Widespread concern over global warming has spurred an emerging need to mitigate the release of “Cow Flatulence” which is lost as methane gas. Diet modification through the use of Micro-Aid®, an all-natural, feed additive, is one means to help lessen methane emissions from cattle. This study evaluated the effects of Micro-Aid® and forage type on in vitro methane production. Regardless of the mixture of forage to concentrate in the diet, the supplementation of Micro-Aid® consistently decreased (P < 0.002) the total production of methane at 24 hours.