Project goal

The film focuses on methane (CH4) emissions_fromruminants, which are frequently discussed in the media as a critical contributor to climate change. The film provides a highly informative overview of the natural processes of ruminant digestion and the measurement of gaseous emissions at the HBLFA Raumberg-Gumpenstein research facilities. It discusses the relatively small contribution of CH4_from enteric fermentation in the rumen and presents the results of a feeding trial aimed at reducing CH4_emissions. The trial concluded that adding lemongrass successfully reduced these emissions.

Why cows are not climate killers!

Thomas Guggenberger¹, Georg Terler¹

Unfortunately, this program is no longer available in the media library.

Over 700,000 cows and their offspring in Austria utilize approximately 1.5 million hectares of agricultural land as a source of fodder, thus shaping the local cultural landscape together with our ancestors. In the less fertile regions of Austria, ruminants use this land as pasture in the summer and are fed hay, grass silage, and corn silage in the winter. All of these basic feedstuffs are the result of photosynthesis by their respective plant communities. They provide the animals with energy in the form of glucose and protein in the form of simple nitrogen compounds. While glucose in the form of starch can be digested very efficiently enzymatically, ruminants absolutely require the assistance of bacteria, fungi, and protozoa to digest fiber carbohydrates. These live in symbiosis with the host animal in the rumen, where they break down the stable chemical compounds of plants (enteric fermentation) to produce substances essential for the host's survival. Substances that are not needed or consumed are excreted immediately or later via various excretory pathways, depending on the metabolic pathway.

How is methane produced in ruminant feed?

One pathway involves gaseous emissions, with large quantities of carbon and oxygen_and being exhaled through the animals' lungs in the form of CO₂. Hydrogen released directly in the rumen, which would be toxic to the animal, is converted into methane gas (CH₄) by a specific group of bacteria_expelledthrough the mouth. The amount of CH₄ produced_is directly proportional to the quantity and quality of feed. We can assume that the emission rate is between 2.0 and 2.2% of the ingested dry feed matter. Based on internationally recognized standards, the official Austrian authority currently reports an annual CH₄ emission load of 164.71 kt for ruminant digestion_. A livestock unit (500 kg live weight) thus emits 114 kg of CH₄ from the rumen per_year .

Classification of methane emissions from ruminants

No one would attach particular importance to this connection if global economic growth over the last 100 years hadn't led to an increase in all potential greenhouse gases (GHG) in the atmosphere, thus triggering global warming. CH4_is also a greenhouse gas and is included in the greenhouse gas balance at 28 times its normal level. It is probably primarily due to the sheer magnitude of this factor that ruminants have been declared climate killers. This cannot be explained rationally, as only 3.4% of global greenhouse gases originate from the enteric fermentation of ruminants. This is less than fossil CH4_thatescapes from the world's oil and gas production sites (4.6%) and less than what is caused by our wastewater treatment plants and landfills (3.6%) as a result of direct consumption. The global ruminant bashing, we unfortunately have to acknowledge, is today a trivialization of individual misinterpretations in many areas. Only one argument stands up to objective scrutiny: As the world's population grows, so does the global herd of livestock, thus becoming an expression of unchecked growth with an uncertain outcome!

The Austrian ruminant herd's enteric emissions, however, are at the same level as in 1890 and, with their CH4_emissions, have long since ceased to contribute to the increase in greenhouse gas concentrations in the atmosphere. Mathematically speaking, this is equivalent to a constant; figuratively speaking, it's like an "airplane that doesn't fly!" As long as we are not yet able to incorporate the entire temporal development of sectors into greenhouse gas accounting, we must grudgingly accept the annual balances in order to repeatedly educate the public about the actual situation: Ruminants are a fundamental component of many economies, and their existence is climate-neutral as long as livestock numbers do not increase. This is the case in Austria.

How can Austrian agriculture contribute to climate protection?

While we in Austria are now certain that we are not part of the problem, we still want to become as much a part of the solution as possible. This is important because, apart from agriculture and forestry, no other sector in this country can act as a sink for the excess carbon in the atmosphere. Regarding the use of fossil fuels, agriculture will follow society's established path. Greenhouse gas emissions from fertilization can be reduced through fertilizer use. Completely eliminating imported feed from other continents will eliminate our responsibility for emissions resulting from land-use changes, and the following approaches can be taken to address the issue of CH4_emissionsfrom ruminants:

• Herd size and feeding are determined based on the feed available on the farm. This form of site-appropriate agriculture emphasizes the importance and utilization of farm-owned land and reduces intensification tendencies based on purchased grain or protein crops for ruminants. This approach can be pursued as long as national security of supply for dairy products and beef can be guaranteed.

• Breeding long-lived animals with high yield potential from forage. This measure reduces the need for replacements and thus, in turn, the herd size. Species-appropriate husbandry promotes animal welfare and supports these goals.

• Use of natural, secondary plant compounds with the potential to reduce CH4_emissions, taking into account the veterinary tolerability of their application.

• Selection of ruminants with lower emission potential.

Implementation of the climate protection strategy

For the comprehensive implementation of this climate protection strategy in ruminant farming, both the national protein strategy and an accompanying market-based concept must be implemented. The former ensures a reasonable amount of essential protein, especially for pigs and poultry, while the latter protects domestic farmers from being driven out of the market by cheap, climate-damaging food imports as a consequence of their efforts. Even if the global economy doesn't like to hear it: poor production standards inevitably lead to an international price premium. The extent of any punitive taxes must be comprehensively assessed using life cycle assessment. This significant task is the most important mandate that agriculture has for climate policy in Austria and Europe.

¹ Institute for Farm Animal Research of the HBLFA Raumberg-Gumpenstein, 8952 Irdning-Donnersbachtal

partner

We would like to thank Bilderfest GmbH, especially Rosmarie Bundz, for the detailed and easily understandable presentation of this complex topic!

 

Themed downloads 

Methane emissions from Austrian dairy cows: How significant is the influence of genotype and concentrate feed level?

Five questions on the assessment of agricultural greenhouse gas emissions in Austria