Abstract: A method for treating silage to enhance aerobic stability by inhibiting growth of yeast strains associated with spoilage of silage is disclosed. The method comprises treating silage or feed with a composition comprising killer yeast strains, or the antimicrobial components produced thereby. According to the invention, strains of Saccharomyces exiguus have been purified and isolated which are nontoxic, safe, do not assimilate lactate and which improve aerobic stability of silage, are disclosed. Portions of these strains have been sequenced to further characterize the invention.