Tail biting, tail docking and Animal Welfare

Tail biting is a serious problem that production centres intend to prevent. Not only due to the economic loss it causes, but also because it compromises the well-being and health of the animals.

Tail biting involves destructive chewing of the tails of pigs and is caused when a bleeding bitten tail becomes attractive to other animals in the same group. Lots of factors can trigger this behaviour, internal and external. Tail biting is mostly the result of boredom, insufficient space (high stocking densities) and stimulation, and frustration. It occurs mainly in fattening pigs and when they cannot express their natural behaviour or are not provided with the adequate conditions (factors such as feed intake, poor environment and bad air quality).

Principal consequences of tail-biting:

  • Lower carcass weight, condemned and trimmed.
  • Economic loss.
  • Health issues.
  • Antibiotic usage.

There are many strategies to prevent tail biting. One of the most problematic ones is tail docking as it can cause an acute stress response and worsen the health of the animals. This post clarifies the critical points we must pay attention to if we want to prevent tail biting, to guide the decision-making process if we finally adopt tail-docking and specify the effects this measure brings.

Tail docking

Tail docking is considered a non-desirable measure to prevent tail biting among pigs for animal welfare concerns.

» The effectiveness of tail docking in preventing tail biting is limited, since it reduces the symptoms of a behavioral disorder, but does not address the underlying causes.

Although from a practical standpoint the welfare risks arising from tail docking may appear to be negligible compared to those arising during and after tail biting outbreaks, it should be considered that, apart from acute physiological and  behavioral  responses,  tail  docking  may also elicit long-term effects on weight gain, tail stump  sensitivity  and  animal  freedom  to express their normal behavior. Such chronic effects  have  been  poorly  investigated  so far, which is why we must consider deeply to adopt tail docking and take this measure.

tail docking

Responses to tail docking

Acute responsesLong-term effects


Other blood parameters

Behavioral responses


Weight gain

Chronic pain



Behavioral redirection

Decision tree to adopt tail docking

decision tree tail docking

Tips to prevent tail biting and avoid tail docking

1. Enrinchment material

Potential indicators of ineffective or insufficient:

  • Bitten tails
  • Skin lesions
  • Loss of interest
  • Rooting in dung
  • Competition for use of enrichment materials
  • Belly nosing


  • Long chopped straw
  • Alfalfa
  • Hemp rope
  • Change the place
  • Chewable
  • Root in it

Why? Explore the environment: Rooting, sniffing, biting and chewing

When? All pigs, all times

How much does it cost?

  • 25% of costs in fattening
  • 8% to 4% in breeding units

Enrichment material: When is it enough?

How do I know if I’m doing it right?

First and foremost, look at your pigs! Are they interested in the material you have provided, or are they manipulating other pigs or pen fittings instead? Are they competing for the material?

Are there any disadvantages?

Straw and roughage can also be used in pens with slatted floors – countries rearing pigs with intact tails report that when using these materials, slurry blockages are rare. Be aware of the origin of the enrichment material to avoid introducing contagious diseases within the production system

100% – 86.4%86.3% – 18.1%18% – 0%
Maximum exploratory behaviour – no additional material requiredIntermediate exploratory behaviour – no additional material required, altough you may want to reconsider if your figure is close to the lower endMinimal exploratory behaviour – introduction of enrichment materials recommended
  • When the pigs are active but not eating, count the number of pigs exploring (manipulating, investigating, chewing) enrichment material. This figure corresponds to ‘A’.

  • Count the number of pigs interacting with other pigs and pen fittings (do not include eating and drinking). This figure corresponds to ‘B’.

  • Substitute the letters in this equation with your figures: A/A+B. So if you observe 20 pigs exploring the enrichment material, with an additional 10 pigs interacting with other pigs or fittings, your sum would be 20/30. Now multiply that answer by 100 to give you a percentage. In this case it would be 66.7 %.

poor conditions farm

Image: Farms with poor conditions that worsen Animal Welfare

If a tail-biting outbreak occurs, it is important to immediately provide the pigs with a lot of distraction. A mixture of different, interesting and manipulable materials can help. Try using some of the following: branches with leaves, ropes (with knots), wood chip, hay, straw, or other edible material.

