Abstract

Global warming attributed to methane emissions from livestock presents a significant global challenge to the agricultural sector. Although opportunities exist in intensive systems for feed additives, the only proven tool for permanent mitigation at a national level, across sectors, is animal breeding. It has been reported that enteric methane emission is a heritable trait, and that breeding is an effective mitigation strategy. The impacts of incorporating methane into existing breeding schemes are less understood. Selection for reduced methane emissions (measured by portable accumulation chamber; PAC) along with increased productivity (NZMW+FEC+DAGS+MEAT index) was implemented in 2017 in the Woodlands 2638 flock. The economic weighting for methane was NZ$100/tonne GWP100 CO2e. The economic weights for existing traits were unchanged. Breeding value trends per year for flock 2638 and the Dual Purpose industry average for born 2018 to 2023 progeny were estimated as -0.95 vs -0.01%, -0.2 vs 0.06%, 0.18 vs 0.12kg, 133 vs 89 cents, and 185 vs 110 cents for PACCH4gBV%, PACCO2gBV%, LW8gBV, NZMW and NZMW+FEC+DAGS+MEAT indexes respectively. Gene flow calculations suggest that methane emissions could be reduced by 27% by 2050 while increasing per head productivity by $51.80. Continuation with current industry progress would achieve a 2.8% reduction in methane emissions and $30.80 increase in per head productivity. In summary, methane emissions can be reduced while also increasing productivity faster than current industry progress.

Booker, F., McEwan J.C., and Rowe S.J.

New Zealand Journal of Animal Science and Production, Volume 84, Oamaru, 4-6, 2024