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Vice - Abnormal Behaviour (Tail Biting, Flank Chewing, Ear Biting).

(461) Vice (abnormal behaviour Fig.9-37) 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.


Stand for a few minutes and observe pigs that are either tail biting or ear chewing and you will see that there is one overriding feature, the pigs give the impression of being very unhappy. The pig is indicating that the environment provided is far from ideal. The management factors that contribute to this are listed in Fig.9-38.

Study these, identify important ones and make changes until there is a response. Remove offending pigs from the group because once the vice has become an established habit it can be difficult to stop.


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. (Fig.9-39).


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. (Fig.9-40).


  • 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.
Management control and prevention
  • 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.

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