Like all ruminants, cows play a significant role in the production of greenhouse gases, particularly methane. Genetic selection and foodstuffs can, of course, reduce this negative impact. But what is needed is a reliable method which is financially accessible both to farmers and the dairy industry, as well as which can be rolled out on a very large scale. A decisive step towards this has just been accomplished by researchers at Gembloux Agro-Bio Tech in partnership with the CRA-W. They have used information provided from the infra-red analysis of cows' milk to precisely and reliably estimate methane emissions. This step, which is even more crucial than European legislation on carbon labelling of foodstuffs, is making great progress.
In rural areas all over the world, it is stating the obvious to say that cows fart and burp. Something which gives rise to a panoply of schoolboy jokes however, becomes a much more serious reality if we look at the bigger picture. This daily activity of our cows, which are fundamentally and necessarily ruminants, represents a significant contribution to the concentration of greenhouse gases in the atmosphere. Among these gases is methane, which, as is now universally known, has increased substantially over the past 150 years. Methane (CH4) is produced in a cow's rumen, a complex 'pocket' which is situated upstream of the stomach, and results from the decomposition of cellulose from the plants upon which the animal is grazing. Ruminants therefore emit methane through their mouths during periods of rumination, rather than with their excrement as is often imagined.
The contribution of methane from cows to global warming is not negligible. Initially because, even although it remains in the atmosphere 8-10 times less than carbon dioxide (CO2), CH4 develops a warming potential which is some 23-25 times higher than CO2. And our planet is home to nearly 1.3 billion cows. Although cows are far from being the only domestic animal which contribute to the emission of methane, their number is likely to rise in the coming decades under the effect of demographic growth. Currently, according to the Food and Agriculture Organisation (FAO), cattle rearing alone contributes to 4.5% of global warming. Even although the Western world will soon have to revert to less meat consumption, cows are unlikely to be rendered obsolete at any time in the near future: as sources of milk, leather and gelatine, etc. without overlooking their pulling power in some countries and their sacredness in India.
500 grams of methane per day
In our regions, enteric fermentation (i.e. the microbial decomposition of food in the rumen) leads to the emission of 400 to 500 grams of methane per cow per day. Much as transport and domestic heating, there is no reason why cattle rearing should not also contribute towards the global drive to reducing greenhouse gas emissions. This new mission involves work both on genetics and foodstuffs, seeking to identify stem cells from cows emitting the least methane and adapting foodstuffs to try to reduce this (the ideal is obviously to combine these two avenues wherever possible).