can also be observed in the ears, heels and soles, claw coronary bands, teats, navel, vulva and face. To describe inflammatory and necrotic manifestations in newborn piglets, all 146 piglets from 11 sows were clinically examined not later than 2 h after birth. In addition, the tail base of 30 randomly selected piglets out of the 146 was histo-pathologically examined as one of the most conspicuously affected body parts. Over 80% of the newborns showed affections in the tail base, claw wall and heels. In 65-87% of the animals, the coronary bands, teats, the face and the ears were affected. None of the 146 piglets was completely free from pathological manifestations. On average, the piglets were affected in six out of nine body parts simultaneously. Histological examinations showed that clear alterations in the skin were already manifested around the time of birth in all examined piglets. Alterations were characterised by the occurrence of numerous lymphocytes and granulocytes throughout the entire subepithelial connective tissue, predominantly in perivascular and perifollicular localisation but also within directly subepithelial glandular ducts and diffusely within the subepithelial connective tissue. In the majority of individuals, the epithelial structure was intact. This concurrence of symptoms in the newborns indicates a primarily endogenous aetiology of an inflammation and necrosis syndrome. Further studies in diverse herd contexts are necessary to establish the conditions for the emergence of such a syndrome and develop welfare indicators.

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.

Intact Tails as a Welfare Indicator in Finishing Pigs? Scoring of Tail Lesions and Defining Intact Tails in Undocked Pigs at the Abattoir

Tail biting lesions are a potential measure of on-farm animal welfare, as a large range of stressors increase the risk for tail biting outbreaks. Further, tail biting is a major challenge, as lesions due to tail biting decrease animal welfare and health, as well as production efficiency and carcass quality. The aim of this study was to suggest a tail scoring system for use at slaughterhouses processing undocked pigs, and to link tail lesion scores to meat inspection data. A further aim was to suggest a definition for an intact enough tail. To validate the suggested scoring system we assessed tails before and after scalding and compared results to pathological examinations. In total, 14,433 tails were scored, and 117 tails were collected for pathological examination. After scalding, 49.2% of all tails were scored as fully intact. Of tails with lesions 2.5% were scored as having major acute wounds (>2 cm), while 11.6% had minor acute wounds (<2 cm), and 36.7% healed lesions. Intact tails were on average 31.5 cm (SD 2.5 cm) long. Lesion scored at the slaughter-line agreed well with the pathological assessment. Tail lesions were associated with several meat inspection findings: tails with more severe lesions and of shorter length increased the risk for meat inspection findings to a higher degree. A detailed lesion scoring method helps to identify carcasses at risk for condemnations, as well as being a potential method for on-farm welfare estimation. We suggest that a system for scoring tail lesions in undocked pigs should utilize a combination of scoring of the lesion and measuring the tail length. As bite marks or bruises on an otherwise intact tail were not a concern for meat hygiene, we suggest the definition of an intact enough tail could allow the inclusion of tails with these mild changes. Meat inspection findings in carcasses with tails scored as healed, but with no fresh lesions, and with more than 75% of the average intact length remaining were rather similar to those of fully intact tails. Based on these findings we suggest that a tail of this length, and with no visible fresh lesions could also be considered intact enough.

