Australian Dairy Carbon Calculator

The Australian dairy industry is committed to a 30% reduction in greenhouse gas (GHG)  emissions intensity across the dairy supply chain based on 2010/11 levels.
To track industry progress Dairy Australia has developed a GHG accounting tool linked to DairyBase called the Australian Dairy Carbon Calculator. This tool enables farmers, advisers and industry to estimate emissions on farm and identify areas where there are opportunities for improvement.

Farm data from Dairybase is used to pre-populate the carbon calculator, saving time entering data. The carbon calculator provides a breakdown of emissions sources and potential abatement strategies.

Measuring actual emissions on farm is expensive  and the Australian Dairy Carbon Calculator is an internationally recognised tool that can be used to estimate on farm emissions. It can also be used to estimate the impact of changes in management practices on emissions.

 

  • Introduction
    The Australian Dairy Carbon Calculator provides a breakdown of the sources of GHG emissions on your farm.
    GHG emissions represent potential inefficiencies in your dairy system. The loss of methane and nitrous oxide gases into the atmosphere means that energy and nitrogen that could be directed towards production is being lost. Some level of loss is expected, but there are many opportunities within a typical dairy system to reduce greenhouse gases and achieve efficiency and profitability gains.


    For more info http://dairyclimatetoolkit.com.au/reducing-farm-emissions
  • Annual emissions in context
    Average emissions for a pasture based, 400-500 cow dairy farm are around 2,500 t CO2e per annum.  This is roughly equivalent to the emissions from a jumbo jet flying Melbourne to London return. To compare farms producing differing amounts of milk, emissions intensity is calculated by dividing total emissions by the amount of fat and protein corrected milk (FPCM; standard of 4.0% fat and 3.3% protein).  An average pasture based dairy farm with 400-500 cows has emissions intensity in the order of 1 kg CO2e/ kg FPCM, which is similar to 1 kg CO2e/ L milk or 13.5 kg CO2e/ kg MS.

    Emissions intensity for agriculture is the amount of emissions per unit of product.  Emissions intensity can be reported several ways such as kg CO2e per L of milk, per kg of milk solids (MS) or per kg of fat and protein corrected milk (FPCM).  Fat and protein corrected milk is used to compare milk with different dairy products.
  • Strategies to reduce emissions - by source

    There are two options to greenhouse gas emissions intensity – either reduce the absolute emissions per unit of product or increase the amount of product produced from the same level of inputs (increased efficiency). For example increasing the percentage of renewable energy utilised will reduce absolute emissions per unit of product. Alternatively, increasing feed utilisation efficiency will increase milk production per hectare and/or per cow which will reduce the GHG emissions intensity per unit of product.

    Some of the options for reducing on-farm GHG emissions have been provided below.

    • Feeding high quality feed to increase milk production and reduce GHG emissions
    • Applying nitrogen fertiliser at the right time and at a rate that is not in excess of plant/feed requirements
    • Being efficient with irrigation by maximising forage utilised per mega litre of water
    • Improving reproductive efficiency – which reduces the number of replacement heifers required
    • Improving energy use efficiency in the dairy
    • Selecting cow genetics for feed conversion efficiency.
    http://dairyclimatetoolkit.com.au/reducing-farm-emissions/understanding-emission-on-your-farm


  • Methane (CH4)

    Sources on dairy farms: Enteric methane and methane from manure & effluent systems.

    Enteric methane (CH4) from a cows rumen is the main source of GHG emissions on farm.   Around 55% of dairy emissions come from enteric methane produced by methanogen bacteria in the rumen that is then burped out by cows as part of the rumination process.  

    Methane production in the rumen of dairy cows is strongly associated with the digestion of forages, so high energy supplements (e.g. grain), or the use of fully mixed rations reduces methane per litre of milk. As a result, there is roughly 30% difference in emissions intensity between the two extremes of dairy systems – fully pasture fed (~17.5 t CO2-e/t milk solids) or fully lot fed (~12.5 t CO2-e/t milk solids).

    The proportion of an animal’s intake that is converted into methane is dependent on both the amount of feed eaten and the characteristics of the animal and the feed.

    Methane and nitrous oxide (N2O) from animal manure are the second largest source of emissions.  

