Milk production & greenhouse gases : integrated modeling of feeding and breeding strategies to reduce emissions

WU thesis no. 577

Grazed and confused? : Ruminating on cattle, grazing systems, methane, nitrous oxide, the soil carbon sequestration question - and what it all means for greenhouse gas emissions

In the context of planetary boundaries on the one hand and the need for human development (in its widest sense) on the other, what role – if any – do farmed animals play in a sustainable food system? If they do have a role, which systems and species are to be preferred, in which contexts, at what scale and at what level of overall production and consumption? How could the required changes happen

The potential of future foods for sustainable and healthy diets

Altering diets is increasingly acknowledged as an important solution to feed the world’s growing population within the planetary boundaries. In our search for a planet-friendly diet, the main focus has been on eating more plant-source foods, and eating no or less animal-source foods, while the potential of future foods, such as insects, seaweed or cultured meat has been underexplored. Here we show that compared to current animal-source foods, future foods have major environmental benefits while safeguarding the intake of essential micronutrients. The complete array of essential nutrients in the mixture of future foods makes them good-quality alternatives for current animal-source foods compared to plant-source foods. Moreover, future foods are land-efficient alternatives for animal-source foods, and if produced with renewable energy, they also offer greenhouse gas benefits. Further research on nutrient bioavailability and digestibility, food safety, production costs and consumer acceptance will determine their role as main food sources in future diets

Nieuwe maat voor melkproductie : vergelijking melkgift koeien met verschillende droogstandslengte mogelijk met effectieve lactatie

De gebruikelijke maat voor lactatieproductie, de 305 dagenproductie, houdt geen rekening met de lengte van de droogstand of tussenkalftijd van de koe. Onderzoekers van Wageningen UR stellen daarom een nieuwe maat voor lactatieproductie voo

Future of animal nutrition: the role of life cycle assessment

The livestock sector poses severe pressure on the environment via the emissions of pollutants to air, water and soil, and via the use of scarce resources. This chapter elaborates on the role of life cycle assessment (LCA) to reduce environmental impacts of the pig and poultry sector, with special emphasis on the production of feed. First, the four phases of an LCA are described. Differences between attributional and consequential LCA, and variability in methods to account for land use change are discussed. It is concluded that harmonisation of methods and high quality inventory data are needed to improve interpretation of LCA results in the livestock sector. Second, the role of LCA in animal nutrition is discussed. Improving the production efficiency of crops and animals has been a major focus for reducing environmental impacts of livestock production. LCA implicitly combines information regarding crop and animal productivity, and creates understanding about the interaction between processes, and the impact of the entire production chain. Current applications of LCA are mainly attributional; results create understanding concerning the current situation, such as the environmental impact of a certain diet. To evaluate the impact of improvement options, consequential LCA is required. If a feed company increases its use of by-products, for example, the consequences of a decrease in availability of that by-product for other applications, such as biofuel production, need to be taken into account. A potential shortcoming of LCA is that is does not address the competition for resources between humans and animals, which occurs at a higher aggregation level. To determine an environmentally sustainable human diet, or to address the role of livestock in (global) food security, LCA needs to be combined with other modelling techniques that address environmental impacts of dietary choices at the national or international level

Future of animal nutrition: the role of life cycle assessment

The livestock sector poses severe pressure on the environment via the emissions of pollutants to air, water and soil, and via the use of scarce resources. This chapter elaborates on the role of life cycle assessment (LCA) to reduce environmental impacts of the pig and poultry sector, with special emphasis on the production of feed. First, the four phases of an LCA are described. Differences between attributional and consequential LCA, and variability in methods to account for land use change are discussed. It is concluded that harmonisation of methods and high quality inventory data are needed to improve interpretation of LCA results in the livestock sector. Second, the role of LCA in animal nutrition is discussed. Improving the production efficiency of crops and animals has been a major focus for reducing environmental impacts of livestock production. LCA implicitly combines information regarding crop and animal productivity, and creates understanding about the interaction between processes, and the impact of the entire production chain. Current applications of LCA are mainly attributional; results create understanding concerning the current situation, such as the environmental impact of a certain diet. To evaluate the impact of improvement options, consequential LCA is required. If a feed company increases its use of by-products, for example, the consequences of a decrease in availability of that by-product for other applications, such as biofuel production, need to be taken into account. A potential shortcoming of LCA is that is does not address the competition for resources between humans and animals, which occurs at a higher aggregation level. To determine an environmentally sustainable human diet, or to address the role of livestock in (global) food security, LCA needs to be combined with other modelling techniques that address environmental impacts of dietary choices at the national or international level

Comparing environmental impacts of beef production systems: A review of life cycle assessments

Livestock production, and especially beef production, has a major impact on the environment. Environmental impacts, however, vary largely among beef systems. Understanding these differences is crucial to mitigate impacts of future global beef production. The objective of this research, therefore, was to compare cradle-to-farm-gate environmental impacts of beef produced in contrasting systems. We reviewed 14 studies that compared contrasting systems using life cycle assessment (LCA). Systems studied were classified by three main characteristics of beef production: origin of calves (bred by a dairy cow or a suckler cow), type of production (organic or non-organic) and type of diet fed to fattening calves

Evaluation of a feeding strategy to reduce greenhouse gas emissions from dairy farming: The level of analysis matters

The dairy sector contributes to climate change through emission of greenhouse gases (GHGs), via mainly carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Replacing grass silage with maize silage is a feeding strategy to reduce enteric CH4 emission. The effect of this strategy on GHG emissions can be analyzed at three different levels: animal, farm, and chain level. The level of analysis might affect results and conclusions, because the strategy affects not only enteric CH4 emissions at animal level, but also other GHG emissions at farm and chain levels. The objective of this study was to determine if the level of analysis influences conclusions about the GHG reduction potential of increasing maize silage at the expense of grass and grass silage in a dairy cow’s diet. First, we used a linear programming (LP, maximizing labor income) dairy farm model to define a typical Dutch dairy farm on sandy soils without a predefined feeding strategy (i.e. reference situation). Second, we combined mechanistic modeling of enteric fermentation and life cycle assessment to quantify GHG emissions at all three levels. Third, continuing from the diet derived in the reference situation, maize silage was increased by 1 kg DM per cow per day at the expense of grass (summer), or grass silage (winter). Next, the dairy farm model was used again to determine a new optimal farm plan including the feeding strategy, and GHGs were quantified again at the three levels. Finally, we compared GHG emissions at the different levels between the reference situation and the situation including the feeding strategy. We performed this analysis for a farm with an average intensity (13,430 kg milk/ha) and for a more intensive farm (14,788 kg milk/ha). Results show that the level of analysis strongly influences results and conclusions. At animal level, the strategy reduced annual emissions by 12.8 kg CO2e per ton of fat-and-protein-corrected-milk (FPCM). Analysis at farm and chain level revealed first of all that the strategy is not feasible on the farm with an average intensity because this farm cannot reduce its grassland area because of compliance with the EU derogation regulation (a minimum of 70% grassland). This is reality for many Dutch dairy farms with an intensity up to the average. For the more intensive farm, that can reduce its area of grassland, annual emissions reduced by 17.8 kg CO2e per ton FPCM at farm level, and 20.9 kg CO2e per ton FPCM at chain level. Ploughing grassland into maize land, however, resulted in non-recurrent emissions of 913 kg CO2e per ton FPCM. At farm and chain levels, therefore, the strategy does not immediately reduce GHG emissions as opposed to what results at animal level may suggest; at chain level it takes 44 years before annual emission reduction has paid off emissions from land use change