A longitudinal study of pre- and post-weaning tail damage in non-docked pigs

Tail-biting occurs pre-weaning, but literature on tail damage during lactation and on the development of damage over time is sparse, especially for non-docked piglets. We assessed the prevalence of tail damage in non-docked piglets in a commercial Danish piggery during the lactation and weaning period, and investigated the within-animal association of tail lesions pre- and post-weaning. Non-docked piglets (n = 741) from 51 loose-housed sows were individually marked and tracked from birth to 9 weeks (w9) of age. Tail damage was scored during lactation at w1 and w4, and once a week post-weaning (average weaning age 30 days) at w6 to w9. The within-animal association of tail damage before and after weaning was investigated at pig level using generalized mixed models. Tail damage was prevalent already pre-weaning. During the lactation period, the prevalence of tail lesions was 5% at w1 and 42% at w4, with the most prevalent score being 'superficial damages' (66.7%, score 1; pre-weaning scheme: 0 = no damage, 3 = tail wound). Post-weaning, 45% of pigs had a tail lesion at least once over the four assessments, with 16.7% of pigs having a tail lesion at least at two assessments. The majority of lesions were 'minor scratches' (34.2%, score 1; post-weaning scheme: 0 = no damage, 4 = wound - necrotic tail end) and a 'scabbed wound' (19.9%, score 3). The number of pigs with lesions as well as wound severity increased over time. More pigs had a tail wound at w8 (15%, P < 0.001 and < 0.01) and w9 (19%, P < 0.001 and < 0.001) compared to w6 (2.7%) and w7 (5.6%). Pigs with tail lesions pre-weaning (w1: OR 3.0, 95% CI 0.9 to 10.2; w4: OR 3.4, 95% CI 2.0 to 5.8) had a significantly higher risk of having a wound post-weaning, and pigs with lesions at w4 additionally were at a higher risk (OR 3.0, 95% CI 1.8 to 5.1) of having a lesion over several assessments. Females compared to castrated males had a significantly lower risk of having tail lesions at w1 (OR 0.3, 95% CI 0.1 to 0.8). Similarly, females were at a significantly lower risk (OR 0.5, 95% CI 0.4 to 0.9) of having a wound post-weaning, and tended to have a lower risk of having lesions over several assessments (OR 0.7, 95% CI 0.5 to 1.2). Our study confirmed that tail damage is prevalent already during the lactation period, and that pre-weaning tail damage is predictive of tail wounds post-weaning.

Irish pig farmer's perceptions and experiences of tail and ear biting

Abnormal behaviours such as ear and tail biting of pigs is of significant welfare and economic concern. Currently, pig welfare legislation is under renewed focus by the EU commission and is likely to be enforced more thoroughly. The legislation prohibits routine tail docking and requires adequate enrichment to be provided. In Ireland, tail-docking is still the most utilised control mechanism to combat tail biting, but biting is still widespread even in tail-docked pigs. In addition, as pig farms are almost all fully slatted, bedding type material cannot be provided. Thus, the opinions, and practices of farmers in countries like Ireland, which may need to make significant adaptations to typical pig management systems soon, need to be considered and addressed. We carried out a survey of pig farmers during 2015 in order to gain a greater understanding of the extent of biting on Irish farms, perception on the most important preventive measures, current enrichment use and actions following outbreaks. Fifty-eight farmers from 21 Counties responded with an average herd size of 710 ± 597 sows (range 90–3000 sows). Only two farms had experienced no biting in the last year. Of the farms that had experienced tail biting (88%), 86% had also experienced ear biting. The most common concerns relating to biting were condemnation and reduced productivity of bitten pigs with both receiving an average score of 4 (most serious). Ear biting occurred most commonly in the 2nd stage (approximately 47–81 days from weaning) weaner and tail biting in the finishing stage. The most important preventive measures were felt to be taking care of animal health, restricting density, maintaining an even quality of feed/content and maintaining good air movement. Sixty-five percent of respondents added additional enrichment following an outbreak. Chains were the most common form of enrichment currently used (83%). Those not using chains favoured wood, toys and rope (17%). Identification of the most effective and accessible control and prevention measures both for the animals and for the farming community is thus essential. Improved understanding of the concerns and practices of producers, which this survey contributes to, is a first step towards this aim.