    Mitigation strategies:

    • Extending herd longevity to reduce replacement rates. Reducing the herd replacement rate by 1% for every 100 milkers results in a savings of 1.5 t CO2e/annum.  For example, if you milked 300 cows and reduced the replacement rate from 25 to 20%, this would equate to a savings of 22.5 t CO2e/annum.
    • Identifying and culling less productive animals. The most productive cows make the most money and produce the least GHG emissions. Reducing the non-productive time for cows by 3 weeks (one breeding cycle) would save 12.6 t CO2e for every 100 milkers. For example, if the average inter-calving interval was reduced from 55 to 52 weeks for a milking herd of 500 cows, this would equate to a savings of 63 t CO2e.
    • Getting cows in calf, on time, every time.  This makes your herd more profitable and reduces GHG emissions intensity. For more information, see Dairy Australia’s InCalf Manual
    • Keeping cows comfortable. During extreme weather events this will reduce stress and associated losses in milk production. Trees & shrubs can provide shade and shelter, enhancing milk production as well as storing carbon, which may generate carbon credits. For more information, see Dairy Australia’s Cool Cows resources.
    • Diet manipulation for reducing enteric methane, for example:
    • Replacing supplements in the diet with a source of dietary fats/oils to a level no greater than 6% of total diet).
    • Feeding a high quality diet to increase milk production and reduce GHG emissions intensity. For more information, see Fert$mart
    • Increasing milk production per cow, while increasing total farm GHG emissions, will decrease the GHG emissions intensity of milk production.  For example, for a milking herd of 250 cows with a liveweight of 550kg consuming an annual average diet with a dry matter digestibility of 75% and crude protein of 18%, increasing milk production from 500 to 550 kg milksolids (MS) per cow/lactation, would increase milk production by 12,500 kg milksolids/annum. Total farm emissions would increase as a consequence of the additional milk production and by 31.6 t CO2e/annum. However, the additional milk production would dilute this additional GHG emissions, with the emissions intensity of milk production decreasing by 0.04 kg CO2e/kg MS.
    • NOTE: It is important to take into consideration the process by which the cows increase milk production.  If it is through increased grain feeding to improve diet quality, an estimate of the GHG emissions associated with the production and delivery of that grain needs to be taken into consideration.
  • Nitrous oxide (N2O)

    Sources on dairy farms: Cow dung, urine patches and N fertiliser through denitrification (direct loss). Nitrogen fertiliser is also lost through leaching/runoff and volatilisation (indirect loss).

    Nitrous oxide is emitted in the breakdown of nitrogen from dung and urine deposited in the paddock and N fertiliser applied to the paddock.  Nitrous oxide and methane are also produced from the effluent system.

    Reducing nitrogen fertiliser inputs by 1 t N per annum would save 6.1 t CO2e/annum.  For example, if you reduced your N fertiliser inputs by 2.5 t N/annum, this would equate to a savings of 15.3 t CO2e/annum.

    Mitigation Strategies:

    • Applying nitrogen at the right time, in the right place, with the right product and at the right rate to improve on farm nitrogen use efficiency and reduce GHG emissions.
    • Using effluent to offset fertiliser use. Each tonne of nitrogen fertiliser applied to pastures emits 1.9 t CO2e directly and 2.3 t CO2e indirectly. In addition, the manufacture of fertiliser (urea) emits 1.9 t CO2e. Therefore a 1-tonne reduction in the use of nitrogen fertiliser will reduce emissions by 6.1 t CO2e.
    • Soil-based strategies, such as improved drainage/irrigation and fertiliser management to reduce nitrous oxide losses associated with anaerobic conditions.
    • Targeted use of fertiliser. For example reducing Phosphorus (P) and Potassium (K) fertiliser use by 1 tonne would save 4.6 t CO2e and 0.3 t CO2e, respectively, due to the reduction in emissions from manufacturing.
  • Carbon dioxide (CO2)

    Sources on dairy farms: Electricity for shed and irrigation. Farm vehicles. Pre-farm embedded emissions.

    There are also carbon dioxide (CO2) emissions from farm diesel consumption and coal-fired power stations used to generate electricity used on dairy farms.  

    Reducing electricity consumption by 1000 kWh would save between 1.0 and 1.4 t CO2e/annum (range dependant on source of electricity with brown coal from Victoria the greatest emission factor).  For example, if your Victorian dairy farm used 75,000 kWh and you could reduce this by 10%, this would equate to a savings of 10.5 t CO2e/annum.

    Mitigation strategies:

  • Pre-farm embedded emissions
    Sources on dairy farms: products purchased off site but used on farm

    There are also emissions associated with production of grain and fertiliser bought onto the farm (pre-farm embedded emissions).