As the pressure on producers to reduce methane emissions increases, could breeding be an important part of the solution? We find out more about ongoing work in the Netherlands and New Zealand
TEXT WICHERT KOOPMAN
Methane-produced emissions per kilogramme of milk produces varies considerably from cow to cow. Genetics accounts for 30% of the difference in methane emissions between cows, and breeding cows that emit lower levels of methane may be possible by 2025.
Reducing methane emissions is key to slowing and preventing further global warming. Methane is a powerful greenhouse gas (GHG) and is produced in many ways, including during the digestion of feed by ruminants. So dairy producers can make an important contribution towards reducing emissions. Adjusting rations and using feed additives can reduce methane emissions per kilogramme of milk by more than 20%. Methane produced per kilogramme of milk can also be influenced by management. A reduction of 12% per kilogramme of milk can, for example, be achieved by reducing the herd replacement rate from 30% to 25%, in combination with increasing average milk production from 27kg to 30kg per cow per day.
"Sniffer" technology: equipment measures methane emissions
Reducing the age at first calving for heifers also helps to limit the climate impact of milk production. A relatively new tool to tackle climate change is breeding cows that emit lower levels of methane. Wageningen Livestock Research’s Anouk van Breukelen is developing a breeding value for methane emissions. In an exploratory study, methane emissions were measured with ‘sniffers’ installed on 14 dairy units. Sniffers are added to robotic milking systems and measure methane concentration in the air exhaled by every cow during each milking. “The results revealed significant differences in methane emissions between cows. And 30% of these differences appear to be genetically determined,” says Ms van Breukelen.
Reduced emissions
“Reducing methane emissions has been added to the breeding goals for these herds, in addition to characteristics such as milk production, fertility, health and conformation. And we were able to demonstrate that emissions per cow can be reduced by 1% per year. This means methane emissions per cow in 2050 will be at least 25% lower than they are now. Breeding for lower methane emissions certainly offers prospects,” she adds.
More data is needed to develop a reliable breeding value for methane emissions and this is, among other information, being collected in a pilot project, involving CRV and dairy cooperative FrieslandCampina.
“Sniffers are being installed on 100 commercial dairy units with milking robots, and the data collected will be linked to a lot of other information about all the cows,” says Wageningen Livestock Research’s project leader Yvette de Haas.
By analysing this data, the research team hope to not only gain more insight into the heritability of methane emissions, but also into its correlations with other characteristics. “In order to add methane emissions to breeding goals, it is vital to know what its genetic connection is with other traits. What are the consequences of breeding for methane efficiency on milk production, feed efficiency, health or cow fertility? We still know very little about these correlations,” explains Ms de Haas.
Breeding value
She expects a breeding value for methane emissions will be available for use on farm by 2025. CRV is closely involved in Wageningen Livestock Research’s research and has also set up its own project in collaboration with Agrifirm. “On one of the farms where CRV measures the feed intake of individual cows, equipment to measure methane emissions has been installed to accurately determine how much the cows produce,” says CRV’s Maarten Moleman.
“Breeding and selecting for a lower methane production will mean that, generation after generation, there is an accumulation of favourable genes. And breeding can make an important contribution to reducing GHG emissions,” he adds.
Kiwis measure young-sire methane emissions
CRV New Zealand is, in partnership with breeding organisation LIC, measuring methane emissions from young bulls during the rearing period. A pilot trial, co-funded by the New Zealand government, showed significant differences in methane emissions between bulls. And these differences are largely genetically determined. This could mean it is possible to breed cows with lower methane emissions by selecting sires with lower methane emissions. The extent to which bulls pass on the genetic predisposition for methane emissions to their daughters will be examined in follow-up research. The relationship with other important characteristics will also be examined.