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Vice (abnormal behaviour and vulval biting)

Background and history

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. During the process of damage there can be severe haemorrhage with loss of life in a few animals.

Clinical signs

The vulva is a highly vascular tissue and trauma results in haemorrhage which further attracts sows. Extensive lacerations are common and evidence of blood on the skin and noses of the sows must highlight the possibility of the condition. Severely traumatised vulva heal with scar tissue and this can cause constrictions and difficulties at farrowing.

Sows

Acute

  • Blood on the noses of sows.
  • Blood around the vulva of the affected sow.
  • Haemorrhage.
  • Swollen red torn infected vulva.
  • Occasionally inappetence.

Chronic

  • Scar tissue.
  • Abscesses.
  • Low grade infections.
  • Ascending womb infections discharges.
  • Repeats in some badly affected sows.

Piglets, weaners and growers

  • N/A

Diagnosis

This is obvious from the clinical evidence but an examination should be carried out to ensure the haemorrhage is not arising for the vagina, womb or bladder.

Causes

  • Group behavioural abnormalities.
  • Vulval biting is much more common in pens that are long and narrow rather than those that are wide. There is less competition at feeding time in a wide pen.
  • Vulva biting is also common when electronic feeder systems are used. It requires careful stockmanship and good pen design to prevent it.
  • There is a relationship between vulva biting and feed intake, the size of the feed pellet, the type of floor surface and the bedding used. Many cases occur in the last 3 - 4 weeks of pregnancy.
  • High stocking densities predispose.

Prevention

  • It usually occurs towards the end of pregnancy. The reasons for this are unknown but may be associated with the increased demand for food and perhaps the swollen vulva becomes attractive.
  • Increase the feed intake and assess the response.
  • Increase the salt levels to 0.9% per tonne.
  • It is more likely to occur if the stocking density is high. Allow a minimum of 2.7m2 per sow particularly in the latter part of pregnancy.
  • There is usually one offending sow in the group. If she can be identified remove her.
  • Where floor feeding is practised and the feed is placed in small areas sows group together to feed. Any sow that is excluded quickly learns a simple way to get in is to bite a vulva. To prevent vulval biting therefore it is important to spread the feed as widely as possible over the floor area, even to the extent that where automatic drop or dump feeders are used spread some feed manually as well over the feeding area.
  • Vulva biting is also common when electronic feeder systems are used. It requires careful stockmanship and good pen design to prevent it occurring during the waiting periods outside the feeders and as sows leave them.
  • There is a relationship between feed intake, the size of the feed pellet, the type of floor surface and the bedding used. A change from a small to a larger pellet or vice versa will often improve the situation because it allows a better feeding system on the floor surface. This needs to be carried out by trial and error.
  • Vulval biting is much more common in pens that are long and narrow rather than those that are wide. There is less competition at feeding time in a wide pen.
  • Where there are severe problems within a group move them to a different type of pen with more floor area. Sometimes this will solve the problem, particularly in the last 4 weeks of pregnancy.

Treatment

  • Because sows continue to traumatise an already damaged vulva it is most important that affected sows are removed from the group at the onset.
  • In most cases once the sow is isolated the haemorrhage will stop and the tissues will shrink and heal.
  • Occasionally it is necessary to stem the haemorrhage. To do this sedate or restrain the sow and apply pressure using bandage as a tourniquet.
  • If haemorrhage continues infiltrate local anaesthetic into the vulva and place two or more mattress sutures behind the bleeding points.