This is the abnormal accumulation of clear oedema fluid under the skin of the lower jaw. It can be caused by an increase in local hydrostatic pressure such as from abscessed submandibular lymph nodes blocking lymph drainage or grass seeds blocking salivary ducts. Most commonly it is caused by reduced oncotic pressure as a result of systemic anaemia and hypoproteinaemia.
It is a feature of a number of diseases including chronic liver fluke, gastrointestinal parasitism, malnutrition, congestive heart failure, Johne's disease, woody tongue and abscesses of the lymph nodes of the head and neck.
The severest bottle jaw is seen in chronic liver fluke infections and haemonchosis (barbers pole worm) because these parasites feed on blood. Usually in Australia, chronic liver fluke is seen in the winter and spring, while haemonchosis is seen in summer and autumn. Milder cases of bottle jaw are seen with other internal parasites and Johne's disease where protein is lost from the body through the chronically inflamed bowel wall. It may also be seen with low protein diets. Bottle jaw is most likely to be observed in animals entering assembly points.
Bottle jaw presents as cool, pendulous, pitting swelling under the jaw. With internal parasites and Johne's disease there are usually multiple animals affected and there will be illthrift and diarrhoea. The oedema is generalised in the body but is most obvious under the lower jaw in grazing animals because gravity pulls the fluid into the loose tissue while animals have their heads down eating.
If haemonchosis or liver fluke are present there will also be profound anaemia evident as pale to white mucous membranes of the mouth and eye, exercise intolerance, and dark, dry faeces. At necropsy, liver fluke are found in the liver, and haemonchus worms are found in the abomasum (the fourth stomach).
Blockage of salivary ducts or lymph drainage from abscessed lymph nodes is likely to be sporadic and diagnosed by palpation and close examination for asymmetry.
Low protein in the diet is diagnosed by nutritional evaluation of the feed and exclusion of other causes.
Internal parasite burdens including liver fluke will need to be removed by effective anthelmintics such as macrocyclic lactones, and flukicides such as triclabendazole. Johne's disease is untreatable. Lymph node abscesses are best left untreated. Salivary gland blockages may be treated by massaging and removing any grass seeds found in the opening of a salivary duct under the tongue or in the cheek.
Once the underlying cause is determined, known risk factors should be removed to prevent recurrence.
Bovine ephemeral fever (see Ephemeral fever)