Cows with Gas: India's Global-Warming Problem

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Ed Kashi / Corbis

Cows from Rajastan travel on the Golden Quadrilateral highway to find water and grazing areas

Indolent cows languidly chewing their cud while befuddled motorists honk and maneuver their vehicles around them is an image as stereotypically Indian as saffron-clad holy men and the Taj Mahal. Now, however, India's ubiquitous cows — of which there are 283 million, more than anywhere else in the world — are assuming a more menacing role as they become part of the climate-change debate.

By burping, belching and excreting copious amounts of methane — a greenhouse gas that traps 20 times more heat than carbon dioxide — India's livestock of roughly 485 million (including sheep and goats) contributes more to global warming than the vehicles the animals obstruct. With new research suggesting that methane emission by Indian livestock is higher than previously estimated, scientists are furiously working at designing diets to help bovines and other ruminants eat better, stay more energetic and secrete smaller amounts of the offensive gas. (See pictures of India's largest ruminant: the Asian elephant.)

Last month, scientists at the Space Applications Centre in Ahmedabad in western India published a pan-India livestock methane-emission inventory, the first ever, which put the figure at 11.75 million metric tons per year — higher than the 9 million metric tons estimated in 1994. This amount is likely to increase as higher incomes and consumption rates put pressure on the country's dairy industry to become even more productive. (See pictures of China's cow town.)

Already the world's largest producer of milk, India will have to yank up production from the current 100 million metric tons to 180 million metric tons by 2021-22 to keep pace with growing population and expanding disposable incomes. Livestock such as cows, buffalo, goats, sheep, horses and mules are indispensable to India's rural economy — whether the animals are yoked to plow land, raised for milk and manure or harnessed to pull carts to move goods and people. The Ministry of Agriculture estimates that livestock contribute 5.3% to total GDP, up from 4.8% during 1980-81. But, says K.K. Singhal, head of dairy cattle nutrition at the National Dairy Research Institute in Karnal in northern India, "while livestock plays a crucial role in the economy, global warming is becoming a huge worry. We're trying to find indigenous solutions, because our realities are very different from the West." (See 10 things you should know about the world's cheapest car, India's Nano.)

For starters, most Indian livestock is underfed and undernourished, unlike its robust counterparts in richer countries. The typical Indian farmer is unable to buy expensive dietary supplements even for livestock of productive age, and dry milch cattle and older farm animals are invariably turned out to fend for themselves. Poor-quality feed equals poor animal health as well as higher methane production. Also, even when Western firms are willing to share technology or when Western products are available, these options are often unaffordable for the majority in India. For instance, Monensin, an antibiotic whose slow-release formula reduces methane emission by cows, proved too expensive for widespread use in India. So the emphasis for Indian scientists is on indigenous solutions. "We know we cannot count on high-quality feed and fodder," says Singhal. "No one will be able to afford it. What we have done instead is develop cheaper technologies and products." One example is urea-molasses-mineral blocks that are cheap, reduce methane emission by 20%, and also provide more nutrition, so they're easier to sell to illiterate farmers who don't know a thing about global warming but want higher milk yields.

Most dietary interventions work by checking methogens — microbes that thrive in oxygen-free environments like cows' guts, where they convert the available hydrogen and carbon (by-products of digestion) into methane, a colorless, odorless gas. "We encourage well-to-do farmers to use oilseed cakes, which provide unsaturated fatty acids that get rid of the hydrogen," Singhal says. Another solution is herbal additives. Some commonly used Indian herbs such as shikakai and reetha, which go into making soap, and many kinds of oilseeds contain saponins and tannins, substances that make for lathery, bitter meals but block hydrogen availability for methogens. Singhal says the herbs are used in small quantities and the cows don't seem to mind the taste. "Imagine how much potential they'd have in the international market," he says. (See pictures of India's biodegradable dishware.)

Several other institutions, like the National Institute of Animal Nutrition and Physiology (NIANP) in Bangalore, are also researching herbs. "We're studying the effect of tannin compounds from various easily-available sources like tea leaves. We're also studying prebiotic and probiotic feed supplements," says K.T. Sampath, director of NIANP. Other institutes, like the New Delhi–based Energy Research Institute (TERI), are working on methane-capture strategies. One long-running project has been biogas production — cow dung utilized to make biogas for use in kitchens, and even compressed biogas for use in vehicles. "Biogas plants have been very successful," says R.K. Rajeshwari, a fellow at TERI. "Farmers are able to use biogas in their kitchens, to light lamps and to even drive vehicles." Such projects, she says, have been particularly successful at gaushalas, cow shelters supported by donations from the devout and by government grants, of which there are 4,000 across India. Most gaushalas are for abandoned, dry and aged cattle, of which there are many, since killing cows is illegal in all but two states (the communist-ruled West Bengal and Kerala). "This way they are put to some use at least," says Rajeshwari. "And by replacing conventional sources of energy, they help prevent global warming."

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