Irish grain can help to reduce emissions from milk production

Ireland’s tillage area accounts for approximately 7% of the total agricultural land, or 350,000ha. Grain production averages two to 2.4 million tonnes annually, dominated by barley and wheat, followed by oats, oilseed rape and beans. Of the total tonnage produced, approximately one million tonnes are traded annually. Ireland is not self-sufficient in grains for animal feed and imports about five million tonnes per year of products like maize, soybean meal, distillers’ grains, maize gluten, wheat and beet pulp.

These imported feed materials can carry a higher carbon footprint due to lower yields, cultivation practices, transport and land-use change in exporting countries.

AgNav

The AgNav platform, developed by Teagasc, ICBF and Bord Bia, provides a digital decision-support tool to help farmers quantify and reduce agricultural emissions. Originally designed for cattle systems, it now includes a tillage module to assess the carbon footprint of Irish grain production.

Results from AgNav show that the carbon footprint of Irish grains is low by international standards, typically 170kg to 250kg CO2e per tonne.

Incorporating straw residues enhances soil carbon sequestration, with oats and winter wheat often approaching a net zero GHG balance.

Fertiliser management and crop yield are the key drivers of life-cycle emissions: higher yields and optimised nitrogen fertilisation significantly lower the carbon intensity per tonne of output.

GHG: native versus imported grains

Replacing imported feed grains, especially those linked with deforestation, with Irish-grown cereals can substantially reduce the carbon footprint of animal feeds, and consequently of milk and meat produced on Irish farms.

Table 1 highlights the difference in the carbon footprint of native Irish grains, relative to imported grains.

Use of concentrates in dairy

The average Irish dairy cow consumes approximately 1,250kg of concentrate feed per year. Much of this material is imported. Native cereals, particularly barley, oats, wheat and beans, could replace a large proportion of the imported ingredients without compromising feed energy or protein content. Given that feed accounts for roughly 12-15% of total dairy system emissions, improving the carbon profile of feed offers an important abatement opportunity.

Emission reductions from native grain use in dairy feed

The GHG intensity of conventional ration using all imported feed ingredients outlined below is 0.83 kg CO2e/kg of ration (Table 2). When imported grain, and protein sources are replaced with native grains (64% of the ration), the GHG intensity reduces to 0.42 kg CO2e/kg of ration, or a 50% reduction. Both rations deliver similar energy and protein concentrations.

Feeding 1.25t of the native ration per cow per year reduces total emissions per cow by about 520kg CO2e, or a 7.4% reduction in GHG intensity per kg of fat and protein corrected milk.

This reduction is achieved solely through ingredient sourcing changes, without capital investment or alterations to herd management.

Comparison with MACC measures for dairy systems

Teagasc’s Marginal Abatement Cost Curve (MACC) identifies several key mitigation measures for Irish dairy systems (Table 3). Adopting native grain-based feed compares favourably with many of these established technologies.

The potential of a 7% reduction in the carbon footprint of milk from using 64% native grains in the ration would place this measure on a par with mid-tier MACC options. Unlike those measures, it requires no capital investment or major practice change, simply a shift in sourcing and feed formulation.

Although there isn’t enough native grain to meet the entire feed demand of the dairy industry, there is sufficient native grain to include it in a significant proportion of herds, which may suit certain supply chains.

It is important to note emissions embedded in imported feeds are not counted in Ireland’s national GHG inventory. Therefore, substituting native grain mainly reduces milk carbon footprints rather than the total GHG emissions from agriculture. Nevertheless, this measure strengthens Ireland’s sustainability credentials, reduces reliance on imports, and promotes circularity within Irish agriculture.