Tail biting constitutes a major welfare and health issue in commercial pig rearing, with significant negative economic consequences. Contrary to the aim of the EU directive (2001/93/EC), tail docking is still widely practiced in most EU countries as a measure to reduce the incidence of tail biting and concomitant pathologies. Mutilations are a general welfare concern in all species, and any efforts towards reducing the need for tail docking are important for the future sustainability of the EU pig sector. Sound policy making needs science-based risk assessment, including assessment of the severity of problems and effectiveness of solutions. The general objectives of the FareWellDock-project included estimation of the relative harms associated with tail docking and tail biting, and evaluation of the efficacy of some main preventive measures against tail biting, which could reduce the need for tail docking. The ultimate aim was to stimulate the development towards a non-docking policy in the EU.
The first objective of WP1 was to evaluate measures of acute and chronic pain in relation to tail damage. This included assessment of the short (acute trauma), medium (post trauma inflammation) and long term (traumatic neuroma formation) pain associated with tail docking in neonatal piglets, and the possible consequences for longer term fear of humans. In addition, the studies assessed the effects of tail-damage in more mature pigs to provide a basis for assessing the pain associated with being tail bitten in later life. Finally, studies were conducted to assess the effects of an NSAID analgesic on the short term responses to neonatal tail docking.
Experimental studies confirmed that piglets do experience pain when tail docked, and that pain relief treatment, such as meloxicam, can lessen but not abolish the physiological stress reaction to docking. Piglets which have been tail docked seem more fearful of people afterwards than undocked animals. In docked tails, no difference in pain sensitivity of the tail (as measured by behavioural withdrawal) is detected after 8 weeks, but changes in the functioning of the sensory nerves from the tail can still be measured after 4 months, which suggests that the possibility for longer term pain exists. When the tail is damaged later in life, as happens with tail biting, changes in both tail stump sensitivity and nerve functioning can last for at least 4 months, and possibly beyond.
WP2 focused on the role of manipulable material when reducing the need for tail docking. The aim was to develop and validate ways to assess if on-farm use of manipulable material is sufficient to reduce tail biting. Further, the aim was to describe suitable methods for implementing the use of straw under commercial farming conditions and to investigate, in on-farm conditions, the efficiency of tail docking vs. enrichment given in sufficient quantity to reduce the occurrence of tail lesions.
A screening method to assess the appropriateness of the level of enrichment on-farm was developed and includes scoring of the amount of unsoiled straw, the behaviour, and ear, tail and flank lesions of the pigs. AMI (animal-material interaction) sensors were used e.g. to show that pigs in biter pens were more interested in novel ropes than pigs in control pens, that environmental enrichment may reduce exploratory behaviour of point-source objects, and that sick pigs, experimentally infected with streptococcus spp, were less interested in chain manipulation. The sensors appear to be a promising tool to assess the use of manipulable material by pigs. In countries (SE and FI) where tail docking is not done, farmers report using on average of 30 to 50 g of straw/pig/ day, equivalent to about 0.5 L/pig/day. A survey in SE revealed fewer injurious tail biting outbreaks on farms using larger amounts of straw. Larger amounts of straw were mainly used on farms having scrapers in the slurry channels. A large experimental study showed that a moderate amount of straw (150 gr/pig/day) reduced injurious tail-biting outbreak in finisher pigs by more than 50%, while docking seemed to be more effective as it reduced tail biting by more than four-fold. The effect of both measures was additive, i.e. docking and straw reduced tail biting 9 fold. Further, it was shown that increasing the amount of straw from 10 to up to 400 gr/pig/day had multiple positive effects by progressively reducing the occurrence of tail injuries and stomach ulcers, increasing growth rate, increasing straw-directed behaviour, and reducing redirected behaviours towards other pigs.
In WP3 the aim was to clarify the role of poor health in the causation of tail biting and victimization, and the aim was study early identification of tail-biting outbreaks. In addition, the aim to develop automated systems for early warning of tail biting outbreaks.
The results of experimental and on-farm studies showed that the social behaviour of sick pigs differs from healthy pen mates, as pigs with osteochondrosis received more sniffing and tail bites from their pen mates than healthy pigs, while pigs with mild respiratory disease tended to bite more at the ears and tails of pen mates than healthy pigs did. In addition, studies of cytokines suggest that low-grade inflammation may decrease activity and increase receiving sniffs and attacks from other pigs. Studies on data sets from commercial pig farms indicated that changes in feeding behaviour may be an important sign of an increased risk for tail biting to occur: Future tail bitten individuals showed a reduced feed intake already 2-3 weeks before tail damage became evident. Furthermore, feeding behaviour in groups which develop tail biting may differ from non-biting groups for at least ten weeks prior to an injurious tail-biting outbreak. It was also shown that tail-chewing activity may start 2-3 weeks before tail damage can be seen. A detailed behavioural study of tail biting events revealed that there appears to be no such thing as a ‘typical’ tail-biting event and that the behaviour shown immediately before a tail-biting event does not differ from behaviour prior to another type of social interaction, namely ano-genital sniffing. Thus, it seems difficult to predict if a social event will escalate into tail biting or not. However, tail biting is more likely between pigs that have previously interacted. Data sets from several countries and studies indicated an association between tail-biting damage and tear staining, but the direction of this association is not clear.
In summary the project concluded on a set of practical recommendations, which have been published as part of four factsheets on the FareWellDock-webpage:
- Avoid tail docking whenever possible because it definitely causes pain, induces long-term changes in sensory-nerve function and may impair the pigs’ confidence in humans.
- Avoid tail biting, and hence the need for tail docking, by addressing risk factors on the farm.
- Treat tail-bitten pigs promptly and consider pain relief.
- To reduce injurious tail-biting outbreaks, use straw as it might be almost as effective as tail docking. For this purpose, the more straw the better.
- To ensure that sufficient straw is allocated check that there is left-over straw before the next day’s allocation.
- Keep your pigs healthy. This will be good both for productivity and also help avoid injurious tail-biting outbreaks.
- If pigs show signs of illness, be more alert to tail biting risk.
- Remove tail-bitten pigs promptly to avoid further damage and treat according to veterinary advice.
- Pay special attention to groups of pigs where you see:
- high or suddenly increased levels of general activity or exploration
- tail manipulation or chewing
- swinging or tucked tails
- low or decreasing numbers of visits to an automatic feeder or reduced feed intake
Information on project activities and publications have been continuously published on the FareWellDock-webpage. To date, 16 scientific articles have been published, and 9 are in preparation. Communication to stakeholders has been active, both through the FareWellDock-webpage, including 97 blog posts, and by interviews in media in different countries, popular articles and presentations at producer seminars. In October 2016 the results were presented widely at the EU level to policy makers and other stakeholders at the ‘Meeting and Webinar on Actions to Prevent Tail biting and Reduce Tail docking of Pigs’, organized by the European Commission Directorate General for Health and Food Safety in Grange, Ireland.
Due to the positive experience of the cooperation a decision was made at the last project meeting in DK in October 2016 that we will continue our cooperation as the FareWellDock-network, also inviting further researchers and stakeholders to join. The first activity of the FWD-network will be to organise a satellite meeting at the Congress of the International Society for Applied Ethology in August 2017 in DK, and to launch an emailing list to make sure FWD-network members and other researchers keep updated on research progress and related topics.