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Full steam ahead for cows!
2/8/13

vachesnourritureIt is in this context that the recent work from the Department of Agronomical Sciences at Gembloux Agro-Bio Tech - University of Liège (Animal Production Science Unit: Hélène Soyeurt and Nicolas Gengler) and the 'Valorisation of Agricultural Products' Department (Agricultural Product Technology Unit: Frédéric Dehareng and Amélie Vanlierde) and 'Production and Sectors' (Animal Nutrition and Sustainability Unit: Eric Froidmont) at the Walloon Agricultural Research Centre (CRA-W) can be found. Globally, no one is able today to precisely identify the races of cows which emit the most methane, because individual variability between the animals is significant, depending on a number of criteria, such as the type of pasture. It is also known that Animal A and Animal B from the same race and subject to the same diet, may emit different quantities of methane. And this is not insignificant: it can be up to 60%! Evaluating the methane emitted by a cow does not, in itself, pose a problem. Experts currently use two proven methods. The first involves confining the animal in a breathing chamber (all incoming and outgoing flows - including methane - are thus quantified), the other uses a trace gas - sulphur hexafluoride (SF6) - via a little capsule placed in the rumen. However, these techniques are complex and onerous to conduct if they have to be carried out on a large number of animals.

What the Gembloux teams have done is to use a new infra-red tool - an equation - which can be used on living lactating animals in normal conditions (alternating between field/barn), on a regional scale, or even on a farm scale (animal by animal) and using significant databases. The methodological basis of this new tool is mid-infra-red spectrometry (MID). In practical terms: when coming into contact with an infra-red ray, milk reveals a basic spectrum of biomolecules which make it up: fat, protein, minerals, urea, etc. 'Earlier studies have shown that the more short-chain fatty acids contained in the milk, the more methane the animal emits' explain the Gembloux researchers. 'We already knew from our earlier work, that MIR enabled fatty acids to be measured (Read The Mysteries Contained in a Drop of Milk). Since 2007, this measurement has been routinely practised in nearly one farm in three in Wallonia, in the context of milk control. This amounts to more than 100,000 animals, which in quantitative terms is significant. We therefore thought - and it has now been proven - that it would be possible to use the huge database provided by this spectral analysis being carried out for milk control, to predict the methane emissions of a large number of dairy cows in our region.' The major advance, recommended only recently by the researchers, consists of using all milk spectral information and not only that relating to fatty acids, to more accurately and reliably measure methane emissions.

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