Methane reduction linked to better on-farm profitability

Reducing methane production enhances on-farm profitability, according to the preliminary findings of a potentially game-changing international project involving Teagasc, the Irish Cattle Breeding Federation (ICBF) and University College Dublin (UCD).

Earlier today, Friday, January 17, Paul Smith, a third year PhD student at Teagasc Grange presented some initial results from the on-going ‘RumenPredict’ project, which aims to link the rumen microbiome (all bacteria, fungi, etc, that live in the rumen), host genetics and feed efficiency to methane emissions in a bid to benefit mitigation strategies.

Speaking at the ICBF and Sheep Ireland Genetics Conference in Laois, Smith – whose own research on methane emissions from suckler beef makes up part of this larger scale €1.5 million project involving seven member states – gave a flavour of the data emerging to date.

As part of the project, cattle are housed at the ICBF Progeny Test Centre in Tully, Co. Kildare.

There methane output tests are being carried out using a ‘GreenFeed’ machine, which allows researchers to get an accurate reading of methane and carbon dioxide from each animal.

The cattle undergo a 120-day finishing period, with a 30-day acclimatisation period where animals are trained to use the machine. Subsequently, methane emissions are estimated over a three-week period using the machine.

Speaking at the conference at The Heritage Hotel in Killenard, Smith said: “The main objectives of the project are to enhance the understanding of the role of diet, genetics and rumen microbiome on environmental outputs and greenhouse gases.”

To achieve this the project is taking a three-tier approach.

“Firstly, we are identifying cattle by focusing on feed efficiency and methane production; secondly, we are identifying key rumen microbes or ‘bugs’ associated with low methane or high methane; thirdly, at the end of the project we will identify DNA-based markers that are linked to rumen microbiome – which in turn is linked to methane production.

In terms of methane yield, heifers are producing roughly 22.1g of methane per kg of DMI. Steers are producing 22.3g of methane per kg of DMI.

“There is a difference of 0.7%, as naturally steers are heavier and have higher feed intake,” said Smith.

Continuing, he asked: “So, will a reduction in methane production enhance on-farm profitability?

“Based on the data we have generated to date; so far, we’d say a tentative ‘yes’.

“We’re starting to see a negative correlation developing between methane yield – that’s methane produced based on DMI – and the replacement index.

So basically, when methane yield reduces animals tend to have a higher ranking on the replacement index.

“This is a good news story for the sector from the data we have collected so far,” said Smith, adding that similar research is expected to be carried out on sheep.

Mitigation

As part of his presentation, Smith also explained – in detail – the reality of methane production on farms and the challenges posed by global and national policy on climate change.

Agriculture, as he pointed out, faces two major global challenges – the need to produce enough food to feed more than 10 billion people by 2050 – which needs to be achieved from a static land block – plus, there is mounting international pressure on the sector to reduce its carbon footprint.

According to the Food and Agriculture Organisation (FAO) of the United Nations, livestock production is responsible for 14.5% of the world’s greenhouse gas (GHG) emissions.

Under the 2015 Paris Agreement, international governments have committed to limiting global warming to well below 2°C, with the ambition to further reduce it to 1.5°C.

The EU’s carbon emission reduction target for the end of 2020 is to reduce emissions by 30% on 1990 levels; it has also committed to reducing GHG emissions by 40% by the end of 2030.

In order for Ireland to achieve its reduction targets within 2030 timeframe, it means that GHG emissions must decline by more than 2% every year for the next decade.

“Plus, there is the ambition from a national level to be carbon neutral by the year 2050,” said Smith.

With more than a third of Ireland’s GHG emissions arising from agriculture (34%), the main source of Ireland’s agriculture GHG emissions is enteric fermentation – in other words, as Smith explained, the process carried out in the rumen of cattle and sheep where methane (CH4) and carbon dioxide (CO2) are produced.

What is methane?

Methane is the second most important greenhouse gas in relation to global warming.

It is about 28 times more powerful than carbon dioxide at warming the environment and has an atmospheric life of about 12 years – until it is broken down into carbon dioxide.

Ruminant animals are responsible for around 30% of global methane emissions, Smith underlined.

The whole process of methane production within the ruminant actually acts as an energy loss, so roughly 2% to 12% of the energy that the animal consumes is lost as methane when emitted from the animal.

“As the animal ingests grass or cereals it goes into the ruminent.

“Microbes in the ruminent produce enzymes to actively break this down and through that process they produce ‘fermentation end products’ – which are hydrogen and carbon dioxide.

“Basically hydrogen needs to be expelled from the rumen – these are an additional set of microbes known as ‘methanogens’ – as a way relieving that pressure and preventing it from building up,” said Smith.

How to measure methane output?

The presentation explained that currently there are three main methane measurement techniques in research.

These are: the ‘respiration chamber’; the ‘SF6’ method (akin to a jetpack on the back of cattle); and the ‘GreenFeed System’.

When it comes to reporting methane output it can be reported in three ways too. These are: daily methane output (CH4 g / day); methane yield (CH4 g / kg of DMI); and methane intensity (CH4 g / kg of carcass weight).

According to Smith, when it comes to methane production more than 70% of the variation within animals directly corresponds to daily feed intake.

From a sectoral point of view, he said methane intensity essentially correlates to the amount of methane produced per kg of carcass weight or per litre of milk produced in a dairy context.

Beef strategies

The current methane mitigation strategies in place for Irish beef were listed at during the presentation.

“Firstly, there is a reduction in livestock numbers – but, let’s be honest, nobody wants to do that.

“Next, is the dietary route. Certain studies have shown that certain supplements (e.g. lipids and oils or synthetic compounds) can be added to the animals diet and can be shown to reduce methane.

“There is actually a project starting soon in Teagasc that is going to test a few of these novel supplementary additives.

Improvements can also be made through pasture quality as studies have shown that animals raised on higher-quality pastures produce less methane compared to animals grazing on lesser-quality pasture.

“Another strategy is to go down the ‘animal selection’ route, whereby animals can be identified and selected with reduced methanogenic potential – in other words, selecting animals from breeds that produce less methane,” he said.

It was also stated that animals can also be selected for increased feed efficiency, as studies have shown that animals that are more feed efficient produce less methane.

Smith highlighted that gains made on the genetics front would be considered a strategy focused on permanent and accumulative benefits.

“To go down the animal selection route we need a better understanding of the biology associated with methane production – particularly the microbiology involved in what’s happening in the rumen to have a greater understanding of composition between high and low methane emitting animals,” he said.

The three-year RumenPredict project is due to end in September 2020.

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