2. Thermal comfort, air quality and light

Potential indicators of poor quality

  • Lack of cleanliness
  • Restlessness/aggression
  • Huddling
  • Shivering
  • Playing with water and manure
  • Reduced appetite
  • Pigs laying on their sides and/or far apart
  • Defecating in the resting area
  • Panting, sneezing or coughing
  • Conjunctivitis


  • Temperature
  • Lack or high air flow over sleeping areas
  • Dust, ammonia, CO2
  • No direct sunlight
  • 40 lux for 8 h a day

Why? Limited capacity to regulate body temperature


  • Automatic reliable heating systems
  • Curtains in windows
  • No in semi-darkness

How much does it cost? Depending on the country

CO2Max of 3000 ppmVentilation efficacyMin / max
NH3< 20 ppmHygienePits
COz< 10 ppmHeating system
CH40 ppmFermentationPits
SH20 ppmToxicity for people and pigs
Dust< 2.4 mg/m3Particle size and concentrationThe lower the worst. Less than 5 µ arrives to lung alveolus

3. Sanitary conditions and diet

Article about Sanitary conditions, diet and amino acid supply over damaging behaviour: A link between damaging behaviour in pigs, sanitary conditions, and dietary protein and amino acid supply

Treatments (from weaning to slaughter):

  • 2 sanitary conditions, Low and High
  • 2 protein levels, Low and High
  • 2 amino acid supplementation levels:
    • 20% more of Thr, Trp and Met
  • 8 groups in total
  • 576 pigs, 64 pens, 8 pens per treatment, 9 pigs per pen

4 rooms for each sanitary condition

Sorted by weight

2 pens per diet and room

4. Health and fitness factors to prevent tail docking in pigs

What? Regular and planned visits of your trained veterinarians

Why? Avoid tail biting and business profit


  • Weaning at 28 days
  • Hygiene
  • Vaccinations
  • Analyses
  • Biosecurity
  • Health replacements
  • How much does it cost?: Outweighed by the benefits

5. Competition signals

Potential indicators of poor quality:

  • Low body condition scores
  • Variability in body size within a pen
  • Skin lesions on hind quarters (food competition)
  • Skin lesions on forequarters (space competition)
  • Fights around feeders
  • Pigs waiting to use feeders
  • Poor distribution of pigs in each area of the pen


  • Enough space for each pig for food, drink and space to rest
  • Pen structure
  • Pen allowances
  • Areas to feed, rest, play, toilet area


  • Stress
  • Confrontation
  • Pigs like to forage and feed together


  • Similar size of pigs in a pen
  • At weaning, mixing minimized
  • Keep litter mates together as much as possible
  • Move small piglets to a pen with extra facilities

How much does it cost?

  • Depending how good or bad facilities you have or how many pigs are with tail bitten
  • 17 cm per piglet (feeder)
  • 22 cm per fattener (feeder)

6. Diet

Potential indicators of poor quality:

  • Low body condition score
  • Variation in weight
  • Poor carcass classification
  • High incidence of stomach and intestinal ulcers
  • High incidence of tail or ear necrosis


  • Dietary fiber, NDF, ADF, NSP, soluble, insoluble, …
  • Tryptophan
  • Water
  • Salt and electrolytic balance

Why? High performance


  • Formulation
  • Particle size
  • Sugar beet pulp or similar raw materials (fiber structure)
  • 1 drinker/12 pigs
  • Flow rates and quality

How much does it cost?

  • Depending how good or bad facilities you have or how many pigs are with tail bitten
  • 17 cm per piglet (feeder)
  • 22 cm per fattener (feeder)

7. Pen structure and cleanliness contitions to control that will prevent tail biting

Potential indicators of an unsuitable pen structure/lack of cleanliness:

  • Presence of manure on the pigs’ bodies
  • Increased disease (lameness, diarrhoea, respiratory infections).


  • Increase level of noxious gases
  • Increasing risk of disease
  • Overcrowding
  • Uninteresting enrichment material when dirty


  • Well defined areas for resting and dunging specially in pens with partial slatted floor
  • Feeding, watering and resting areas should be clean at all time


  • Investigate pen layout
  • Draughts of air
  • Where does pig defecate?


  • Heated floors in resting areas
  • Remove dust and ammonia

When things are wrong...

First signs:

  • Hanging, clamped tails
  • Tail wagging
  • Hairless tails,
  • Restlessness and bite marks

Remove the biter and treat injured pigs, add fresh enrichment material (such as rope, fresh wood, branches, straw,...), and check the key factors reviewed before.