Yeast and yeast-based products not only alter immune function in animals, but they also possess the
potential to enhance performance and alter metabolism. Thrune et al. [4] reported that dairy cows
supplemented with Saccharomyces cerevisiae displayed less volatile fatty acid (VFA) concentrations
in the rumen compared to control animals, and furthermore, yeast supplementation decreased duration
of acidosis. Wohlt et al. [19] reported increases in dry matter intake (DMI) and milk yield in dairy
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cows in early lactation when supplemented with Saccharomyces cerevisiae. Increases in DMI and gain
have also been reported in beef cattle supplemented with Saccharomyces cerevisiae during the
receiving period [20]. Data from an in vitro study suggests that Saccharomyces cerevisiae supplements
may also affect rumen pH and nutrient digestibility [21]. Yeast supplements affect live performance,
although these supplements have also been reported to influence carcass performance and composition
in growing lambs