Category Archives: Tail biting

Tail posture as an indicator of tail biting in undocked pigs

Tail posture as an indicator of tail biting in undocked finishing pigs

By Torun Wallgren, Anne Larsen and Stefan Gunnarsson, 2019. Animals. Special Issue Environmental Enrichment of 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.


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.

How to control injurious tail biting without tail docking of pigs

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

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

Tail posture predicts tail biting outbreaks in pigs

Tail posture predicts tail biting outbreaks at pen level in weaner pigs. By Helle Pelant Lahrmann, Christian Fink Hansen, Rick D’Eath, Marie Erika Busch, Björn Forkman, 2018. Applied Animal Behaviour Science 200: 29-35.


• Changes in tail posture can predict a tail biting outbreak at pen level.

• Percentage of hanging tails in pens close to an outbreak was almost doubled.

• A correlation between number of tail damages and lowered tails were identified.

• No changes in activity was identified prior to a tail biting outbreak.


Detecting a tail biting outbreak early is essential to reduce the risk of pigs getting severe tail damage. A few previous studies suggest that tail posture and behavioural differences can predict an upcoming outbreak. The aim of the present study was therefore to investigate if differences in tail posture and behaviour could be detected at pen level between upcoming tail biting pens (T-pens) and control pens (C-pens). The study included 2301 undocked weaner pigs in 74 pens (mean 31.1 pigs/pen; SD 1.5). Tails were scored three times weekly (wound freshness, wound severity and tail length) between 07:00 h–14:00 h from weaning until a tail biting outbreak. An outbreak (day 0) occurred when at least four pigs had a tail damage, regardless of wound freshness. On average 7.6 (SD 4.3) pigs had a damaged tail (scratches + wound) in T-pens on day 0. Tail posture and behaviour (activity, eating, explorative, pen mate and tail directed behaviour) were recorded in T-pens and in matched C-pens using scan sampling every half hour between 0800–1100 h 1700–2000 h on day -3, -2 and -1 prior to the tail biting outbreak in T-pens. Further, to investigate if changes in tail posture could be a measure for use under commercial conditions, tail posture was recorded by direct observation from outside the pen. The live observations were carried out just before tail scoring on each observation day until the outbreak. The video results showed more hanging/tucked tails in T-pens than in C-pens on each recording day (P < 0.001). In T-pens more tails were hanging on day -1 (33.2%) than on day -2 (24.8%) and day -3 (23.1%). Further, the number of tail damaged pigs on day 0 was correlated with tail posture on day -1, with more tails hanging in pens with 6–8 and >8 tail damaged pigs than in pens with 4–5 tail damaged pigs (P < 0.001). Live observations of tail posture in T-pens also showed a higher prevalence of hanging tails on day 0 (30.0%; P < 0.05) than on day -3/-2 (17.2%), -5/-4 (15.4%) and -7/-6 (13.0%). No differences in any of the recorded behaviours were observed between T-pens and C-pens. In conclusion, lowered tails seem to be a promising and practical measure to detect damaging tail biting behaviour on pen level even when using live observations. However, there were no changes in activity, eating, exploration or tail-directed behaviours prior to a tail biting outbreak.

3D cameras can detect lowered tail posture before an outbreak of tail biting in pigs

Automatic early warning of tail biting in pigs: 3D cameras can detect lowered tail posture before an outbreak. By Richard B. D’Eath, Mhairi Jack, Agnieszka Futro, Darren Talbot, Qiming Zhu, David Barclay, Emma M. Baxter. 2018. PlosOne.


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.

Enrichment may be joyful and reduce stress in young pigs

Pre-weaning environmental enrichment increases piglets’ object play behaviour on a large scale commercial pig farm. By Chung-Hsuan Yang, Heng-Lun Ko, Laura C. Salazar, Lourdes Llonch, Xavier Manteca, Irene Camerlink, Pol Llonch, 2018. Applied Animal Behaviour Science 202: 7-12 Environmental enrichment is a legal requirement for European pig farms. The suitability of enrichment materials for neonatal pigs is understudied and has not been tested in commercial settings. This study investigates the effect of hanging objects and substrate as two enrichment strategies pre-weaning, and compares the effect of these enrichment objects on play behaviour, aggression, growth and stress coping ability during lactation until 10 days after weaning. Farrowing crates were equipped with either six hanging objects (OB), a substrate box with wood bark (SUB), or nothing (control; CON). The behaviour of over 600 piglets (∼210 piglets/treatment) was recorded weekly by instantaneous scan sampling (10 s/piglet, repeated 6 times per day for 6 days). Aggression was monitored through skin lesions on focal piglets on 1 day before weaning and 1 and 2 days after weaning. Piglets were weighed individually every week. Stress coping ability was assessed through salivary cortisol from a sample of six piglets per litter on 1 day before (baseline), and on days 1 and 2 after weaning. Both enrichment groups showed more object play during lactation as compared to the control group (P < 0.001). The amount of object play increased linearly with age (P < 0.001). Enrichment did not affect social play or locomotor play during lactation. Enrichment did not influence the amount of skin lesions before weaning, but heavier piglets had more skin lesions (P < 0.01). The enrichment strategies had no influence on weight gain at any stage. The baseline of the salivary cortisol concentration was similar amongst the treatment groups; however, the cortisol concentration of the object group and control group was significantly higher at one day after weaning than at baseline (P < 0.001) whereas the substrate group showed no significant increase. In conclusion, providing either hanging objects or substrate alone could encourage neonatal piglets to express more object play behaviour. Compared to the hanging objects, providing substrate in the commercial neonatal environment demonstrated to decrease piglets’ stress at weaning, and therefore increase animal welfare.

