Chew and spew

The fact that methane is crucially responsible in heating up the earth's atmosphere is well established, but the lesser-known truth is that the mastication of food by domesticated, ruminants is the second largest source of methane

 
Last Updated: Saturday 04 July 2015

METHANE is the second most important contributor to global warming after chlorofluorocarbons (CFCs), with a 100-year global warming potential (GWP) of 24.5. And domesticated ruminants (cattle and camels), contribute about 20-25 per cent of global methane production annually. Of this, 85 per cent is added to the atmosphere when the animals chew the cud for better digestion (joint Impleme6tion Quarterly, Vol 1, No 3).

Digestion in ruminants involves anaerobic bacterial action, and the process is called enteric fermentation. The organic matter undergoes complete degradation towards the final stages of digestion. The end-products of the process of degradation are methane, carbondioxide and water.

2CH2O + H2O --- CH4 + CO2 + H2O - 58KJ Even though more than 50 per cent of the world's livestock population is to be found in the developing world, these countries contribute less than 15 per cent of the global milk and meat production. Most of these animals do not feed on adequate or good quality fodder, because of which they release higher amounts of methane per unit of meat or milk yielded when compared to their better-fed counterparts elsewhere in the world.

This problem, according to the Environm6ntal Protection Agency (EPA) of the US, can be reduced by better livestock management involving either the improvement of the quality of feed or supplementing it. The EPA estimates that these efforts would help reduce livestock methane emissions by 25-75 per cent in developing countries, thereby reducing global emissions of methane from ruminants by up to 12 per cent. Not only that, but total global methane emissions would also be reduced by about 30 per cent. Better management of domestic ruminants would also increase milk and meat productivity by 20-35 per cent, thus improving the economic conditions of their owners.

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