A popular group of probiotics are the live yeast products, based on Saccharomyces cerevisiae. Adding cultures of live yeast to rations for dairy cattle results in an increased rate of cellulolyses and an increased flow of microbial protein to the small intestine. This results in an increased supply of nutrients like volatile fatty acids and metabolisble protein to the host animal.
This increase in nutrient supply may result in an increased production of milk constituents such as lactose, protein and fat.
In addition, recent data showed that supplementation of live yeast significantly increases the frequency of feed consumption of cows and therefore helps in preventing acidosis (because meal frequency appears to be an important factor in regulating rumen pH).