Vice (tail-biting, flank chewing, ear biting)

calendar icon 8 November 2018
clock icon 8 minute read

Background and history

Vice in both weaned and growing pigs can be a major problem on some farms with considerable economic loss.

Why do pigs mutilate each other? From our own experiences poor environmental conditions and human interactions cause varying degrees of aggravation and this is no different in the pig. If there is a problem on the farm, consider the three major contributing factors; management, nutrition and disease.

Vice in the dry sow is confined to vulval biting particularly in the last 3 to 4 weeks of pregnancy. This can be a major problem in loose-housed sows and in badly managed systems there may be 80% of all sows in a herd with the vulva completely bitten off. Severely traumatised vulvas heal with scar tissue and this can cause constrictions and difficulties at farrowing.

The weaned pig

  • Penis / navel sucking..
  • Prepuce sucking.
  • Ear sucking..
  • Tail biting.


  • Tail biting.
  • Ear necrosis.
  • Chewing feet.
  • Flank biting.


  • Vulval biting See disease listing


  • Prepuce sucking

Clinical signs

Weaners and growers

  • Evident by trauma and infection of the skin - Dermatitis.
  • Lameness.
  • Mortality.


  • N/A

Sows (See vulval biting)

  • Swollen / torn vulva.
  • Evidence of blood on the skin and noses of the sows highlight the possibility of this condition.
  • Severe haemorrhage with loss of life in a few animals.
  • Low grade infections.
  • Ascending womb infections.
  • Increased repeats.
  • Scar tissue.


Based on observations and skin lesions.



Where there is competition for food or poor access, this tends to create aggression in the pen. Observations have shown that there is a greater tendency to tail biting when automatic feeders are used compared to manual systems. With automatic systems there is little empathy between pig and person. Increasing the salt level in the diet to 0.9% can often produce an improvement. Make sure there is ad lib water available.

Nutritional deficiencies:

  • Low salt in the diet.
  • Inadequate nutrition.
  • Diet changes.

Poor feed availability caused by:

  • Feeding pellets.
  • Rations with small particle sizes.
  • Disease factors


Greasy pig disease or exudative epidermitis is a little realised but important factor in the development of both tail biting, ear and flank chewing. A skin infection or wet eczema starts on the tip of the tail or ears with small areas of serum oozing to the surface. This is often initiated by a combination of feed contaminating the skin and splitting of the skin caused by trauma. Staphylococcus hyicus then invades and causes infection. The pig is attracted to the lesion and eventually this leads to vice. This situation is particularly apparent when pigs are first weaned into flat decks or nurseries or when they are moved into second stage accommodation particularly if mixing takes place. New concrete has an alkaline surface and the high pH and prolonged pressure to the skin, particularly when the pig is lying on slats, causes sores to develop over the ham or flanks. This can lead to infection and then vice. Greasy pig lesions on the tail are an irritant causing considerable tail movement which becomes attractive to other pigs. Other diseases such as pneumonia can result in disadvantaged pigs being traumatised by others.

  • Colitis.
  • Greasy pig disease.
  • New concrete and skin trauma.
  • Parasites.
  • Pneumonia.
  • PRRS skin lesions.
  • Skin trauma.
  • Swine pox.
  • Wet eczema.


  • A very humid environment.
  • Long tails.
  • Aggressive breeds.
  • Draughts.
  • No bedding.
  • Fluctuating temperatures.
  • Trauma.
  • High air speed
  • Uncomfortable conditions.
  • High stocking densities.
  • Unhappy pigs.
  • Shortage of trough space.
  • Water shortage.
  • Ammonia levels > 20ppm.
  • Wet pens.
  • Automatic feeding and little human/pig empathy.
  • High hydrogen sulphide levels > 10ppm.
  • Pigs too small for the environment.
  • Bad pen designs - badly sited feeders.
  • High carbon dioxide levels > 3000ppm.
  • Nutritional factors.


  • Identify and correct the causal factors outlined above.
  • Spray pigs with a 1% skin antiseptic, such as savlon, when housing is changed and continue this daily for two days.
  • Spraying with a heavy industrial scent will help to reduce fighting when pigs are mixed.
  • If Staphylococcus hyicus infection is part of the problem there will usually be a very good response to in-feed medication with tetracyclines.
  • Remove traumatised pigs from the pen to straw based accommodation immediately.
  • Isolate offending pigs.


  • Determine the antibiotic sensitivity of the Staphylococcus hyicus if this is part of the problem and medicate feed for 7 to 10 days. Assess the results of strategic medication.
  • Inject traumatised pigs with long-acting preparations of penicillin or OTC, or amoxycillin.

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