Tail biting causes acute phase response and inflammation in pig tails

Tail biting induces a strong acute phase response and tail-end inflammation in finishing pigs. By Heinonen M, Orro T, Kokkonen T, Munsterhjelm C, Peltoniemi O, Valros A., 2010. Vet J. 184:303-7.


The extent of inflammation associated with tail biting in finishing pigs was evaluated. Tail histopathology, carcass condemnation and the concentration of three acute phase proteins (APPs), C-reactive protein (CRP), serum amyloid-A (SAA) and haptoglobin (Hp), were examined in 12 tail-bitten and 13 control pigs. The median concentrations of APPs were higher (P<0.01) in bitten (CRP 617.5mg/L, range 80.5-969.9; SAA 128.0mg/L, 6.2-774.4; Hp 2.8g/L, 1.6-3.5) than in control pigs (CRP 65.7mg/L, 28.4-180.4; SAA 6.2mg/L, 6.2-21.4; Hp 1.2g/L, 0.9-1.5). There was a tendency for APP concentrations to rise with the histopathological score but the differences were only statistically significant between some of the scores. Five (42%) bitten cases and one (8%) control pig had partial carcass condemnations owing to abscesses (P=0.07). The results show that tail biting induces an inflammatory response in the tail end leading to an acute phase response and formation of carcass abscesses.

Toys and tail docking may reduce stress from mixing of pigs after weaning

Teeth clipping, tail docking and toy enrichment affect physiological indicators, behaviour and lesions of weaned pigs after re-location and mixing. By Fu, Lingling, Zhou, Bo, Li, Huizhi, Allan P. Schinckel, Liang, Tingting, Chu, Qingpo, Li, Yuan, Xu, Feilong, 2018. Livestock Science 212: 137-142.


• Re-location and mixing after weaning brought stress to weaned pigs.

• Toy enrichment decreased the stress of mixing after weaning.

• Pigs with intact teeth and tail got more lesions after mixing.

• Weaner pigs with intact teeth and tail should avoid to be mixed after weaning.

Abstract Re-location and mixing after weaning increase the risk of aggression in weaned pigs. To quantify the effects of tail docking, teeth clipping and toy enrichment on the growth performances, behaviour, lesions, and physiological indicators of weaned pigs after re-location and mixing, a total of 262 weaned pigs from four pig processing treatments were selected and regrouped to two enrichment treatments within each processing treatment. The experimental newborn piglets from 24 litters were treated tail docking and teeth clipping at 3 d of age and weaned at 24 d of age. At 30 d of age, pigs in each treatment were weighed, re-located to a nursery room and mixed into 2 pens. Eight rubber toys were installed in one of two pens in each group. The behaviour of weaned pigs was recorded and observed at 1, 2 and 3 d after mixing. At 3 and 6 d before mixing and 1, 3 and 6 d after mixing, lesions on the body and tail, body surface temperature (BST), respiration rate (RR) and salivary cortisol concentrations were determined. At 85 d of age, all experimental pigs were weighed again. Mortality rate, average daily gain (ADG), and feed efficiency of pigs were recorded. Pigs with clipped teeth performed less negative social behaviour (aggressive attacks/fight) (P < 0.05) and more positive social behaviour (non-aggressive social interactions) (P < 0.01) than pigs with intact teeth. Pigs with docked tails performed more positive social behaviour (P < 0.01) than pigs with intact tails. Toy enrichment decreased (P < 0.05) lesions on the ear and front body of pigs, and pigs with docked tail got fewer lesions on the tail (P < 0.01). Intact teeth increased (P < 0.01) RR, while toy enrichment decreased (P < 0.05) RR of pigs. Teeth clipping, tail docking and toys had no effects (P > 0.05) on ADG, body weight and mortality rate of pigs from 30 to 85 d of age. These results indicate that toy enrichment and pig processing treatments have positive effects on weaned pigs after re-location and mixing.