Producer Perceptions of the Prevention of Tail Biting on UK Farms: Association to Bedding Use and Tail Removal Proportion

Simple Summary

Tail biting is a serious behavioural problem in modern pig production which causes both animal welfare challenges and economic losses. The aim of this study was to collect information on the perceptions of farmers on how to best prevent tail biting, and on their attitudes towards tail biting and docking. Further, the aim was to investigate if perceptions are influenced by the specific system of farming, with a focus on different levels of bedding use and different tail docking practices. To achieve the goal, pig producers in the UK were surveyed. The results show that producers rank the importance of preventive measures differently to scientists and other experts. This calls for consideration when communicating with producers, and for further consideration of producer knowledge, which might be based on a more holistic view than that of researchers. The study also shows that the perception of how to best prevent and intervene to avoid tail biting differs between farms of different types, and that these perceptions might be influenced by the farmers’ own experiences, which again, might differ between countries and farming systems.

Abstract

Tail biting causes widespread problems both for animal welfare and in the form of economic losses in pig production. This study was performed to better understand the perceptions of farmers on how to best prevent tail biting, and if perceptions are influenced by the specific system of farming, with a focus on different levels of bedding use and docking different proportions of the tail of their pigs. Pig producers in the UK were surveyed on their perceptions of the efficacy of preventive measures and attitudes towards tail biting and docking. In total, 204 responses were included. The results show that producers rank the importance of preventive measures differently to scientists and other experts. This calls for consideration when communicating with producers; and for better integration of knowledge based on practical experiences with scientific results. The study also shows that the perception of how to best avoid tail biting differs between farms of different types, and that these perceptions might be influenced by the farmers´ own experiences—one example being that farms currently using plentiful amounts of bedding also value this more highly as a way to avoid tail biting than those that do not.

The Importance of the Social Sciences in Reducing Tail Biting Prevalence in Pigs

Simple Summary

Tail lesions are a major welfare concern within pig farming. Tail lesions result from biting and chewing of the tail of one pig by another and can indicate boredom and frustration within the herd. While extensive research has been carried out to understand and eliminate tail biting in pigs, findings from scientific studies have often not been applied in practice. This may be due, in part, to a failure to consider the role of farmer behaviour in improving animal welfare. If farmer behaviour does not change, it is unlikely that tail lesion prevalence will change from current levels. In this paper, the shortcomings of traditional behaviour change theories were discussed and a guide for designing human behaviour change interventions for pig farmers was provided. It is essential that collaborations between social scientists and animal welfare scientists occur if research findings are to be put into practice on farms.

Abstract

Tail biting in pigs has been recognised as a welfare problem for several decades, being referred to in scientific literature as far back as the 1940s. Today, animal welfare scientists have a solid understanding of the aetiology of tail biting. Despite this, there has been a major failure in applying research findings on commercial farms. Consequently, tail biting remains a significant problem in modern intensive pig farming. Of all farming industry stakeholders, farmers have the greatest influence over the welfare of their animals. Despite this, little animal welfare research has focused on changing farmer behaviour. Understanding the reasons why farmers act or fail to act to improve animal welfare is key if research findings are to be translated into practical on-farm change. Adopting the principles of behavioural science, this review discussed theory-based methods of identifying barriers to effective tail biting management. A guide was provided for designing behaviour change interventions for farmers using The Behaviour Change Wheel, a systematic framework that links the source of behaviour to suitable interventions. It was concluded that the social sciences are of great importance to ensuring that theory is put into practice.

The Effect of Straw, Rope, and Bite-Rite Treatment in Weaner Pens with a Tail Biting Outbreak

Simple Summary

Young pigs can bite each other’s tails, which is a welfare problem. It begins suddenly and spreads like an “outbreak”. Pig farmers use various methods to prevent tail biting, but if prevention fails, a cure is needed, and there has been little scientific research into how best to stop an outbreak. In a study with 65 groups of young pigs, we tested three methods of stopping tail biting outbreaks which could be practical to use on commercial farms: (1) straw (small amount on the floor), (2) rope, and (3) Bite-Rite (a hanging plastic device with chewable rods). All provided some distraction, but straw stopped an increase in tail injuries more often (75%) than the Bite-Rite (35%), with rope intermediate (65%). Watching the pigs’ behaviour showed that they preferred to interact with rope than the Bite-Rite. We also saw that interacting with other pigs’ tails increased after a week with the Bite-Rite but not with rope or straw. Overall straw worked best, but future studies may find even more effective ways to stop tail biting outbreaks, once they begin.

