Care is needed when pursing low-methane genetics in livestock so it does not disrupt the genetic gains already achieved that increase profitability for farmers, AbacusBio director Peter Amer says.
Speaking in a webinar on breeding for low-methane-emitting animals, he said there was already a good story from sheep and cattle breeding and it is important not to disrupt these gains in the pursuit of adding on low-methane genetics.
As selection emphasis shifts away from traits that drive profitability onto a new methane trait, there is an opportunity cost as more and more emphasis is put on the new trait, he said.
Some have questioned whether selecting animals for feed efficiency is a better option than selecting for methane.
If a large, inefficient animal is replaced by a smaller, more efficient one, it could lead to a feed surplus, which the farmer would then feed to these or other animals.
“If we improve feed efficiency in a pastoral situation, we may not have any material impact on the national inventory or overall emissions,” he said.
This supported the argument for pursuing a methane trait, which improves both emissions and intensity and gross emissions.
Modelling showed that the additional benefits of this trait for the sheep, beef and dairy industries in New Zealand and Ireland came to 1-3% per decade, he said.
He believed this was a realistic amount that can be delivered through genetics.
AgResearch scientist Suzanne Row said the tools that are being developed to measure methane are becoming more advanced.
Low-methane genetics is a relatively benign trait that is available for selection and we just need to get on and measure it, she said. In sheep, every breeder can get a breeding value for methane emissions.
“There’s still a barrier, and at the moment we’re measuring using chambers.”
Those chambers are transported using a 3 tonne trailer and the resulting transport difficulties mean they do not have the scale yet for a genetic trait.
One of the alternatives scientists have been working on is an oral swab, where DNA is extracted from the swab and analysed. The predictions from this oral sample appear to be just as good as if it were taken from a gastric tube.
“That’s really exciting when we think about larger animals, animal welfare and non-invasive samples.”
Low-methane sheep have been bred for 15 years and scientists now know the differences between the high and low emitters and what the indicators are for what is occurring in the animal as well as potential predictors.
The webinar was organised by the New Zealand Agricultural Greenhouse Gas Research Centre and Irish agricultural research and development agency, Teagasc.
