Sustainability & efficiency

Modelling the industry effects of incorporating direct methane traits into New Zealand national breeding objectives

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Abstract

This study presents a comprehensive modelling framework to evaluate the potential of genetic selection in reducing enteric methane emissions within New Zealand's dairy, beef, and sheep sectors. Recognizing the substantial role of ruminant livestock in national greenhouse gas (GHG) emissions, the research targets robust, science-driven mitigation strategies that safeguard productivity and profitability.Selection index theory was employed to simulate long-term impacts of incorporating direct methane and feed intake traits into national breeding objectives. Methane yield (g CH₄/kg DMI), methane production (g CH₄/animal/day), and residual feed intake were defined as key traits. Genetic parameters were sourced from both literature and industry databases, and economic values were calculated across varying carbon price scenarios. Model outputs projected genetic responses in conventional and methane-specific traits and were translated to industry-level impacts using population data, global warming potential coefficients, and sector-specific economic assumptions.Results indicate that, under plausible scenarios for trait recording, evaluation, and selection, gross methane emissions could be reduced by 0.5 to 3% by 2040, doubling to 1 to 6% by 2050. The magnitude of reductions depends on the balance between conventional and methane-focused genetic gains, as well as measurement accuracy and genetic correlations. More pronounced reductions may be realized through improved proxy measurements, accelerated breeding programs, and increased selection pressure on methane traits. For each scenario, an implicit carbon price was able to be calculated as the opportunity cost of shifting selection emphasis from profit traits to carbon, with this opportunity cost ranging from -$385 to $223 per tonne of CO₂e. Certain scenarios incorporating feed efficiency yielded negative opportunity costs, suggesting potential economic benefits to farmers.The modelling underscores the strategic value of integrating feed intake recording with methane measurement, especially in dairy and beef sectors, for both profitability and environmental benefits. Notable knowledge gaps remain: namely, the adjustment of methane breeding values for feed intake and genetic correlations across animal classes and production systems. The study also discusses trade-offs, including possible antagonism between methane and feed efficiency traits, and impacts on animal resilience.In summary, genetic selection represents a promising avenue for GHG mitigation in New Zealand livestock, with further improvements contingent on closing identified knowledge gaps and refining breeding objectives.

Keywords: 2026

How to Cite:

Amer, P., Hely, F., Howes, N. & Kenny, D., (2026) “Modelling the industry effects of incorporating direct methane traits into New Zealand national breeding objectives”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2286269. doi: https://doi.org/10.31274/wcgalp.23900

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