A:   I cannot say with any certainty what is wrong with this cow. That said, if I was the veterinarian driving out to look at her, I'd be wondering on the way if she had an injury causing a lot of swelling in her neck/throat area. The injury might cause the drooling if it affect her ability to swallow, and the resulting inflammation could cause fluid accumulation that would settle, with gravity, to her brisket. An injury like this could come from something she chocked on (like a sharp stick), or could be due to an injury with a balling gun, or a misplaced intravenous injection.

There are many other possibilities. We see swelling of the brisket with problems related to the heart (for example, high altitude disease or hardware disease) or blood (low blood protein, or anemia).