The role of livestock production in global climate change is one of those topics that gets mocked mercilessly by climate change skeptics and TV comedians. Go ahead, insert your favorite cow fart joke here. I’ll wait…

But it isn’t really a laughing matter. According to a 2006 report by the UN’s Food and Agriculture Organization, livestock production is a major source of many of our most pressing environmental problems. The report estimates that, all things considered, livestock are responsible for 18% of current greenhouse gas emissions. With the increase of demand for beef in the developing world – meat consumption is estimated to double in the next twenty years – it is a problem that is going to get worse without some major global changes.

There are a number of ways to deal with the impact of livestock on the environment – changes in agricultural practices, commercial and political pressure from consumers, lifestyle changes – but the agricultural industry and consumer opinion are likely to change course pretty slowly, kind of like turning a cruise ship. While we wait for big Agra to develop a conscience and consumers to eat less beef, scientists have taken the initiative and begun to work on ways to clean up cattle production. A recent article in Nature Reports Climate Change describes the approach that a number of scientists are taking – building a greener cow.

Most of the environmental problems caused by livestock production are a result of raising the cattle – clearing the land required, fertilizer for their feed, transport, and so on. But a mature cow produces a fair amount of the greenhouse gas methane. Cows can not breakdown the cellulose that they consume in plant material and rely on a virtual zoo of microorganisms in their stomachs to help them ferment their food and get some nutritional value from it. One of the byproducts of this fermentation process is hydrogen.

Excess hydrogen in the gut causes problems of its own, so cows usually carry along some microbes to take care of that as well.  Methanogens are a type of microorganism that uses the excess hydrogen as an energy source and produces methane as a waste product. All that methane builds up in the cow’s tummy until it is released – one way or another. Therein lies the problem – this fermentation process in the stomach of cattle is responsible for an estimated 37% of anthropogenic (‘man’-made) methane emissions. Researchers from all over the world are using genomics technologies to try to clear this cloud of cattle pollution.

Scientists from Georgetown and Baylor Universities in the United States and Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) recently published the complete sequence of the cow genome. This effort was not directly related to the issue of reducing animal emissions, but offers researchers a wealth of information about potential genetic targets for designing a cow with a lower environmental impact. A bovine Prius, if you will.

For example, University of Alberta geneticist Stephen Moore has been working to breed cows that require less food and thus produce less waste. Moore uses a technique called association mapping to generate a correlation between a trait (cows that eat less) and genetic markers that may be associated with particular genes. The sequencing of the cow genome offers Moore a much more complete map with which to work. With enough genetic markers, Moore and others can begin to select cattle that are leaner and cleaner.

A group of scientists in New Zealand is homing in on the more specific problem, the methanogens themselves. They recently completed sequencing the genome of Methanobrevibacter ruminantium, a methanogen commonly found in the gut of sheep and cows. With this sequence in hand, the group hopes to find genes that are unique to these organisms that could serve as targets for antibiotics. Remove the source of methane, remove the source of emissions.

Unfortunately, mammalian metabolism isn’t quite so simple. If scientists could get rid of methanogens, something would have to fill the biological role they play – sucking up all that excess hydrogen. And these efforts don’t even touch on the emissions that are associated with the rest of the process, from clearing land to transporting the processed meat and dairy products. There is always more work to do.

That being said, these scientists and many others are taking the proverbial bull by the horns to try and wrestle down the amount of greenhouse gasses emitted in the production of livestock. So, while public and industrial perceptions begin their glacial 180 degree turn, scientists are toiling away to do what they do best – improve our quality of life.

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