What have we learnt about breeding sheep for lower methane? – potential for genetic selection

blog by Dr Nicola Lambe, SRUC

The Challenge

Ultimately, we want to identify the best sheep to breed from to reduce the carbon footprint of the flock, whilst maintaining production. Can we produce more efficient ewes that also have lower methane output? We can increase production efficiency using the best breeding tools already available (e.g. to reduce parasites and increase outputs). To lower methane emissions, however, we need to understand variation between sheep (within and across breeds) and relationships with other important traits, so that we can harness this variation in the most effective and sustainable way.

Main findings

We found high levels of variation in methane emissions in each flock (typically the lowest 20% of sheep produced 15% less methane than the flock average). Methane emissions are under genetic control (16% of variation is due to the animal’s genes), and EBVs have been produced, with genomic EBVs following soon. There is substantial scope for selective breeding to reduce methane, but this should be implemented within a multi-trait selection index designed to improve productivity whilst reducing methane. Repeated measurements of methane from the same animal (measurements close together or at different life stages) rank similarly, suggesting we can measure animals just once on-farm to predict their relative methane output. Correlations of methane emissions with other breeding goal traits imply that breeding from animals that naturally produce less methane is unlikely to reduce rates of progress in lamb production or health.