Practical solutions to reduce greenhouse gases from livestock farming

Around 10 percent of greenhouse gas emissions in the Netherlands come from livestock farming, with methane being the main contributor. Methane is produced while feed is being digested in the gastrointestinal tract of animals and from manure.

The work of WUR in the field of nutrition, genetics and manure focuses on making solutions practical and sharing knowledge for sustainable livestock farming. We do this in conjunction with other sustainability tasks, such as water quality, animal welfare and biodiversity.

The animal’s menu greatly influences the amount of methane an animal produces. In recent years, we have been working hard on practical solutions. For example, we know that with the quality of roughage, with fresh grass straight from the pasture and with additives in food, we can ensure lower methane emissions. 

Download the brochure 'Ten questions ans answers about methane'

Ruminants such as cows and goats can only break down tough grass fibres with bacteria in the rumen. During digestion, methane is released: the animals breathe or burp it out. Our research shows that replacing grass silage with maize with a high starch content reduces methane emissions because starch is easy to digest. For a diet with a quarter of maize as roughage, the reduction is about three to four percent methane compared to a diet with only grass silage as roughage.

Another promising option is fresh grass. Researchers compared methane emissions from cows grazing in pasture or given fresh grass in the barn, with a diet of only grass silage in the barn. It appears that the greatest reduction is with day and night grazing and in spring. Young, fresh grass is highly digestible and has a different composition from grass silage.

Feed additives also significantly reduce methane emissions from dairy cows, depending on the diet and the amount of methane inhibitor added. The additive has no health effects: the synthetic substance 3-NOP breaks down quickly and is converted into natural substances. We are also studying herbs that may stimulate rumen microflora.In the search for the low-emission cow, the focus is not only on feed; researchers also see great opportunities for breeding. We found that there are substantial differences in terms of methane emissions between individual cows and that about 20 percent of these are hereditary. Breeding for this trait can yield a reduction of one percent a year. Towards 2050, this could rise to up to a quarter.

For years, our researchers have been working hard to collect and analyse a huge amount of data. Using self-designed sniffers, they first measured the breath of some 15,000 cows over long periods of time on 100 farms. This enabled us to collect methane emission information from each individual cow. We linked that data to the animals' pedigree data.  This then enabled us to estimate breeding values from which we can deduce how much methane will be emitted on average by the cows’ offspring. Breeding to produce less methane is possible without affecting production and health, for example.

Recently, breeding values were presented to the sector so that livestock farmers can take them into account in their sire selection. Moreover, we are leading a major global project aimed at encouraging the selection of animals producing less methane on almost every continent.

Not only is methane released from the animal's digestive tract, 20 percent of cows' methane emissions come from manure. Experts have already identified several options to reduce those emissions, such as separating the manure, oxidising the methane or simply removing the manure from the barn quickly.