A probiotic is defined as “live-organisms which, when consumed in adequate amounts, confer a health effect on the host.” There are two general classes of probiotics: fungi and bacteria. Fungal probiotics are primarily live yeast. Probiotic yeasts work within the rumen to improve fermentation, scavenge oxygen, stabilize rumen pH, improve fiber digestion, and increase microbial growth. Probiotic yeasts remove oxygen (scavenge oxygen) from the rumen and provide a better anaerobic environment for bacterial growth. The anaerobic environment helps in the protection of rumen bacteria from damage …