Methane is one of the principal greenhouse gases, second
             only to carbon dioxide (CO2), and with a global warming potential twenty-one times greater. Methane made an
             estimated contribution of 18 percent to the radiative forcing of the climate in 1990. A potential effect of climate
             change includes increased frequency of extreme weather events, such as floods, drought, and severe storms.
             Changes in precipitation and temperature patterns could jeopardize current agricultural practices, and tropical
             diseases and pests could increase their range. In addition, raised sea levels could threaten vulnerable coastlines
             around the world (Environmental Protection Agency).
             Domesticated ruminant (cud-chewing) animals, with an ever-increasing population, constitute the largest
             source of anthropogenic methane emissions. Ruminants, such as cattle, sheep, and goats, have a unique, four-
             chambered stomach. In the large chamber of the stomach called the rumen, microbial fermentation in the animal's
             digestive system breaks down food into soluble products that the animal can utilize. Ruminant animals are unique
             because their special digestive system allows them to convert otherwise unusable plant materials into nutritious
             food and fiber. However, this microbial fermentation process, referred to as enteric fermentation, produces
             methane gas as a by-product, which is exhaled by the animal (Center for International Earth Science Information
             The production rate and amount of methane created is affected by factors such as quality and quantity of
             food, body weight, age, and exercise. Inefficient feed utilization leads to high exhaled methane emissions, and
             ruminants on low quality feeds produce more than 75 percent of the total livestock methane emissions. In many
             emerging market countries, animal diets consist mainly of low quality feed such as rice straw and sugarcane tops
             that lack the daily nutrients necessa...