We have dealt with bloat on numerous occaisons. Once a cow goes down with it the chances of saving her are very small. What happens when it gets bad enough is that the bloated rumen puts pressure on the lungs and heart so that the animal eventually suffocates, or it's heart quits.
There are 2 basic kinds of bloat:
Frothy bloat, happens quite often on lush pastures, especially those containing legumes. This can also happen to grain fed animals. It is basically caused by fine, and small particles of feed, which are digested too quickly.
Gassy bloat on the other hand may be caused by an obstruction of the esophogus, illness, or an inhibition of rumen movement. The biggest cause is a sudden change in the diet.
Treatment may include, walking the animal around, passing a tube down the throat to expell gas, and tubing the animal with a surfactent, or mineral oil. In extreme cases, one may need to make an incision in the flank to release the excess gas. Once an animal starts to stagger, or goes down the chance of saving it is virtually non-existent, and making the incision may be the only option at this point.
The following is a very good article on the types of bloat, what causes them, how to prevent, and how to treat. Well worth the read.
[URL="http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex6769[/URL]
http://www2.dpi.qld.gov.au/dairy/7808.html
Here is an animal that we had to puncture in order to save her. She also got a dose of mineral oil at the same time. It is 2 weeks later and she is just fine. The cause was an overly fine and well put up alfalfa hay bale. The incision is about 2 inches in length, and much less traumatizing than death. The spot where the incision was made is the dark area on her left side.
