Tail docking involves amputating a portion of the tail for a variety of reasons. We review the scientific evidence for the rationale for tail docking, a description of the different methods used, the pain response to the procedure and the effectiveness of pain alleviation, and, finally, the alternatives to tail docking and policy regarding the practice. We focus on the three main agricultural species that are tail docked as a management practice: pigs, sheep, and dairy cattle. Methods of tail docking include cutting with a knife or scalpel, cutting with a hot docking iron, or application of a constrictive rubber ring. All methods are commonly performed without analgesia or anaesthesia, and all likely result in some degree of pain. As with any procedure that alters the integrity of an animal, it is important to consider the rationale behind docking in order to evaluate if it is necessary. Tail docking in pigs is routinely conducted on commercial swine farms because it can reduce the incidence of tail biting, an injurious and undesirable behaviour. Both behavioural and physiological changes indicate that tail docking is painful in pigs, but until robust and consistent methods for preventing tail biting are identified, this procedure is likely to continue as a management practice. This approach is reflected in public policy about the procedure. There is both behavioural and physiological evidence that tail docking is painful for sheep; both responses are reduced when pain relief is provided. Prevention of fly strike is the primary reason given for tail docking sheep, but the scientific evidence to support this rationale is surprisingly sparse. Further research is required to justify tail docking of sheep as a routine practice. Dairy cattle are docked because this practice is thought to improve cow cleanliness and udder health, however, there is no scientific evidence supporting this rationale. Tail docking cattle results in relatively few behavioural or physiological indicators of pain, but docked cows are unable to effectively remove flies from their hind end. The practice of tail docking dairy cattle is banned, discouraged or declining in most industrialized countries except the US. The long-term pain associated with tail docking is not well understood in pigs, sheep or cattle. In cases where tail docking may be justified by demonstrated benefits for the animal (possibly in case of pigs and sheep), further research is needed to find either practical alternatives or ways to alleviate the pain associated with this procedure.
Antibiotics (AB) are used in intensive pig production systems to control infectious diseases
and they are suspected to be a major source of antibiotic resistance. Following the ban on
AB use as growth promoters in the EU, their prophylactic use in-feed is now under review.
The aim of this study was to evaluate the effect of removing prophylactic in-feed AB on pig
health and welfare indicators. Every Monday for six weeks, a subset of 70 pigs were
weaned, tagged and sorted into two groups of 35 pigs according to weight (9.2 ± 0.6 kg). AB
were removed from the diet of one group (NO, n = 6) and maintained in the other group (AB,
n = 6) for nine weeks. Ten focal pigs were chosen per group. After c. five weeks each group
was split into two pens of c.17 pigs for the following 4 weeks. Data were recorded weekly.
Skin, tail, ear, flank and limb lesions of focal pigs were scored according to severity. The
number of animals per group affected by health deviations was also recorded. The number
of fights and harmful behaviours (ear, tail bites) per group was counted during 3×5min
observations once per week. Data were analysed using mixed model equations and binomial
logistic regression. At group level, AB pigs were more likely to have tail (OR = 1.70; P =
0.05) but less likely to have ear lesions than NO pigs (OR = 0.46; P<0.05). The number of
ear bites (21.4±2.15 vs. 17.3±1.61; P<0.05) and fights (6.91±0.91 vs. 5.58±0.72; P = 0.09)
was higher in AB than in NO pigs. There was no effect of treatment on health deviations and
the frequency of these was low. Removing AB from the feed of weaner pigs had minimal
effects on health and welfare indicators.
Indirect genetic effects (IGEs) are heritable effects of an individual on phenotypic values of others, and may result from social interactions. We determined the behavioural consequences of selection for IGEs for growth (IGEg) in pigs in a G × E treatment design. Pigs (n = 480) were selected for high versus low IGEg with a contrast of 14 g average daily gain and were housed in either barren or straw-enriched pens (n = 80). High IGEg pigs showed from 8 to 23 weeks age 40 % less aggressive biting (P = 0.006), 27 % less ear biting (P = 0.03), and 40 % less biting on enrichment material (P = 0.005). High IGEg pigs had a lower tail damage score (high 2.0; low 2.2; P = 0.004), and consumed 30 % less jute sacks (P = 0.002). Selection on high IGEg reduced biting behaviours additive to the, generally much larger, effects of straw-bedding (P < 0.01), with no G × E interactions. These results show opportunities to reduce harmful biting behaviours in pigs.