Risk factors for tail lesions in weaner pigs

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


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

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

Data interpretation should include information on correlations between variables.


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

Early indicators of tail biting in pigs

Early indicators of tail biting outbreaks in pigs. By Maya Wedin, Emma M. Baxter, Mhairi Jack, Agnieszka Futro, Richard B. D’Eath.
Applied Animal Behaviour Science: 208: 7-12


Tail biting in pigs is unpredictable so early indicators could help farmers.•

Behaviour of tail biting vs no tail biting groups observed for 1 week pre-outbreak.•

Outbreak groups had fewer curly tails and more tucked tails.•

Activity pre-outbreak was no different in outbreak groups.•

Day and time of day had little or no effect on these findings.


Tail biting outbreaks in pig farming cause suffering through pain and stress, and producers lose revenue due to carcass condemnation. Reliable behavioural indications of when an outbreak is imminent would provide farmers with tools for mitigating the outbreak in advance. This study investigated changes in body and tail posture in the 7 days pre-outbreak.

Pigs in 15 groups with a mean (±s.d.) group size of 27.5 (±2.6; 427 in total) were raised from birth under intensive commercial conditions and with tails intact. Twice daily inspections were made, and a tail biting outbreak was identified (and treated) if 3 or more pigs had fresh tail injuries, or any pig was seen with a freshly bleeding tail or vigorously biting a tail. Video footage was recorded continuously to allow pre-outbreak behaviour recording of body posture (lying laterally, lying ventrally, sitting, standing) and tail posture (curled or uncurled (high, low, tucked)). Pigs were not individually marked, thus observations were made at pen level by group scan sampling 12 times per day on day -1, -3, -5 and -7 pre-outbreak. Each outbreak group was paired with a non-outbreak group of the same age and kept at the facility at the same time which served as a control. A total of 12 pairs were used. Outbreak pigs had fewer curled tails (P = 0.013) and more uncurled (P = 0.008) and tucked tails (P < 0.001) than control pigs overall, but particularly on day -1. Outbreak groups had more tucked tails compared to control on day -7 (P = 0.001). Tail posture did not vary over days, or with time of day. Body posture was not different between outbreak and control groups, and although it was affected by time of day, there was no interaction between outbreak vs. control condition and day, or time of day. Synchrony of behaviour between pigs (more pigs in the pen showing the same body posture) was not reduced in outbreak groups. In conclusion, this study supports other recent findings showing that an increase in tucked tails, and reduced curled tails is an advance indicator of a tail biting outbreak giving at least 7 days warning, and it does not matter what time of day tails are observed. Pig farmers could take note of tail posture changes to identify high risk pens. Considerable variability between pens, and in the timing and magnitude of change means that technology to automate tail posture detection will be of benefit.

Optical flow to monitor tail biting outbreaks in pigs.

Utilization of optical flow to monitor development of tail biting outbreaks in pigs. By Y Li, H Zhang, L Johnston, M Dawkins, 2018. Journal of Animal Science 96: 519.


This study was conducted to evaluate activity changes in pigs associated with outbreaks of tail biting using an optical flow platform. Pigs (n=240, 24.9 ± 2.9 kg, 9-wk old) were housed in 8 pens of 30 pigs on slatted floors for 16 weeks. Four pens housed pigs with tails docked and the other 4 pens housed pigs with tails intact. Pigs were assessed for tail scores (0=no injury to 4=severe injury) once weekly. Behaviors of pigs were video-recorded twice weekly. One-hour video segments during morning, noon, and afternoon of each recording day were analyzed for optical flow using the OPTICFLOCK platform which measures movements of pigs in each pen. The same video segments were scanned at 5-min intervals to estimate time budget for standing/walking, lying, eating, drinking, and tail biting. Compared with docked pigs, intact pigs had higher tail scores (0.5 ± 0.29 vs. 0.1 ± 0.01; P < 0.001) and higher optical flow (8.2 vs. 6.9; SE=0.42; P < 0.05), suggesting more tail injuries and higher activity levels. Intact pigs spent less time lying (P < 0.001) and more time eating (P < 0.01) and tail biting (P < 0.01), and tended to spend more time standing/walking (P=0.08) than docked pigs, which support the optical flow data. During outbreaks of tail biting, intact pigs had higher optical flow during the first outbreak (14.59, SE=0.73; P < 0.05) compared to before (5.44) and after (10.54) the outbreak, suggesting activity changes during the development of tail biting outbreaks. Across tail docking treatments and observation days, pigs had lower optical flow at noon (6.9, SE=0.33; P < 0.001) compared to morning (7.8) and afternoon (7.9), suggesting that pigs were less active at noon which was supported by the behavioral time budgets. These results suggest that optical flow might be a promising tool for monitoring activity changes in pigs during the development of tail biting.