Abstract

Tail biting in pigs is an injurious behaviour that spreads rapidly in a group. We investigated three different treatments to stop ongoing tail biting outbreaks in 65 pens of 6–30 kg undocked pigs (30 pigs per pen; SD = 2): (1) straw (7 g/pig/day on the floor), (2) rope, and (3) Bite-Rite (a hanging plastic device with chewable rods). Pigs were tail scored three times weekly, until an outbreak occurred (four pigs with a tail wound; day 0) and subsequently once weekly. After an outbreak had occurred, a subsequent escalation in tail damage was defined if four pigs with a fresh tail wound were identified or if a biter had to be removed. Straw prevented an escalation better (75%) than Bite-Rite (35%; p < 0.05), and rope was intermediate (65%). Upon introduction of treatments (day 0), pigs interacted less with tails than before (day −1; p < 0.05). Behavioural observations showed that pigs engaged more with rope than Bite-Rite (p < 0.05). Bite-Rite pigs (but not straw or rope) increased their interaction with tails between day 0 and day 7 (p < 0.05). Straw was the most effective treatment. However, further investigations may identify materials or allocation strategies which are more effective still.

Rearing Undocked Pigs on Fully Slatted Floors Using Multiple Types and Variations of Enrichment

In fully slatted systems, tail biting is difficult to manage when pigs' tails are not docked because loose enrichment material can obstruct slurry systems. This pilot study sought to determine: a) whether intact-tailed pigs can be reared with a manageable level of tail biting by using multiple slat-compatible enrichment; b) whether a variation of enrichment has an effect; and c) whether pigs show a preference in enrichment use. Ninety-six undocked pigs were given the same enrichment items from one week after birth until weaning. At weaning, four different combinations of 8 enrichment items were utilized based on predefined characteristics. These were randomly assigned to 8 pens (n = 12 pigs/pen). Four pens had the same combination (SAME) from assignment and four pens switched combinations every two weeks (SWITCH). Individual lesion scores, interactions with the enrichment, and harmful behaviours were recorded. The average tail score during the experiment was low (0.93 ± 0.02). Only one pig in a SAME pen had a severely bitten tail (partly amputated). The overall level of interaction with enrichment did not decline over time. Pigs interacted with a rack of loose material most frequently (p < 0.001). The study showed promising results for rearing undocked pigs on fully slatted floors using slat-compatible enrichment.

Tail Posture as an Indicator of Tail Biting in Undocked Finishing Pigs

Simple Summary

Tail biting is a large welfare problem in modern pig production, causing pain and reduced health and production. The identification of tail biting is important for minimising the risk of the escalation of the behaviour and its consequences. Tail posture (i.e., tail hanging or curled) has been suggested to depend on the presence of tail wounds and, therefore, has been suggested as an indicator of tail biting. This study investigated the relationship between tail position and tail damages at feeding, since that could be a feasible time for producers to detect tail posture. The experiment showed that 94% of the pigs had curly tails and that pigs with wounds were more likely to have hanging tails than pigs with nondamaged tails. By observing the tail position at feeding, we were able to identify pigs with tail wounds in 68% of cases simply by scoring pigs with hanging tails. To conclude, the scoring of pigs with hanging tails at feeding was found to be a useful tool for identifying tail damages, which may otherwise be difficult to detect by the caretaker.

