The subject invention provides compositions and methods for reducing deleterious atmospheric gases and/or precursors thereof using livestock feed additives and/or supplements. In preferred embodiments, a multi-purpose composition comprising one or more beneficial microorganisms and/or one or more microbial growth by-products is applied to livestock animals' feed and/or to a field or pasture where livestock animals graze. In some embodiments, the composition controls methanogenic bacteria. In some embodiments, the composition enhances carbon sequestration in the field or pasture by promoting plant health and/or growth.
