LCA Food 2012 in Saint Malo, France! - Manifestations et colloques ...

GROUP 1, SESSION A: ANIMAL PRODUCTION SYSTEMS 8 th Int. Conference on LCA in the
Agri-Food Sector, 1-4 Oct 2012
12. Functional unit and reference flow in the dairy cow LCA
Chun-Youl Baek 1 , Kun-Mo Lee 1,* , Kyu-Hyun Park 2
1 Department of Environmental Engineering, Eco-product Research Institute, Ajou University, Korea,
2 National Institute of Animal Science, Suwon, Korea, Corresponding author. E-mail: kunlee@ajou.ac.kr
Functional unit in LCA defines the functional performance characteristics delivered by the product system,
here livestock. It serves as denominator in normalising the input and output data (environmental load: EL) of
a product system. Normalised EL is intended implicitly and explicitly for comparison between processes and
activities in a given product system, or between different product systems. Defining functional unit of an
industrial product is less complicated compared with that of a livestock. This is mainly because of the difference
in functional performance characteristics of the two, where the former possesses fixed attribute while
the latter variable attributes. Reference flow is an amount of product needed to fulfil the function of a product
system.
The objective of this paper is to investigate the effect of product attributes on the functional performance
characteristics in defining functional unit and reference flow. A dairy cow was chosen as the target product
for the livestock LCA and a typical size dairy farm of 65 heads of cows with different stages in growth in
Korea was chosen to gather input and output data. A dairy cow undergoes different stages in its life cycle
including calf, heifer, lactating cow and dry cow with a life span of average five (5) years. Different life cycle
stages of a cow means composition of a cow in a farm during the life span of a cow of five years may
influence the variability of the EL data from a cow. Thus, composition of a cow in a farm should be clearly
defined in the reference flow.
Key findings of this paper include: functional unit should be defined based on the functional performance
characteristics delivered by the product, reference flow should be one cow with known composition and life
span, and composition of cows in a farm may vary depending on the number of heads the farm houses which
will affect LCA results. A stable composition should be used for defining reference flow in the dairy cow
LCA.
References
Steinfeld, H., Gerber, P., Wassenaar, T., Castel, V., Rosales, M., De Haan, C., 2006. Livestock's long
shadow: environmental issues and options, FAO, Rome, Italy.
De Vries, M., De Boer, I.J.M., 2010. Comparing environmental impacts for livestock products - A review of
life cycle assessments, Livestock Science, 128, 1-11.
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