In ADVANTA Yeast 20 the activity of Yeast 20 in the rumen produces metabolites that are used by cellulolytic bacteria, increasing its activity in the degradation of fiber contained in ruminants’ diet. As a facultative anaerobe, Yeast 20 absorbs part of the oxygen present in the rumen, a process that also contributes to the development and activity of fiber degrading bacteria. Yeast 20 offers a third benefit by absorbing small amounts of lactic acid in the rumen, helping to control pH in the rumen.