Knowledge
Dossier: Tail biting and tail docking
Background information and practical knowledge on the understanding of the origin of tail-biting, how it affects pig welfare, and how tail docking can be avoided in practice.
Tail biting and origin:
- What is tail biting?
- Which stages of tail biting can be identified?
- Why do pigs bite tails?
How to prevent tail biting? Risks of tail biting can be considerably reduced if correct management measures are introduced. Six key factors are:
- Adequate enrichment
- Comfortable climate
- Good health status
- Limit competition over resources
- Balanced diet
- Adequate pen structure and cleanliness
Tail biting and origin
What is tail biting?
Tail biting is an abnormal behaviour, involving the biting of pigs in the tails of their penmates, resulting in tail injuries. It is a response to boredom, insufficient stimulation, and frustration related to negative environmental and management factors that can increase pigs’ stress levels.
Relevant links
Stages of tail biting
Tail biting typically occurs in different stages, called ‘pre-injury tail chewing’, ‘damaging stage’ and finally ‘cannibalism’.
Read more & links
Stages:
- Pre-injury tail chewing is difficult to detect based on inspection of the tails, but early signs include hanging/clamped tails, tail wagging, hairless tails (there should be a clear plume of hair at the tip of the tail), and restlessness;
- In the damaging stage, biting is more forceful, blood is present from wounded tails and the behaviour escalates within the group.
- Later on, more severe injuries are visible and larger parts of the area around the tail may have been eaten away: at this stage it is called cannibalism.
Relevant links
- Talking Tails - Quantifying the development of tail biting in pigs, Thesis J. Zonderland, 2010
Why do pigs bite tails?
Tail biting is a multi-factorial problem, i.e. many risk factors may contribute to it and fill up the farm’s ‘cumulative risk bucket’. At a certain point, the bucket overflows, and tail biting starts.
Read more & links
The main (six) risk factors that go in the bucket are:
- Inadequate environmental enrichment;
Inadequacies in other management measures:
- Thermal comfort and air quality
- Health status;
- Competition over resources;
- Diet;
- Pen structure and cleanliness
Relevant links
- Cutting the need for tail docking, Leaflet European Commission (no date)
- Different housing and husbandry systems and risks for tail biting, Scientific Opinion EFSA, 2007
How to prevent tail biting? Six key factors
Adequate enrichment
Pigs need enrichment materials to fulfill their needs for rooting, sniffing, biting and chewing:
- Key qualities of enrichment materials are: safe, edible, chewable/bitable, investigable, and manipulable;
- Provision: of sustainable interest, accessible, sufficient in quantity, and clean.
Read more & links
The Commission Staff working document categorizes enrichment materials as: ‘optimal’, ‘suboptimal’ and ‘marginal’:
- Optimal - can be used alone because they possess all the necessary characteristics to meet the pigs' needs;
- Suboptimal - can be used as an essential component of the pig’s enrichment but should be used in combination with other materials.
- Marginal - should not be used as essential or single component of pig enrichment materials.
Relevant links
- Pen enrichment, brochure in Dutch ‘Hokverrijking’, Kluivers-Poodt et al., 2019
- Enrichment for finishing pigs, Brochure of the EURCAW-Pigs “pre-project” EUWelNet (EUWelNet, No date)
- A Practical Guide to Environmental Enrichment for Pigs: a handbook for pig farmers, AHDB, 2017
- Manipulable materials and welfare assessment of pigs, scientific Opinion EFSA, 2014
Comfortable climate
Maintaining the right temperature, good air quality, and a day and night rhythm are extremely important in keeping stress and tail biting levels low.
Read more & links
Recommendations:
- Take into account that optimal temperatures differ with different weights and age of pigs;
- In cold climates, insulation, good bedding or a heating system can ensure thermal comfort;
- During warm weather, options include ground heat exchangers, air conditioning, floor cooling, misting systems, showers and wallows;
- Ventilation must limit the flow of cold air over sleeping areas and keep dust and CO2 and NH3 levels to a minimum;
- A day and night rhythm is realized by keeping pigs at light levels having an intensity of at least 40 lux, for a minimum period of 8 hours a day (required by law).
Relevant links
- Recommended climate settings for pigs, Dutch climate platform
- Different housing and husbandry systems and risks for tail biting, Scientific Opinion EFSA, 2007
Good health status
Good overall health is one of the best ways to reduce tail biting. A pig in poor health is a stressed pig.
Read more & links
(Preventive) Measures:
- Setting up a general herd health plan together with a veterinarian, including an appropriate vaccination scheme/ programme;
- Presence of a protocol to treat sick animals, including provision of an adequate number of hospital pens;
- Presence of a biosecurity protocol.
Relevant links
- Pig health compliance criteria, pig sub-group, in prep.
Limit competition
Pigs prefer to forage, eat and rest simultaneously. There should be enough space and resources for the pigs to allow synchronised behaviour and thereby avoid competition that can lead to tail biting.
Relevant links
Recommendations:
- Feeding systems that allow all pigs to eat simultaneously;
- Sufficient access to watering points. All drinkers should be checked regularly to ensure they are clean and working;
- All pigs in a group should be able to lie at the same time in lateral recumbency;
- Space allowances should enable pigs to maintain separate resting and activity areas, while offering pigs opportunities to escape from their pen-mates;
- Provision of manipulable materials in sufficient quantities, in reach and at multiple points.
Relevant links
- Space and competition compliance critera, pig-subgroup, in prep.
Balanced diet
Inadequacies in quality and quantity of food and water are implicated in the occurrence of tail biting.
Read more & links
Recommendations:
- Ensure a feeding plan (specified and evaluated by a feed specialist) to safeguard that nutritional specification is appropriate for the age/genetics of pigs;
- Ensure that pigs have an sufficient amount of feed, by checking whether the feeding system is properly functioning (e.g. the storage containers are filled, the pipes to the troughs are not blocked);
- Check the quality of feed, e.g. mould in a trough indicates that the feed is not appropriate;
- Ensure that pigs have continuous access to fresh water.
Relevant links
- Diet compliance criteria, pig-subgroup, in prep.
- Different housing and husbandry systems and risks for tail biting, Scientific Opinion EFSA, 2007
Pen structure/cleanliness
Pigs prefer to keep different areas of the pen for different behaviours (resting, feeding, defecation). A dirty environment, especially in the feeding and resting area, is therefore a sign that something is wrong. It also, in turn, reduces comfort and stresses the pigs.
Read more & links
Measures:
- Create well-defined areas for resting, feeding and dunging;
- Experiment with temperature and ventilation (see “Comfortable climate”)
Relevant links
- Different housing and husbandry systems and risks for tail biting, Scientific Opinion EFSA, 2007