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
lected that naturally shed their wool each year. Considering meat from Merino flocks is not differentiated in
the meat supply chain (post slaughter), meat from purpose grown meat sheep was considered an appropriate
substitution product.
Comparison of the three methods showed a four-fold difference in greenhouse gas (GHG) emissions for
wool. The system expansion method resulted in total GHG of 7.6-9.2 kg CO2-e / kg greasy wool. Economic
allocation resulted in total GHG of 31.7-33.8 kg CO2-e / kg wool. The simple mass allocation approach resulted
in total GHG emissions of 8.1-8.3 kg CO2-e / kg greasy wool, which was similar to the results using
system expansion. The difference between the system expansion and economic allocation results were similar,
though much more pronounced, than the findings of Flysjö et al. (2011) for dairy production, which
showed system expansion to generate the lowest impacts for the primary product.
Economic allocation was sensitive to annual and cyclical changes in the value of wool and sheep meat. This
changed the GHG emissions allocated to wool by ± 30% between different years (over a five year period).
While mass allocation is generally not favoured, it has some merit for Merino systems. Because wool and
meat are closer to a joint production system than a typical primary product/by-product system, it follows that
the burdens should be allocated in a more even manner. Following a biological causality approach, wool and
meat are both protein based products that require broadly similar processes within the animal for production.
This offers a simple alternative to system expansion while generating similar results.
This study concluded that allocation was not required to differentiate between HG and LG meat, and highlighted
the sensitivity of allocation processes between wool and sheep meat. System expansion offers a useful
approach that reflects the dynamics of the Australian sheep meat market well, and is considered the most
suitable approach for further research in this industry.
References
Cederberg C & Stadig M. 2003. System expansion and allocation in Life Cycle Assessment of milk and beef
production. Int J LCA 8 (6) 350-356
Eady, S., Carre, A., Grant, T., 2011. Life cycle assessment modelling of complex agricultural systems with
multiple food and fibre co-products, J. Cleaner Prod. Volume 28, June 2012, Pages 143–149
Flysjö, A, Cederberg, C, Henriksson, M & Ledgard, S 2011, How does co-product handling affect the carbon
footprint of milk? Case study of milk production in New Zealand and Sweden, Int. J or LCA, vol 16, 420-
430.
Table 1. Co-products and allocation factors for Merino wool production
Economic
Mass Alloca- Allocation
Products
tion Factors Factors System expansion substitution products
Wool (greasy wool)
kg
14-15% 55-65%
Sheep sales (lamb + 85-86% 35-45% Purpose grown lamb and sheep meat from sheep
mutton – Live weight
meat enterprises. Substitution applied using a
basis) kg
factor of 95% to account for higher dressing percentage
of purpose grown sheep compared to
Merinos
690