Background and history

This is a very common yet little recognised condition in the sow. When the jaw is at rest, a proportion of sows (often around 5%) and particularly those housed in confinement, show a malalignment of the jaw to the left or right of centre. In extreme cases this can give the appearance of rhinitis. The condition is associated with a loss in height of the vertical part of the mandible or jaw bone and as a result the jaw swings over from one side to the other. The nose is always straight.

There is another rare condition associated particularly with sows derived from the UK breed of Large White. It appears to result from prolonged feeding of very finely ground meal in narrow troughs which provide difficult access. The upper jaw and nose become shortened and flattened, in some cases to a grotesque degree, and the lower jaw protrudes forward several centimetres beyond the nose. There is no evidence of this condition in gilts but it gets worse with age. This is not atrophic rhinitis.

Clinical signs

The vertical part of the jaw bone grows in height from the cartilage that forms part of the mandibular joint. During early growth constant trauma from bar biting or the use of nipple drinkers interferes with the normal growth.

Occasional bending of the nose is seen where there has been infection of the bone as a result of faulty teeth clipping in early life. Neither condition is of significance.

Piglets

• N/A

Sows

• Misalignment of the lower jaw when at rest.
• The upper jaw and nose become shortened and flattened, in some cases to a grotesque degree.

Weaners and growers

• Occasionally, as in sows.

Diagnosis

This is based on the clinical signs and absence of rhinitis.

Causes

• Constant trauma from bar biting or the use of nipple drinkers.
• Infection of the bone as a result of faulty teeth clipping.
• Prolonged feeding of very finely ground meal in narrow troughs.