The most important greenhouse gases from animal agriculture are methane and nitrous oxide. Livestock are responsible for 18 per cent of the greenhouse gases that cause global warming, more than cars, planes and all other forms of transport put … That’s a lot of gas. While the Greenhouse Effect is a natural phenomenon, human activity has increased the levels of some GHG well above historic levels, causing a significant warming trend on a global basis. United States Environmental Protection Agency. Cows and other ruminants account for just 4 percent of all greenhouse gases produced in the United States, he said, and beef cattle just 2 percent of direct emissions. Close. The gases involved in this are called the "Greenhouse Gases" (GHG). "Key facts and findings. Impact of Livestock on Climate Change. Better breeding, genetics and nutrition have increased the efficiency of livestock production in the U.S. The main agricultural greenhouse gases (GHG) are methane and nitrous oxide. (New) "Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2015". Better breeding, genetics and nutrition have increased the efficiency of livestock production in the U.S. The objectives of this manuscript are to 1) discuss the main greenhouse gas emissions sources from the livestock sector and 2) summarize the best mitigation strategies. FAO. By the numbers: GHG emissions by livestock". From burping cows and food miles to greenhouse gases. United States Environmental Protection Agency (new) Cows produce 150 billion gallons of methane per day. Methane is produced in the rumen of the cows by methanogen microbes and are naturally present in all ruminant animals. [xi] Ross, Phillip. "Overview of Greenhouse Gases". In the 1970s, 140 million head of cattle were needed to meet demand. Cows produce between 250 and 500 liters of methane every day. In the 1970s, 140 million head of cattle were needed to meet demand. Cows and other ruminants account for just 4 percent of all greenhouse gases produced in the United States, he said, and beef cattle just 2 percent of direct emissions.