Abstract

Tail posture (i.e., hanging or curled) has been suggested to be an indicator of tail biting, and hanging tails predisposed to damage. The aim of this study was to investigate if tail posture was feasible as a tail damage indicator in a commercial setting. The study was carried out on one batch of 459 undocked finishing pigs (30–120 kg in weight). Weekly scoring of tail posture was combined with the scoring of tail lesions. Tail posture was observed at feeding to facilitate the usage of the method in commercial settings. A curly tail was observed in 94% of the observations. Pigs with tails scored with “wound” were 4.15 (p < 0.0001) times more likely to have hanging tails, and pigs scored with “inflamed wounds” were 14.24 (p < 0.0001) times more likely to have hanging tails, compared to pigs with nondamaged tails. Tail posture correctly classified tails with “wound” or “inflamed wound” 67.5% of the time, with 55.2% sensitivity and 79.7% specificity, respectively. The method of observing the tail position at feeding seems useful as a complement to normal inspection for detecting tail biting before tail wounds are visible to the caretaker.

Prevalence of an inflammation and necrosis syndrome in suckling piglets

The current study describes the results obtained from clinical examination of over 4700 suckling piglets from 19 individual herds in Germany. In this cohort the prevalence of inflammation and necrosis in the tails, ears, claw coronary bands, heels and teats was determined using a pre-defined scoring system. Results show that already in the 1st days of life, piglets were affected by inflammation and necrosis of the heels (80%), claw coronary bands (50%) and tail base (20%). The praevalences of these alterations in piglets were influenced by genetics (P <0.001) and age, decreasing gradually in the 2nd week of life (P <0.001). Moreover, a correlation between tail length after tail docking and the prevalence of tail necrosis (P⩽0.04) was found. Tail and ear biting as a behavioural trait was not detected during this study. The early onset, appearance and multiple locations of clinical signs of inflammation and the positive correlation with the genetic background of the piglets may suggest an impairment of the innate immune system by infectious and non-infectious agents. This is in contrast to previously described behavioural abnormalities seen in fattening pigs. Considering the obvious reduction of animal welfare due to the described lesions, there is a need to create awareness among pig farmers and to understand the multifactorial causality involved in this inflammation and necrosis syndrome in piglets.

'Phasing out pig tail docking in the EU - present state, challenges and possibilities'

BACKGROUND

European legislation dictates that pig tail docking is not allowed to be performed routinely (European Union. Council Directive 2008/120/EC of 18 December 2008 laying down minimum standards for the protection of pigs. OJ L 47, 18.2.2009). Nevertheless, tail docking is still practiced routinely in many European countries, while four countries stopped routine tail docking completely. Tail docking is also practiced in many countries outside Europe.The Federation of Veterinarians of Europe (FVE), the European Association of Porcine Health Management (EAPHM) together with the European Commission carried out an online survey to investigate the situation regarding the practice of pig tail docking and the provision of enrichment material across 24 European countries. It also focuses on the role of the veterinary profession and gives an overview on published literature regarding the challenges and possibilities related to the raising of pigs with intact tails.

RESULTS

Fifty-seven (57) usable survey responses from 24 countries were received. On average 77% (median = 95%) of pigs are routinely tail-docked. In Finland, Norway, Sweden, Switzerland, less than 5% of the pigs are tail-docked. According to the respondents, 67% of pigs (median = 76%) across the 24 EU countries surveyed are given suitable enrichment materials. Training of veterinary practitioners, their role in advising the producer and undertaking a risk assessment of tail biting were more positively valued in countries that stopped routine tail docking than in countries that had not stopped routine tail docking. Initiatives such as training from national authorities to encourage abandoning tail docking and routine recording of tail biting at the slaughterhouse were identified as two successful items to promote the raising of pigs with entire tails.

CONCLUSION

In many European countries the majority of the pigs are still routinely tail-docked, which is a violation of the European legislation. To stop routine tail docking it is necessary to raise the awareness and education about risk factors to prevent tail biting. The growing knowledge about the reasons for failing voluntary national initiatives as well as about successful measures taken by some countries to make pig production with intact tails feasible should be distributed throughout the EU pig producing community. The veterinary profession has a significant role to play in raising awareness, facilitate knowledge transfer and to identify risk factors and solutions on farm level for the benefit of pig health and welfare.

