Live yeast is indeed helpful to regulate rumen microflora and increase milk production. But not all live yeasts show the same effect. Some live yeast can not even survive in the rumen. Only special yeast as YeaVita R screened can regulate rumen health and improve milk production. YeaVita R is a special yeast strain selected from rumen for improving feed digestibility, regulating rumen health and improving ruminant production performance.