Cows in glass tanks help to reduce methane emissions

Of the greenhouse gases produced by humans, 16 per cent consists of methane, of which one third originates in cattle production: more than one billion cattle graze the planet, and each of them emit around 500 litres of methane every day, thereby warming up the climate.

Could it be possible to produce a cow with lower methane emissions through the means available for breeding? The genotype and feed affect a cow's microbial make-up and functioning. Microbes in the cow's intestine and rumen on their part play a key role in the functioning of the cow's entire biological system. "A similar interaction was previously detected in humans," says Johanna Vilkki, professor at Luke.

As part of a project named RuminOmics, led by the University of Aberdeen and funded by the EU, the Natural Resources Institute Finland, in collaboration with ten other European research institutes, investigated the interaction between a ruminant's genotype, feed, and the microbial make-up of the rumen, examining the role these factors played in the energy-efficiency of dairy cattle and their methane emissions.

­Significant differences in methane production between individuals

Under the RuminOmics project, one thousand cows were examined in different European countries. One hundred Ayshire cows visited a metabolic chamber, located in Luke's Jokioinen cowshed, in which their methane emissions were measured. In addition, their digestion, production characteristics, energy-efficiency and metabolism, as well as their microbial make-up, were monitored.

Substantial differences in measurement results were found between different farms and countries, as feeding practices, for example, differ from each other a great deal. It was expected that Finnish and Swedish cows would produce more methane than cows in other countries. This is attributable to their feed which is dominated by silage, not by the climate.

"If the methane emissions from cows are to be reduced, a straightforward approach according to which only cows with low emissions are left in the livestock is perhaps not the best solution. On the contrary, the results indicate that many cows with low methane emissions are inefficient due to the fact that they are unable to make use contained in fodder.

Relative methane emissions of a cow per production unit, kilo of milk or beef are reduced if the production level or production age are increased.

Therefore, it makes sense, from an ethical and environmental perspective, to favour cows with an excellent production capability and keep them in production for as long as possible," Viikki says by way of recommendation.

Genes reveal a cow with low emission

Information available in the near future will indicate whether or not cows with low emissions and a good production capability can be selected for breeding on the basis of genetic data. The study identified areas in the cow's genotype, the variation of which was linked to the amount of methane produced per kilo of milk produced.

"We will investigate whether these genes affect the variation in the microbial make-up of cows' rumen or other characteristics of cows such as the size of their rumen, production level of capability to use fodder."

Reduced emissions and healthier milk

Cows' fodder contains a great deal of unsaturated fatty acids, but the microbes in the rumen transform them into saturated fatty acids. Therefore, approximately 70 percent of the fats in milk comprises solid fats.

The make-up of fatty acids in the cows studied was measured, and its connection to the microbial make-up of the rumen was examined. Further research will reveal whether a cow's fatty acid make-up indicates the cow's methane emissions.

"By changing the feed of cows, we seek to reduce the proportion of microbes causing methane emissions, the amount of which is also related to the amount of saturated fatty acids in milk. Using this method, we can perhaps also change the nutritional make-up of milk in a healthier direction," Viikki remarks.

More Information

What is a metabolic chamber?

Methane production of dairy cattle is measured in the four metabolic chambers at Luke's experimental cowshed in Minkiö. Animal well-being has been taken into consideration in the planning of the chambers.

In order to create an agreeable environment for the cows in their chambers of 20 cubic metres in volume, they have been placed in the vicinity of other cows in the cowshed. The chambers have a steel framework with transparent polycarbonate walls, allowing the cows to see the other cows in the herd. To ensure safety, the chambers have an emergency exit which will open if the equipment experiences a power outage or the carbon dioxide level reaches too high a value.

In the course of studies, air intake and outflow is measured for the concentration of carbon dioxide, oxygen, methane and hydrogen using a gas analyser. The volume of air flow is measured using a mass flowmeter.

Cows' daily feed consumption and milk production is measured and recorded, and the manure and urine produced is collected. This will enable the analysis of the energy metabolism of dairy cattle in addition to methane measurements.