Cows and sheep produce not only milk and cheese: they also produce the greenhouse gas methane.
Swiss scientists have turned their attention to the problem, and are investigating the possibility of modifying the animals’ diet to stop them producing so much gas.
The release of methane into the atmosphere is a major problem. According to the UN Food and Agriculture Organisation (FAO), farm animals are responsible for 18 per cent of total greenhouse gas emissions.
The Federal Agriculture Office says that 80 per cent of methane emissions in Switzerland come from agriculture, largely produced by ruminants - mainly dairy cows - when they chew the cud.
Michael Kreuzer of the Institute of Animal Sciences of the Federal Institute of Technology Zurich (ETHZ) says it is a natural phenomenon.
“Today we have many more ruminants than in the past, and that is the problem.”
Based on the findings of studies indicating that certain plants are capable of neutralising the microorganisms responsible for producing methane during the digestion process, Kreuzer and his research team have experimented with adding natural supplements to the cows’ fodder.
Tannins and flax seeds
After they added powdered tannins to hay, methane emissions dropped by 30 to 40 per cent. The fruit of the soapberry, a shrub native to the Americas, and flax seeds also had a positive impact.
The researchers have also come to the conclusion that crushed flax seeds improve milk quality by adding Omega-3 fatty acids.
Nevertheless, the research has not yet come up with the perfect diet. Agents which neutralise methane could also affect the ruminants’ digestive capability.
“Everything depends on the dosage: if you add too many neutralisers, there’s a danger that the microorganisms responsible for digesting the cellulose could be killed,” researcher Carla Soliva told swissinfo.ch.
“We are now analysing the effect of the tannins on the quality of the meat and the milk production. But at this stage we can rule out any negative impact.”
The ETHZ project is due to last three years. It is part of Switzerland’s contribution to the world-wide search for ways to limit the impact of agriculture on the climate and environment.
Switzerland belongs to a 28-member international alliance created at the time of the 2009 climate conference in Copenhagen with the aim of finding ways of reducing the greenhouse gas emissions produced by agriculture.
“The group is still assessing its procedures, but some priorities have already been established,” Daniel Felder, head of climate strategy at the Agriculture Office, told swissinfo.ch “They include stockbreeding, a sector where Switzerland wants to make a contribution.”
Some countries, including Australia and New Zealand, are working on vaccines to block the bacteria responsible for methane production, he explained.
“This proposal is too drastic and would be difficult to implement in Switzerland. The idea of adding nutritional supplements to fodder, as Professor Kreuzer is now trying to do, seems to me to be more realistic.”
But if cows and goats really represent a risk to the climate, why not apply the “polluter pays” principle?
“Introducing taxes on agriculture would be something new in Switzerland. The first thing is to ask who is to pay, the producer or consumer? And should emissions of greenhouse gases, nitrogen and ammonia be taxed? Those are questions which have not yet been answered,” said Felder.
“Scientific knowledge about greenhouse gas emissions from agriculture is still limited. So at the moment it is hard to suggest ways of reducing them. In any case, targets for agricultural emissions have not yet been fixed at international negotiations.”
But sooner or later discussions will indeed focus on agriculture. To speed things up, the Agriculture Office is in the process of drawing up a new climate strategy.
“The document will consider all sectors where there is a potential for cutting emissions,” Felder promised.
Luigi Jorio, swissinfo.ch (adapted by Julia Slater)
Problems of livestock
Current methods of producing and consuming animal-origin projects are one of the major causes of pollution and global warming, according to a June 2010 report by the UN Environment Programme (UNEP).
Livestock farming requires a lot of water and produces greenhouse gas emissions (in particular CO2 and methane).
Farm animals are also responsible for most ammonia emissions, which contribute to the acidification of ecosystems.
The UNEP report suggested that people should therefore eat less meat and dairy products and switch to a vegetable-rich diet.
But some Finnish researchers have concluded that even if everyone in the world became vegan, eating no animal products at all, this would not solve the problem.
They say that rather than alter food habits, it would be better to change production methods by reducing waste.