By Yuzhi Li, Haifeng Zhang, Lee. Johnston and Wayne Martin 2018. Animals 2018, 8(1), 13
The objective of this study was to investigate the association between social structure and incidence of tail-biting in pigs. Pigs (n = 144, initial weight = 7.2 ± 1.57 kg, 4 weeks of age) were grouped based on their litter origin: littermates, non-littermates, and half-group of littermates. Six pens (8 pigs/pen) of each litter origin were studied for 6 weeks. Incidence of tail injury and growth performance were monitored. Behavior of pigs was video recorded for 6 h at 6 and 8 weeks of age. Video recordings were scanned at 10 min intervals to register pigs that were lying together (1) or not (0) in binary matrices. Half weight association index was used for social network construction. Social network analysis was performed using the UCINET software. Littermates had lower network density (0.119 vs. 0.174; p < 0.05), more absent social ties (20 vs. 12; p < 0.05), and fewer weak social ties (6 vs. 14, p < 0.05) than non-littermates, indicating that littermates might be less socially connected. Fifteen percent of littermates were identified as victimized pigs by tail-biting, and no victimized pigs were observed in other treatment groups. These results suggest that littermates might be less socially connected among themselves which may predispose them to development of tail-biting.
An EC meeting in Grange, Ireland (28-30 November 2017) gathered information about EU initiatives to reduce tail biting and tail docking in pigs. Presentations of the meeting (incl webinar) can be found via the CIRCABC-website.
EU legislation on the welfare of pigs (Council Directive 2008/120/EC laying down minimum standards for the protection of pigs) does not allow routine tail-docking and requires farmers to provide to their pigs “manipulable material” such as straw, hay or sawdust.
To better inform farmers how to prevent routine tail docking, the Commission developed educational materials. The two videos present success stories in achieving the goal of rearing not-tailed pigs.
A Finnish farming with an intensive system rearing piglets with intact, curly tails.
An Italian farmer proud of rearing curly tails on straw
August 7, 2017 a very nice one-day meeting was held in Aarhus (DK) to discuss feather pecking in laying hens and tail biting in pigs. The meeting was a joint initiative of FareWellDock and GroupHouseNet. A Skype4business connection made it possible for about 10 external participants to join the meeting in addition to the 60 delegates present in person.
Opening of the meeting, introduction and networking session,
Anna Valros, Sandra Edwards
9:50-11:00 Theme 1: Mechanisms underlying the link between health and damaging behaviour
Invited speakers: Janicke Nordgreen (pigs), Jerine van der Eijk (poultry)
Mini research seminar
≥ Lisette van der Zande: The estimation of genetic effects of tail damage on weaned pigs and its influence on production traits
≥ Anja Brinch Riber: Link between feather pecking and keel bone damage
≥Mirjam Holinger: Does chronic intermittent stress increase tail and ear manipulation in pigs?
≥Laura Boyle: The effect of removing antibiotics from the diets of weaner pigs on performance of ear and tail biting behaviours and associated lesions
11:00-11:20 Coffee/tea break
11:20-12:20 Theme 1 continues: Group and plenary discussion, Anna Valros
12:20-13:20 Lunch break
13:20-14:30 Theme 2: Predisposing factors for damaging behaviour during early development
Invited speakers: Jo Edgar (poultry) and Armelle Prunier (pigs)
Mini research seminar
≥Ute Knierim: A tool to work on risk factors during rearing for feather pecking in laying hens
≥Elske de Haas, Margrethe Brantsæter & Fernanda Machado Tahamtani: Disrupting availability of floor substrate in the first weeks of life influences feather pecking during rearing and lay – a Dutch and Norwegian approach
≥Anouschka Middelkoop: Effect of early feeding on the behavioural development of piglets around weaning
≥Irene Camerlink: The crooked mind of the commercial pig: can we rectify abnormal biting behaviour by early and later life conditions?
