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Research suggests the genetic gain achieved through Breeding Worth (BW) is helping reduce methane emissions intensity across the national herd.

The modelling looked at genetic improvement through BW and its impact on methane emissions intensity. The findings suggest that breeding for traits farmers already value can help improve methane emissions efficiency alongside productivity and profitability.

The research focused on methane emissions intensity, rather than the total amount of methane a cow emits. Emissions intensity measures the amount of methane produced per kilogram of milksolids, reflecting how efficiently feed is converted into milk.

International customers use emissions intensity to compare the environmental footprint of dairy products, and New Zealand dairy companies include it within their Scope 3 emissions targets.

Traits linked to lower methane emissions intensity

Researchers modelled how improving key economic traits within BW could affect the amount of feed required per unit of output and the methane emissions from milking cows and replacements. They focused on six traits: milk fat, milk protein, milk volume, fertility, functional survival and liveweight. Using these traits, they modelled the impact of the national herd’s genetic trends between 2019 and 2024 on methane emissions intensity.

Four traits appeared to account for most of the reduction in methane emissions intensity. Milk fat and milk protein lifted production, while fertility and functional survival kept productive cows in the herd longer and reduced the number of replacements needed.

Across the five-year period, methane emissions intensity was estimated to have fallen by 3.26% per kilogram of milksolids. At the same time, methane emissions per cow rose by 1.22%, reflecting higher feed demand as milk production increased.

The results suggest what many already know: genetic improvement helps make cows more efficient producers of milk. When more milksolids are produced for the same amount of feed energy, methane emissions intensity falls because each kilogram of methane is spread across more milk production.

The findings indicate that traits already selected to improve herd performance may also help lower methane emissions intensity, alongside the productivity gains they deliver.

Owl Farm puts research into practice

The modelling was applied at Owl Farm, near Cambridge. Over the same five years, the demonstration farm lifted its herd BW by around 24 points a year, while reducing methane emissions intensity by roughly 4%. Owl Farm’s herd BW now sits at 204, placing it in the top 4% nationally.

The cows with the lowest methane emissions intensity had the highest BW. The top 20% of cows in the herd produced 62kg more fat, 44kg more protein and 1,068 litres more milk than the bottom 20%. These results are consistent with research findings at a herd level, suggesting that the same traits that contribute to higher BW and improved herd performance could also be associated with lower methane emissions intensity.

Owl Farm demonstration manager and National Breeding Objective (NBO) committee member Jo Sheridan says farmers have been breeding for efficiency for a long time, and it’s encouraging to see those decisions also appear to improve methane emissions intensity.

“We have the resources to breed cows that have the best possible opportunity to convert that feed most effectively into milk.

“We just need to make sure we have more of these top performers in the herd.”

A long-term tool

The findings reinforce the value of using BW to guide breeding decisions, and of selecting replacements from high-BW cows. The research suggests that breeding better cows can help improve efficiency, productivity, profitability and methane emissions intensity.

The research was commissioned by NZ Animal Evaluation following a recommendation from the NBO committee. These findings are based on modelling rather than direct methane measurements, so further research is needed to confirm the results in practice. Farm management will also influence outcomes, including how higher-BW cows are fed and where additional feed comes from.

• This article was originally published in Inside Dairy November 2026-January 2027 edition

Source: DairyNZ