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Minimizing greenhouse gas emissions in the dairy chain by optimizing concentrate composition in a dairy cow’s diet - Suzanne Brooshooft

The aim of the study was to optimize concentrate composition in a dairy cow’s diet based on the objective to minimize greenhouse gas (GHG) emissions along the milk production chain. Linear programming and life cycle assessment were used to simulate an average Dutch dairy farm on sandy soil and to account for GHG emissions from cradle to farm gate. Overall, it can be concluded that changing concentrate composition does have potential to reduce chain level GHG emissions.

Four scenarios were analysed: optimizing farm management with (1) fixed concentrate composition based on the objective to maximize labour income, (2) variable concentrate composition based on the objective to maximize labour income, (3) variable concentrate composition based on the objective to minimize GHG emissions, with a labour income at least equal to that of scenario 1, and (4) variable concentrate composition based on the objective to minimize GHG emissions and based on cost-effectiveness (in €/t CO2-eq reduced).

Results show little differences in farm plan between the three scenarios. All three scenarios had 48.1 ha of land, 78 dairy cows and an intensity of 14 152 kg milk/ha. Labour income was € 35 476 in scenario 1 and 3, € 40 103 in scenario 2 and € 27 476 in scenario 4. Total chain level GHG emissions in kg CO2-eq/t FPCM were 986, 1013, 907 and 710 for respectively scenario 1, 2, 3 and 4. Scenario 3 indicates that GHG emissions can be reduced significantly without reducing labour income. Cost-effectiveness of scenario 4 was €94 per t CO2-eq reduced. Concentrate ingredients in scenario 4 were palm kernel expeller, rapeseed, rapeseed meal Mervobest, soybean meal, soybeans heat treated and sugarbeet vinasse.

Overall, it can be concluded that changing concentrate composition does have potential to reduce chain level GHG emissions. Reductions in GHG emissions can already be met even without lowering labour income. Thus, no complete trade-off exists between labour income and reducing GHG emissions. However, further research is needed to assess the practical feasibility of the concentrate composition.

Student: SD Brooshooft

Supervisor: dr ir C van Middelaar

36 Ects