14:30-14:50 Coffee/tea break
14:50-15:50 Theme 2 continues: Group and plenary discussion, Sandra Edwards
15:50 Closing of workshop
Some tweets from the workshop:
Acute lethal aggression is increasingly seen in commercial pig farming, as is excessive neonatal aggression (Irene Camerlink)
About 50 studies link (in-)adequate foraging to injurious feather pecking in poultry (Jo Edgar).
Maternal care strongly influences chick behavioural development (Jo Edgar)
Study: Lots of ear biting on Irish pig farms, up to 50% of pigs; Follow up: Antibiotic use may play a role (both causing & treating) (Laura Boyle).
Feather pecking appears to be linked to keel bone damage (Anja Brinch Riber).
Feather pecking is associated with elevated specific immune response (Jerine van der Eijk).
The tendency to reduce crude protein (CP) levels in pig diets to increase protein efficiency may increase the occurrence of damaging behaviours such as ear and tail biting, particularly for pigs kept under suboptimal health conditions. We studied, in a 2×2×2 factorial design, 576 tail-docked growing-finishing entire male pigs in 64 pens, subjected to low (LSC) vs. high sanitary conditions (HSC), and fed a normal CP (NP) vs. a low CP diet (LP, 80% of NP) ad libitum, with a basal amino acid (AA) profile or supplemented AA profile with extra threonine, tryptophan and methionine. The HSC pigs were vaccinated in the first nine weeks of life and received antibiotics at arrival at experimental farm at ten weeks, after which they were kept in a disinfected part of the farm with a strict hygiene protocol. The LSC pigs were kept on the same farm in non-disinfected pens to which manure from another pig farm was introduced fortnightly. At 15, 18, and 24 weeks of age, prevalence of tail and ear damage and of tail and ear wounds was scored. At 20 and 23 weeks of age, frequencies of biting behaviour and aggression were scored for 10×10 min per pen per week. The prevalence of ear damage during the finisher phase (47 vs. 32% of pigs, P < 0.0001) and the frequency of ear biting (1.3 vs. 1.2 times per hour, P = 0.03) were increased in LSC compared with HSC pigs. This effect on ear biting was diet dependent, however, the supplemented AA profile reduced ear biting only in LSC pigs by 18% (SC × AA profile, P < 0.01). The prevalence of tail wounds was lower for pigs in LSC (13 ± 0.02) than for pigs in HSC (0.22 ± 0.03) in the grower phase (P < 0.007). Regardless of AA profile or sanitary status, LP pigs showed more ear biting (+20%, P < 0.05), tail biting (+25%, P < 0.10), belly nosing (+152%, P < 0.01), other oral manipulation directed at pen mates (+13%, P < 0.05), and aggression (+30%, P < 0.01) than NP pigs, with no effect on ear or tail damage. In conclusion, both low sanitary conditions and a reduction of dietary protein increase the occurrence of damaging behaviours in pigs and therefore may negatively impact pig welfare. Attention should be paid to the impact of dietary nutrient composition on pig behaviour and welfare, particularly when pigs are kept under suboptimal (sanitary) conditions.
The aim of this study was to investigate the effects on tail-biting during rearing of housing piglets of the same litter compared to piglets from different litters. The treatments “litter-wise” (LW, n =240) and “mixed litters” (ML, n =238) were housed in five identical units. Each tail was scored regarding tail lesions and tail losses once per week with a four-point score (0= no damage/original length to 3= severe damage/total loss). The effect of week after weaning had highly significant influences on tail lesions (p<0.001). Tail-biting started in the second week after weaning, with an increasing severity during rearing. First tail losses were observed in the fourth week after weaning. The batch and the interaction between treatment and batch had highly significant influences on tail losses at the end of rearing (p<0.001). Depending on batch, piglets in the LW or ML treatment were more affected by tail-biting.