Automatic early warning of tail biting in pigs: 3D cameras can detect lowered tail posture before an outbreak

Tail biting is a major welfare and economic problem for indoor pig producers worldwide. Low tail posture is an early warning sign which could reduce tail biting unpredictability. Taking a precision livestock farming approach, we used Time-of-flight 3D cameras, processing data with machine vision algorithms, to automate the measurement of pig tail posture. Validation of the 3D algorithm found an accuracy of 73.9% at detecting low vs. not low tails (Sensitivity 88.4%, Specificity 66.8%). Twenty-three groups of 29 pigs per group were reared with intact (not docked) tails under typical commercial conditions over 8 batches. 15 groups had tail biting outbreaks, following which enrichment was added to pens and biters and/or victims were removed and treated. 3D data from outbreak groups showed the proportion of low tail detections increased pre-outbreak and declined post-outbreak. Pre-outbreak, the increase in low tails occurred at an increasing rate over time, and the proportion of low tails was higher one week pre-outbreak (-1) than 2 weeks pre-outbreak (-2). Within each batch, an outbreak and a non-outbreak control group were identified. Outbreak groups had more 3D low tail detections in weeks -1, +1 and +2 than their matched controls. Comparing 3D tail posture and tail injury scoring data, a greater proportion of low tails was associated with more injured pigs. Low tails might indicate more than just tail biting as tail posture varied between groups and over time and the proportion of low tails increased when pigs were moved to a new pen. Our findings demonstrate the potential for a 3D machine vision system to automate tail posture detection and provide early warning of tail biting on farm.

The effect of docking length on the risk of tail biting, tail-directed behaviour, aggression and activity level of growing pigs kept under commercial conditions

Tail biting in domestic pigs relates to a range of risk factors, primarily in the pigs' environment. Preventive tail docking is widely used, and various experimental approaches suggest that docking reduces the risk of tail biting. However, whether the docking length affects the prevalence of tail biting outbreaks is less studied, as is how a shortened tail will affect pigs' social behaviour. The aim of this study was to investigate how three different tail docking lengths, measured at docking, as well as retained intact tails (Short: 2.9 cm; Medium: 5.7 cm; Long: 7.5 cm; and Undocked) affected tail biting risk and behaviour directed at other finisher pigs with the same docking length treatment. Tail lesions were scored weekly, as was behaviour at pen level after introduction to finisher pens and until a potential outbreak of tail biting or slaughter. Pigs from four commercial herds (258 litters) entered the study. Before the pigs entered the finisher section and data collection started, some pigs were excluded, mainly due to tail biting outbreaks in the weaner section. The risk of a tail biting outbreak differed significantly between treatments (P=0.001), with a lowered risk of a tail biting outbreak in Short pens compared with Undocked (P<0.001) and Medium (P<0.05), and was affected by herd as well (P<0.001). Pens in the Long and Undocked treatments were pooled for the behavioural analysis due to low representation, especially in the Undocked treatment. The probability of tail contacts, where a pig interacted with a pen mate's tail, differed between docking length treatments and was highest in the Long/Undocked compared with the Short treatment (P<0.01), but docking length did not affect aggressive behaviour. Docking length affected the risk of a tail biting outbreak and the frequency of tail-directed behaviour in our participating herds, of which three reported a high prevalence of tail biting problems. Only the shortest docking length treatment (Short) reduced the tail biting risk, but did not completely prevent tail biting outbreaks.

Which is the most preventive measure against tail damage in finisher pigs: tail docking, straw provision or lowered stocking density?

