Sub-acute rumen acidosis (SARA) is a prevalent problem for dairy herds as characterized by having more than 25 percent of cows sampled via rumenocentesis four to eight hours after a total mixed ration (TMR) meal with ruminal pH less than 5.5. Ruminal pH is largely a function of the balance between the production of volatile fatty acids from the fermentation of carbohydrates, their neutralization by salivary and dietary buffers and their removal by absorption across the rumen wall or passage from the rumen, and SARA is caused by the consumption of high amounts of ruminally-available carbohydrate, low amounts of effective fiber or both.