The carbon footprint of milk from high-output dairy herds in NI is similar to lower-yielding systems, according to results from CAFRE’s environmental benchmarking programme.
“There is no significant difference between pasture-based versus totally confined. There are more differences within systems than between the systems,” said Michaela Tener from CAFRE.
“If someone is very efficient in a totally confined system, and someone is very efficient in a pasture-based system, they will have very comparable efficiency figures in terms of carbon per kilogramme of milk,” she said.
Speaking at an online event on Tuesday, Tener said that the main difference between high-and low-output systems surrounds where the main sources of greenhouse gases come from.
Tener said that 26% of emissions on typical dairy farms is attributed to purchased feed, 20% of emissions come from manure management and 11% is due to fertiliser
“In confined systems, an increased proportion of emissions will come from manure management. In a pasture-based system, there is generally an increased proportion of emissions from fertiliser,” she explained.
Figures from CAFRE’s new carbon footprint programme indicate that 38% of emissions on local dairy farms is due to methane from the digestion process in ruminants.
Tener said that 26% of emissions on typical dairy farms is attributed to purchased feed, 20% of emissions come from manure management and 11% is due to fertiliser.
Interestingly, only 2% of a typical dairy farm’s carbon footprint is due to fuel use and just 1% comes from electricity.
We have opportunities within our sector to make emission reductions, but it is a small proportion in terms of where we need to be
Figures from a local farm were presented which showed that improved efficiencies could help lower the farm’s total emissions by 4.6%.
This includes reducing fertiliser use by a third from 167kgN/ha to 111kgkgN/ha through more targeted use of slurry and inclusion of clover in swards.
Also, increasing the calving percentage from 80% to 90%, and reducing age of first calving from 26 months to 24 months.
“We have opportunities within our sector to make emission reductions, but it is a small proportion in terms of where we need to be,” Tener acknowledged.