GHG emission in beef and leather production systems

The beef literature review was part of an overall project commissioned jointly by the Dairy Working Group from the Sustainable Agriculture Initiative Platform (SAI Platform) and the European Roundtable for Beef Sustainability to make an overview of greenhouse gas mitigation (GHG) options in beef and dairy and their degree of implementation.

Variation in the reported GHG emissions of beef production

The assessment showed a high variation in the reported GHG emissions of beef production. Different factors (e.g., intensive or extensive systems, origin of calves, organic or non-organic systems, diet composition, animal species, local or regional socioeconomic and market context) and also different methodological choices play a role in the variation of reported carbon footprint of beef in Europe.

The main contributors to GHG emissions of beef production

Based on the Food and Agriculture Organization (FAO) estimation from 4.6 Gt CO₂eq per year of livestock sector emissions, 2.5 Gt CO₂eq per year was from beef cattle. The most important sources of greenhouse gas (GHG) emissions in the beef sector are feed production (51% of the sector emissions) and enteric fermentation (43% of the sector emissions). Manure storage and processing (in total around 5% of the sector emissions) and other off-farm and post-farm activities including transportation (around 1% of total emissions) are the other important sources of GHG emissions in beef production systems.

Applied method and approach

For the literature review it is important to compare results which are based on the same methodology or approach. The studies which applied LCA methodology and IPCC emission guidelines were considered. Depending on the aim, different function units (FUs) including one kg of live weight, carcass weight, edible beef, or protein content can be used for the LCA of beef production. One kg carcass weight was defined as the main FU in this study and all results were updated based on the main FU. Because of the high level of variations for the post-farm stages (e.g., live animal transport, slaughtering and processing operations and market) the system boundary was limited to cradle to farm gate. For the environmental impacts of leather production, the attributional LCA approach was applied as well. Among the two most common FUs (kg and m² of finished leather) which applied in previous studies, m² was used as the main FU.

Comparison of beef production systems

Among the different beef production systems (e.g., intensive or extensive system, origin of calves, organic or non-organic system, diet composition, animal species, local or regional socio economic and market context), three classifications were defined as following:

• Origin of calves; including dairy-based and suckler-based systems. In a dairy-based system, the surplus male calves are separated from dairy cows and fattened and finished. However, in a suckler-based system beef originates from the suckler cows and their offspring.
• Diet composition; including concentrate-based diet (a diet with an average proportion of at least 50% concentrate and grain crops) and roughage-based diet (less than 50% concentrate in diet).
• Production method; including organic and non-organic beef production systems.

Among the 60 scientific publications reviewed, 21 studies met the defined criteria. Our literature scan showed the higher GHG emissions per kg carcass for suckler-based systems compared to the dairy-based system. In a dairy-based system, the emissions related to maintaining the mother cows are allocated to both products (milk and meat) while in a suckler-based system, emissions are attributed to just meat. The GHG emissions of organic farms were almost similar to the non-organic farms. However, the average GHG emission of organic farms in Europe was slightly lower than the non-organic farms due to fewer GHG emissions associated with the production of animal feeds. Because of the variation of reported CFs, the difference between organic and non-organic farms were not statically different in terms of GHG emissions. Comparison of a concentrate-based diet with the roughage-based diet showed the lower GHG emissions for concentrate-based diet. The higher enteric methane of roughage digestion and lower growth rate (longer finishing time) of calves in roughage-based systems can be the reasons for the higher GHG emissions of roughage-based diets compared to the concentrate-based one. Applying better feeding management to increase the growth rate in a roughage-based system and also shifting from low productive grasslands to the high productive ones reduces the CF of grass fed or pasture reared beef.

Potentials for GHG mitigation in beef production

The literature review showed a high potential for mitigating the GHG emissions in beef production systems. A high reduction of GHG emissions was seen in dairy- and concentrate-based beef systems. However, the feed-food competition issues should be considered when a concentrate-based system is recommended. In addition to changing the production system, some specific strategies can be considered including i) increasing the production efficiency by applying different feeding groups (based on the animal nutritional need), ii) reducing overfeeding by providing more fibre-rich roughages (in case the dairy × beef crossbred cattle is growing in herd with a higher feed efficiency), iii) reducing the number of unproductive animals and iv) modifying the dietary composition (e.g. use of feed additives, use of dietary supplements, reduction of N excretion by optimization of N content of diet).

Literature review of leather production

The literature scan showed a high variation because of methodological differences (e.g., system boundary and FU), quality of product and final use of finished leather. The average carbon footprint of reviewed papers was 24.6 kg CO₂eq per m² finished leather ranged between 7.75 and 53.7 kg CO₂eq per m² finished leather. Supplying energy and chemicals contributed most to the total GHG emissions of leather production. Conventional production systems had higher environmental impacts than the production systems with new technologies and applying new technologies was mentioned as the main strategy to reduce the carbon footprint of leather.