This condition is caused by repeated periods of rumen pH reduction (5.2 to 5.6) due to increased levels of production of volatile fatty acids in the rumen. Affected animals show reduced feed intake and milk production, poor body condition with weight loss, and sometimes diarrhea. As with the acute form of the disease, these repeated episodes lead to colicitis, with damage to the epithelium, often accompanied by the development of liver abscesses. The frequent low pH environment also changes the normal flora in the rumen.
Postmortem diagnosis of acute colicitis can be difficult and is best done by microscopic examination of the rumen epithelium. Fungal ruminitis in the post-mortem examination shows relatively significant patches of dark epithelium. Treatment and control of acute rumen acidosis is a disease with high mortality and it is often recommended that affected animals be slaughtered before death. If treatment is desired, it should be very aggressive and include removal of rumen contents through the rumen, intensive fluid therapy to combat dehydration and acidosis.
More acute and severe cases of rumen acidosis are managed by administering bases to neutralize the acid, reducing healthy grains, and randomly placing the animal on long-stem hay. The key practice required to minimize the development of rumen acidosis is to slowly adapt animals to a diet containing high amounts of grain. Some authorities recommend feeding buffer animals such as sodium or potassium bicarbonate, although this practice is unlikely to completely prevent acidosis.