Tail Biting

Highlights of a presentation by Dr Mark Whitney of the University of Minnesota and tips, summarised by Doug Richards, Swine Grower-Finisher Specialist at Ontario Ministry of Food, Agriculture and Rural Affairs (OMAFRA) in that organisation’s Pork News and Views newsletter.
calendar icon 12 July 2012
clock icon 7 minute read

Anyone that has every walked through a pen of pigs knows that they are inquisitive, using their mouth to investigate their surroundings, coupled with a natural tendency to chew. This can lead to problems if animals exhibit signs of tail biting. It can seem to start without cause, involving one or two animals or whole pens of pigs.

Solving the tail biting problem may be as simple as removing the pig whose tail is being bitten or very complex with no obvious causes or solutions. The occurrence of tail biting may be almost non-existent or a never-ending problem. Tail biting can be a very costly event in any pig operation with no one guaranteed remedy to preventing or stopping the problem.

Dr Mark Whitney, University of Minnesota through an educational series entitled ‘Pork- Bridge—, presented a session on the subject of tail biting. The following are the highlights and tips from that presentation.


  • Pigs have a natural tendency to mouth and chew objects as a way of exploring their environment.
  • Research has shown that pigs are attracted to both the sight and taste of blood. If blood is drawn by accidental biting of a pen mate’s tail, it can become infectious to the animal that started the biting and if left unchecked, other pigs can join in.
  • Tail biting is costly to the pig industry through the loss of pig productivity, primary/ secondary infection, death loss and condemned carcasses.
  • Research studies show a relationship between tail biting and disease lesions and condemnations in slaughter plants.
  • Aberrant aggressive behaviour in pigs has been defined as a ‘vice’ in pigs by the BPEX in the UK. Tail biting is the largest problem of those defined vices.


  • When tail biting occurs, producers need to look at all possible causes and possible trigger factors.
  • Many factors can be at play including the environment, diet and husbandry methods that the pigs are responding to in a negative way.
  • One rogue pig biting other(s) or larger problems in pens of pigs, no one pig or cause identified.
  • Professional veterinary advice is essential to help in solving the problem.

Tail Biting Triggers

  1. Curiosity/Behaviour
  2. Production system type
  3. Tail docking protocol
  4. Stress

1. Curiosity/Behaviour

  • Tail biting as a vice activity caused by factors such as frustrated foraging activity or the normal investigation by mouth resulting in accidental bleeding of the pen mate’s tail.
  • Attraction to blood can result in more tail biting activity.
  • Some genetic lines may have more tendency to show this type of behaviour.
  • Research has shown gender differences, with barrows having their tails bitten 2.5 times more than gilts. Some speculation is that gilts turn around to face new pigs or situations while barrows turn away from new pigs or unsure situations, thus exposing their tail.

2. Production Systems

  • British research on the percentage of pigs affected by tail biting in different production systems looked at straw and slats; indoor and outdoor; breeder finisher, nursery finisher and finisher.
  • Pigs on straw were the lowest when compared to pigs raised on slats (0.4 per cent versus 2.1 per cent).
  • Indoor had a 50 per cent higher rate of occurrence than with outdoor (1.7 per cent versus 1.2 per cent).
  • Finisher operations had the highest incidents of tail biting at 1.6 per cent with breeder finishers at 1.1 per cent and the nursery at 0.9 per cent.
  • Straw can help reduce the incidence of tail biting by giving pigs something to chew on but will not work with most partial or total slat operations.

3. Tail Docking

  • Proper tail docking is the best method to reduce the incidence of tail biting. More tail biting problems may result when tails are left long or not docked properly. The last part of the tail is less sensitive to touch and the pig may not sense when a pen mate is chewing on the tail and seek to move out of harms way.
  • Docked tails should be uniform in length; it was reported that herds with variable tail lengths had more problems with tail biting.
  • Tails should have about two-thirds docked, leaving one-third of the tail when the baby pig is processed.

4. Stress

Any factor that increases the stress level in a pig or group of pigs can lead to tail biting issues:

Stocking rates

  • Increased stocking density and overcrowding increases the competition for food, water and pen space. Limited feeder/waterer space may cause forceful biting on the rear of pigs at the feeder/waterer as others try to gain access
  • Lack of pen space to lie down or get out of harms ways or having to walk over other pigs to feed or drink along with poor pen design or feeder placement can cause problems.
  • Canadian research has shown that group size is a factor with medium size pens of pigs (between 20 and 40 pigs) having the highest incidence, while the smaller or larger pens sizes had lower levels of tail biting. This is due to the hierarchy in medium size pens being the hardest for the pigs to sort out. In the end, it is best to have the recommended square footage for the size of pig.

Temperature variation

  • Excessive heat or cold can be a trigger. Proper winter ventilation/supplemental heat or pig misters in summertime heat can be beneficial.
  • Poor ventilation and draughts may result in pigs piling, having high humidity, dust, poor air quality or noxious gases which can lead to tail biting issues.


  • Today’s swine diets are well balanced but nutrition can be an issue. Your feed supplier can help with any concerns you have.
  • Poor feed quality or out of feed events with the latter being known to cause tail biting.

Health co-factors

  • Any health challenge going through the herd such as presence or outbreak of PRRS. This can cause the stress levels and aggressiveness to increase in pigs.
  • Greasy pig or exudative epidermitis. The skin lesion on the tail can lead to other pigs showing interest in the tail area and biting or chewing on it.
  • Diseases involving diarrhoea. Pigs tend be moving around more, the tail is more active, resulting in other pigs attention be drawn to the tail.


  • Light can be a factor, not to dim or too bright. Sixty lux is the recommended level. If light level is too bright and you do have tail biting issues, the pigs will be attracted to the colour of blood.
  • Barns should have a minimum of six hours of darkness a day. It will help reduce the aberrant aggressive behaviour in pigs.

Treating Tail Biting

  • Spray-mark any suspected pigs that are biters and remove if they are the biters
  • Remove or treat any bitten pigs as soon as possible
  • Try to prevent other pigs from being bitten
  • Try anti-biting sprays, if practical
  • Use Stockholm Tar or similar products on tail-bitten area
  • Consult vet about products to reduce infection on tail-bitten pigs
  • Review all issues that could be causing stress or aberrant aggressive behaviour in pigs

Tail biting can be attributed to many factors. Overall you should ensure you are meeting the pig’s biological needs and minimising stress. Try to identify, reduce and react quickly to any issues that can be triggers for tail biting before they occur. Placing ‘pig toys’ in pens may be a help but they must be introduced before tail biting becomes an issue.

Note: The PorkBridge programme is sponsored by the University of Minnesota, South Dakota State University, Iowa State University, University of Nebraska and Ohio State University. The educational series, entitled ‘PorkBridge’, allows pork production owners, managers and employees to increase knowledge and skills in grow-finish production without having to leave the comfort of their home or the farm.

The author has subscribed to the PorkBridge programme for grow-finish operators for the last two years. He comments that it is an excellent programme that addresses current issues in pork production. For more information on the up-coming 2012-2013 session, click here.

July 2012
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