The spectrum database includes, in the Walloon region, nearly 2.5 million pieces of information and has the advantage of being updated every month. This is the added bonus of this method! Moreover, it is more interesting than information relating to animals who are no longer productive. In the future we may, therefore, be able to check what characteristics of the milk of an animal are transmitted - or not - to her offspring. At a time when cattle rearing is being globalised (reproductive bulls in our regions may come from anywhere in the world), traditional methods could never have resulted in this level of precision. 'Technically, infra-red spectrometry is less reliable than the breathing chamber or using a trace gas', add the Gembloux researchers. 'But this weakness is largely compensated by the scale of the database available. This enables us, among other things, to use our methane equation to evaluate the effect of food and genetics, with a view to eventually helping farmers to implement the best practices possible in their farms.'

Carbon labelling of foods

The discovery of this method comes at a strategic moment in time. European authorities are currently trying to define a harmonised methodology of quantifying methane emissions. In this context, it is interesting for the Gembloux researchers to upscale their equation, i.e. to be able to apply it to as big a reference population as possible. 'Although the reliability of our method has been established, and at an acceptable cost in practice (20 euro cents per analysis), it remains to be shown that it is robust and that it can be used throughout Europe, or beyond, and that it can be applied to all types of races of cows. Fruitful relationships have been built in this regard with Irish research centres and through international networks such as the Animal Selection, Genetics and Genomics Network. This step, which is more crucial than European legislation on carbon labelling of foodstuffs, is making great progress. In the context of carbon labelling, it may appear inequitable for some farmers to see their dairy production fail to receive a positive label because they have failed to be identified as low emitters using a sufficiently refined and individual method. '

However, indiscriminate application of the equation as a means of wiping the environmental slate clean is not necessarily a step which the Gembloux researchers wish to take. 'If we look the problem through the microscope, i.e. reduction of methane at all costs, we risk embarking on a wild goose chase'. While some interest groups, for example, extol the use of cow foodstuffs based on concentrated feeds, to the detriment of pasture, this would significantly reduce the production of methane per kilo of milk, by, effectively intensifying production. But this would undoubtedly lead to increased emissions of nitrogen from the waste products of farming which, through the action of bacterial populations on the ground, contribute to the release of nitrogen protoxide, a gas which is ten times more warming than methane! Above all, it is important to take into account the life-cycles of various different elements and their respective balances. While grass encourages fermentation in the rumen (and hence the production of methane), grassy fields themselves are primarily non-negligible carbon sinks and use those areas which would otherwise provide only very limited cash crops, in particularly in Ardennes. A ruminant's role is to eat grass and ... to ruminate. Feeding them with corn, on the pretext that this plant causes less methane production, would be nothing more than an ecological absurdity, from the point of view of the impact such farming methods would have on the environment. Moreover, this would be unsustainable in a world which is rapidly approaching 10 billion people. A useful point to bear in mind, in this context of multiple crises (climate, energy, price of foodstuffs, etc.) ...