We have notices a corolation with fox tail and also barley green feed with barley awns. They poke inside the mouth area and if you do not catch it reall quick and early by flushing out the mouth and working in the mouth like a dentist, lumpy jaw is sure to happen.
Iodine IV works if you catch it real quick and early before the bone becomes honeycomb. Might need two treatments. We are also iodine defficient here so we put extra iodine in the mineral every so often. we follow the vet's recommendations. It has helped alot.
As well, once lumpy jaw breaks or absesses, you are putting the rest of the herd at risk. This is from experience and picking our vets brain. we do that alot.
What happens is, the bacteria is in the jaw contained. Once the sores break open either in the mouth or outside the mouth, the bactereia is shed. The cow sheds it in the hay or gain by drooling and the pus on the feed. She also sheds it in the water trough.
If an animal has a sore in it's mouth and feeds in the same area or drinks from the same fount, the bacteria enters the mouth and voila, another case.
The bacteria is naturally occuring in the cattle, but somehow once it enters the mouth and absesses, it doesn't mutate, but changes, and can then infect other cattle.
Word of advice from someone who has treated several, if treatment does not work, confine, keep away from others, and ship or rail grade, or euthanize.
We kept a few, "oh they raise a good calf" " wait until they wean" and we just got more cases. Once we cleared them out of the herd and used iodine as an aditive (must be careful not to od) we have not had another case. Hope the luch holds out.