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
11. Milk and meat biophysical allocation in dairy farms
Jean Baptiste Dollé 1,* , Armelle Gac 2
1 Institut de l'Elevage, Building and Environment Department, F-62051 St Laurent Blangy, France, 2 Institut
de l’Elevage, Building and Environment Department, F-35652 Le Rheu, France, Corresponding author. Email:
jean-baptiste.dolle@idele.fr
For the dairy farming systems, where the main focus is to produce milk, the meat generated from surplus
calves and culled dairy cows is an important co-product. In Life Cycle Assessments (LCA), the environmental
burdens (GHG, etc.) must be distributed between these outputs. It is therefore necessary to determine
total GHG emissions of the production system, which include dairy cows and heifers, and to allocate them
between milk and meat. This issue has already been addressed in several studies (Cederberg & Stadig, 2003,
Flysjö et al., 2011). However, the ISO 14044 suggests that the allocation should be avoided as soon as the
system allows it, by subdivision of the multifunction process by sub-processes. This implies each subprocess
has to be precisely defined as dedicated to the production of one of the co-products and the input and
output fluxes of the whole system have to be attributed to each sub-process by a separated data collection or
by the use of a technical distribution rule. Our investigation on French dairy systems is based on the causal
relationship between the energy needed by animals on dairy farms and the milk and meat production. Then,
the biophysical allocation rule proposed is based on the technical functioning of the production system and
consists to separate energy needed for dairy cows and heifers. It is considered that the total energy of the
feed intake by cows is needed to produce milk (except pregnancy energy affected to the calf) and the total
energy needed by heifers for their growth is to produce meat (final live weight before calving) in relation
with meat avoided from suckler beef systems. In accordance to the IPCC guidelines 2006 to determine methane
emissions, energy demand for each category of animals (dairy cows and heifers) is evaluated by distinguishing
energy for maintenance, activity, growth, pregnancy and milk production.
This biophysical allocation has been tested on French dairy systems. The assessments highlight that energy
affected to milk (maintenance, activity, growth and milk production) represent 73% of the total energy
needed by the dairy herd (dairy cow + heifers) and the energy affected to meat (calving+ heifers) correspond
to 27%. This ratio, applied to allocate GHG from dairy system to milk and meat, has been compared to
milk/meat ratios obtained with other allocation approaches: protein allocation used by FAO, IDF allocation
(IDF - 2010), system expansion and economic allocation (Table 1). The distribution of environmental burdens
to milk and meat varies in a range of 72-88%. The ratio obtained with biophysical allocation is close to
the one with system expansion (meat from beef production system) but far from values observed with protein
and IDF allocations. Applied in French dairy systems, these different allocation rules have an important incidence
on carbon footprint. For milk and meat, carbon footprints at farm gate range respectively from 0.79 to
0.97 kg CO2eq/kg of milk and from 4.4 and 9.5 kg CO2eq/kg of live weight (Fig. 2).
The allocation choice for handling by-product is crucial for the outcome of the final carbon footprint of both
milk and meat. This choice is often taken from a dairy production point of view but it should also consider
that culled dairy cows represent a significant share of the total cattle meat production (40-50% in France).
Consistency concerning allocation in LCA studies on dairy and beef system, but also on all animal production
(pigs, poultry) should then be found. This is allowed by biophysical allocation, which also has the advantage
of being related to breeding practices (feed intake, forage, etc.) and showing the environmental gain
allowed by mitigating techniques.
References
Cederberg C., Stadig M., 2003. System expansion and allocation in life cycle assessment of milk and beef
production, Int J LCA, 350-356.
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, J Life cycle assessments,
16, 420-430.
IDF, 2010. Bulletin of the IDF n°445/2010.
IPCC 2006, 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Prepared by the National
Greenhouse Gas Inventories Programme, Eggleston H.S., Buendia L., Miwa K., Ngara T. and Tanabe K.
(eds). Published: IGES, Japan.
ISO 14044: 2006. Environmental Management - Life Cycle Assessment - Requirements and guidelines
665