Genetic Selection

Some cows emit less methane than others, without any drop in yield.
Genetic selection helps farmers breed lower-emission, more efficient dairy herds over time.

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The Climate Issue

Every cow is different. Some eat more feed, some walk more kilometres, and some produce more milk solids per kilogram of intake. That efficiency also affects methane.

On average, two cows eating the same diet can emit different levels of greenhouse gases. Less efficient cows produce more methane and waste more energy per litre of milk. These small differences, multiplied across a herd, shape the farm’s carbon footprint.

Yet for years, breeding decisions were made mostly on yield and fertility. Emissions weren’t measured – and low-emission cows were not prioritised. That’s now changing.

The Solution: Genetic Selection

Genetic selection identifies and promotes traits that reduce emissions intensity, especially methane per kg of milk. This is done by including environmental data, feed efficiency, and methane metrics into breeding indexes.

In Ireland, the Economic Breeding Index (EBI) is already helping. Cows with high EBI scores typically produce more milk solids, calve earlier, and stay healthier. Now, low-methane traits are being added to improve environmental efficiency.

Over time, selecting bulls and cows with better feed conversion and lower emissions will reshape herd performance. These changes are permanent, cumulative, and low-cost.

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Key Benefits with Genetic Selection

Lower Emissions

Each new generation emits slightly less methane per kg milk. That adds up over years – helping farms hit targets without changing feed or housing.

Lifetime Efficiency

Less nitrogen lost means more available for crops. Protected Urea helps you get more from every kilogram applied, improving yields and reducing input needs over time.

No Extra Cost

Genetic improvement comes with no additional daily costs. It builds into your existing breeding plan and delivers both performance and climate benefits.

Impact of doing Genetic Selection

Genetic selection is a slow but powerful tool. When built into breeding plans, it steadily reduces emissions without affecting productivity or daily operations.

Teagasc and ICBF models show that using high-EBI, low-emission genetics can:

Cut enteric methane by 10–15 % over 10 years
Improve feed conversion by 2–4 %
Reduce GHG per litre of milk by 0.03–0.06 kg CO₂-eq
Deliver €50–€90/year more per cow in performance gains

See the impact below based on genetic adoption scenarios over a 5-year window. We use the Irish EBI as an example for scenarios.

Scenario	Genetic Focus	Net Gains / 100 cows	GHG Emissions	% GHG Reduction
Low Genetic Focus	€135 EBI	-	0.960 kg CO₂-eq/kg milk	0% kg CO₂-eq/kg milk
Medium Genetic Focus	€175 EBI	€3, 500	0.934 kg CO₂-eq/kg milk	2.7% kg CO₂-eq/kg milk
High Genetic Focus	€210+ EBI + CH₄ Index	€7 ,800	0.900 kg CO₂-eq/kg milk	6.3% kg CO₂-eq/kg milk

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Considerations

Long Term Strategy

Genetic gains are not instant. It takes several years and consistent breeding to see a measurable drop in emissions. But once achieved, gains are permanent and cumulative.

Data & Index Use

Choosing the right bulls matters. Use the EBI and methane sub-index where available. Work with your advisor or breeding supplier to balance emissions with fertility, solids, and health traits.

System Fit

Low-emission genetics work best when supported by strong management. To maximise gains, ensure your system supports high-efficiency cows with good feed, health, and grazing infrastructure.

Implementation

Genetic selection fits naturally into your breeding decisions. With no extra work day-to-day, it’s one of the simplest ways to build climate efficiency. Here’s how to start.

Use high-EBI bulls. Select sires ranked highly for fertility, solids, and environmental efficiency. Over time, your herd performance will shift.
Track your herd. Use ICBF tools to monitor cow efficiency and emissions traits. Focus on high-performing replacements and cull low-efficiency animals.
Stay consistent. Genetic gains compound. Maintain a high-quality breeding programme each year to maximise climate impact by 2030 and beyond.

Behind the Research

ODOS Tech was founded by Cian White and Alejandro Vergara, two sustainability specialists with deep expertise in agricultural climate action.

Cian, a researcher at Trinity College Dublin with a background in environmental science, works on restoring nature to increase biodiversity on farms by using satellite images to track trees, hedgerows, and other habitats. Alejandro, a PhD researcher at University College Dublin, helps farmers measure their carbon emissions footprint and implement mitigation strategies to reduce their impact.

Together, they helped lead the carbon and nature-based work for the Farm Zero C project at Shinagh Farm, one of Europe’s first net-zero dairy pilots. At ODOS, they build smart, science-based tools to help agri-food businesses protect the environment and restore nature.

Research

Teagasc & ICBF EBI Studies

Joint research shows that each €10 increase in EBI reduces emissions per kg milk by 0.5-1.0 %. Top herds using genetic selection outperform on both emissions and profitability.

Farm Zero C Pilot

At Shinagh Farm, herd selection using high EBI and feed-efficiency traits showed strong reductions in emissions intensity without changing feed or infrastructure.

IPCC & Breeding Guidance

The IPCC identifies breeding for lower emissions intensity as a long-term climate strategy. Combined with feed and manure strategies, it offers a scalable path to reduce livestock climate impact.