One challenge of intensive pig production is tail damage caused by tail biting, and farmers often decrease the prevalence of tail damage through tail docking. However, tail docking is not an optimal preventive measure against tail damage and thus, it would be preferable to replace it. The aim of the current study was to investigate the relative effect of three possible preventive measures against tail damage. The study included 112 pens with 1624 finisher pigs divided between four batches. Pens were randomly assigned to one level of each of three treatments: (1) tail-docked (n=60 pens) v. undocked (n=52 pens), (2) 150 g of straw provided per pig per day on the solid floor (n=56 pens) v. no straw provided (n=56 pens), (3) stocking density of 1.21 m2/pig (11 pig/pen; n=56 pens) v. 0.73 m2/pig (18 pigs/pen; n=56 pens). Tail damage was recorded three times per week throughout the finisher period by scoring the tail of each individual pig. A pen was recorded as a tail damage pen and no longer included in the study if at least one pig in a pen had a bleeding tail wound; thus, only the first incidence of tail damage on pen level was recorded. Data were analysed by a Cox regression for survival analysis assuming proportional hazards. Results are presented as hazards, and a higher hazard means that a pen has a higher risk of tail damage and of it happening earlier in the finisher period. Pens with undocked pigs had a 4.32-fold higher hazard of tail damage compared with pens with docked pigs (P<0.001). Pens with no straw provided had a 2.22-fold higher hazard of tail damage compared with pens with straw provided (P<0.01). No interactions was seen between the treatments, but the effect of tail docking was higher than the effect of straw provision (P<0.001). Stocking density did not have a significant effect on the hazard of tail damage (hazard rate ratios (HRR)=1.67; P=0.064). However, a combination of straw provision and lowered stocking density showed a similar hazard of tail damage as seen with only tail docking (HRR=1.58; P=0.39). In conclusion, tail docking and straw provision were preventive measures against tail damage, and tail docking reduced the risk more than straw provision. A combination of other preventive measures is necessary to reduce the risk of tail damage in undocked pigs to the same level as in docked pigs.

Associations between Antibacterial Treatment and the Prevalence of Tail-Biting-Related Sequelae in Danish Finishers at Slaughter

Secondary infections as a result of tail biting cause substantial economic losses in pig production and are a subject of concern for animal welfare. The use of first-choice antibacterial agents in the treatment of tail biting in finishing pigs is hypothesized to be negatively correlated with the development of systemic infection. This would be expected to reduce the prevalence of post-mortem pyemic sequelae (such as osteomyelitis and abscesses) in finishers with tail-bite lesions. We performed a register-based study that included three Danish databases, holding information on the purchase of antibacterials at herd level (VetStat), herd demographics (Central Husbandry Register), and relevant observations at slaughter (meat inspection data). We included all finishers from indoor production finisher herds that met the inclusion criterion of at least one slaughtered finisher with a recorded tail-bite observation during 2015 at the single largest Danish abattoir. The final dataset held 1,070 herds with one or more tail-bite observations, from which 14,411 of 2,906,626 finishers (0.50%) had an individual record of a tail bite. Within this group of finishers with tail-bite observations, the recorded tail-biting-related sequelae included osteomyelitis (8.1%), abscesses in the hindquarters (10.5%), abscesses in the forequarters (2.3%), abscesses in the mid-section of the carcass (2.9%), abscesses in the limbs (2.4%), and chronic arthritis (0.5%). Due to a high-herd prevalence (>25%), osteomyelitis and abscesses in the hindquarters were selected for further analysis. The occurrence of osteomyelitis and hindquarter abscesses in individual finishers with tail-bite observations was described using a generalized linear mixed effects model with binomial response and logit link. Herd was included as a random effect, while herd size and various antibacterial treatments were tested for inclusion in the model as fixed effects. The final models indicated a significant association between herd size and both osteomyelitis (p = 0.014) and hindquarter abscesses (p < 0.001), with larger herds (2,001–12,000 registered finisher pigs) showing a reduced risk. Further, a negative association was found between the occurrence of hindquarter abscesses and the use of oral pleuromutilin (p = 0.022). The significant association with herd size highlights the potential importance of management factors in reducing the occurrence of tail-bite lesions in finishing pigs.