Actionomycosis - Bony Lump Jaw in Cattle

by Heather Smith Thomas

Bacteria are often present in the mouth of cattle, so anything that punctures the mouth tissues may open the way for infection, possibly leading to "lump jaw." According to Dr. Robert Cope, veterinarian at Salmon, Idaho, there are two kinds of "lump jaw," caused by two types of bacteria, that require different treatment.

Most common are soft tissue infections that are relatively easy to treat by lancing and draining. Another type of lump is caused by infection in the bone, and it is difficult to halt, says Cope. It usually results in having to butcher the animal. Bony lump jaw tends to occur most often in young cattle, two or three years of age.

Both types of lump jaw begin in the same manner. A break in the tissue allows bacteria to enter. A sharp seed or sharp object in the feed may poke the side of the mouth. Ulcers caused by BVD virus can open the way for bacteria, which can then enter from feed or soil. Grazing cattle may pull plants up by the roots, eating dirt clinging to the roots. Cattle fed on the ground may pick up dirt or mud eating the feed.

The most common form of lump jaw is caused by a bacteria -- Actinobacillus -- in the soft tissues, forming an abscess along the lower jaw. "Actinobacillus is a Gram-negative bacteria routinely present in the soil in many areas," says Cope. The lump may be hard or soft, but can be moved around if you press it firmly with your hand; it is not attached to the bone.

A different bacteria, Actinomyces bovis (a gram positive bacteria that also lives in soil), can infect the mouth and cause bony lump jaw. The condition is called Actinomycosis. This bacteria enters a wound or dental socket in the mouth the same way, says Cope, but infects the bone if the break in the tissues penetrates deeply.

The infection gets going in the upper or lower jaw, creating a painless bony enlargement, usually at the level of the central molars. In rare cases it involves tissues of mouth and throat if lacerations permit entrance of bacteria. Bony lump jaw occurs only sporadically, but is a serious condition because of poor response to treatment. A general enlargement on the lower jawbone may appear as a thickening of the lower edge of the bone (with most of the enlargement between the two sides of the jaw); these lumps may not be observed until they are quite large and too extensive for treatment to be effective. The more common protrusions on the side of the bone are more easily seen.

The lump on this three-year-old cow began developing six months earlier. It has now broken through the skin

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Some swellings enlarge swiftly in a few weeks, while others grow slowly over several months. The bony swellings are very hard and quite immobile. You can't move the lump around with your hand because it is part of the bone. There is no affect on the animal's health at first; this infection does not create illness. In later stages the area may be painful and interfere with chewing. The lump may break through the skin eventually and discharge through one or more openings, oozing a little pus or some sticky honey-like fluid containing tiny hard yellow granules, says Cope.

Lancing is of no value, since the lump is composed of infected bone and cannot be drained. The oozing area may heal over, only to break out again. "Attempting to drain this lesion is fruitless at best," says Cope, "and can be harmful. Opening this area to the outside may allow other disease organisms to enter, resulting in further secondary infection. When you see an animal with a swollen jaw or lump, feel the jaw and try to move the lump--to tell the two types of diseases apart." A bony lump should never be lanced.
Teeth in the affected jawbone may become misaligned and cause pain when chewing. This makes it hard for the animal to eat and can result in losing weight. In severe cases, the infection spreads to softer tissues and involves the muscles and lining of the throat, interfering with the animal's ability to belch and chew its cud. If swelling becomes extensive, it can interfere with breathing. The animal may become so thin that humane destruction is necessary, though it may take a year to get this bad. If the infection spreads to the esophagus and stomach, digestion becomes impaired, causing diarrhea (passing undigested food particles on through) or bloat.

This cow is receiving sodium iodide intravenously. Some lumps reduce in size, but may not go away completely.

A bony lump is a bone infection, and "must be treated from the inside out, via the bloodstream that serves the bone," says Cope.

Usual treatment is sodium iodide into the jugular vein, repeated in 10 days. Even this treatment is not always successful in halting the bone infection. The lump may stop growing for awhile and you can get a feedlot animal marketed, or you might get one or two more calves from a cow, then it starts again.

Iodides given intravenously may halt the infection if given early (before the lump gets large) but many cases are stubborn, says Cope. Some lumps reduce in size once infection is stopped, but never go away completely. He says abortion may occasionally occur after iodide treatment if a cow is pregnant. "We often try to postpone treatment of bony lump jaw during late pregnancy, hoping to save the cow and calf both. But if the cow is going downhill or not due to calve for some time, we will usually treat the cow and take our chances with the possibility of abortion." ©