Dear Geraldo,

There are sentences more than data, because reduction on them are mainly due to carbon sequestration, and this aspect is normally not included in CLA so far. However, some data exist. You can find references to it in the capter attached.

Regards,

Alfredo J. Escribano.

Chapter Organic Livestock Farming: Challenges, Perspectives, And Str...

Geraldo,

I could point to a few research (listed below) where you will find values for measured methane (CH4) emissions from cattle metabolism (enteric fermentation) in shaded pasture such as those in Crop Livestock Forestry Integrated Systems (CLFIS).  These few conference papers are from your country, and you may perhaps know them already. 

Recently, we collaborated with few colleagues from UNESP to perform ‘a carbon footprint analysis of beef cattle fattening using three pasture management systems (including CLFIS) in Brazil’.  For this analysis (a paper based on this analysis has been accepted and will be available within few weeks), we did a large literature search.  From this literature search, I can tell you that there is very limited internationally published research on the subject of measured CH4 emissions under shaded pasture or silvo-pastoral systems. 

Several years back, I worked on cattle integrated systems with coconut and Nitrogen Fixing Tree (NFT) based agroforestry in Sri Lanka.  From this experience I know that the effect of trees on pasture quality is more complex, which cannot be explained by the effect of shade along.  Water relations are highly influenced by the tree root architecture relative to grass root system, depending on the tree species.  Pasture quality (i.e. crude protein content, NDF content and dry matter digestibility) can be highly variable due to the presence of trees and this could also affect the enteric CH4 emissions per unit of dry matter intake by cattle in these systems.  We used in-situ grown NFT fodder (such as those from Leucaena, Calliandra and Gliricidia) to feed cattle in the dry season and noted that cattle live weight gain and milk yield improved relative to cattle fed pasture grass along (please see my profile for few papers on this), which may have led to a decrease in CH4 emissions per unit weight of live-weight gained or milk produced, but we did not have facilities to measure enteric CH4 production directly at that time.  Based on the research from Australia (see Harrison et al. 2015, below) we can now believe that supplementing NFT fodder in these tree based integrated systems, could lead to a decrease in enteric CH4 emissions from cattle either directly or indirectly by improved cattle productivity.

-Susantha. 

Enteric methane emission of Nellore cattle in extensive grazing or integrated Systems https://www.researchgate.net/publication/281067313_Enteric_methane_emission_of_Nellore_cattle_in_extensive_grazing_or_integrated_systems

Enteric methane emissions of Canchim steers in five crop – livestock - forest integrated system

https://www.alice.cnptia.embrapa.br/alice/bitstream/doc/1022119/1/PROCIAB2015.00026.pdf

Methane emissions from ruminants in integrated crop - livestock systems.

http://www.ufrgs.br/gpep/documents/artigos/2014/pontesetal2014Methane%20emissions%20from%20ruminants%20in%20integrated%20crop-livestock%20systems.pdf

Harrison et al. (2015) Improving greenhouse gas emissions intensities of subtropical and tropical beef farming systems using Leucaena leucocephala. http://www.sciencedirect.com/science/article/pii/S0308521X15000360

Conference Paper Enteric methane emission of Nellore cattle in extensive graz...

Thanks Susantha, I agree that the correlation between shade and shaded systems, on one side, and the methane emission, on the other, present complex mediations. I hope your new paper can come soon!

Hi Geraldo,

This is the link for the publication (I mentioned) relating to the GHG analysis of beef cattle fattening under different pasture management systems in Brazil.

http://www.sciencedirect.com/science/article/pii/S0959652616302049

The analysis was based on primarily Brazilian research data gathered over the last few decades, and you may find the paper is very interesting to your question.

Cheers.

-Susantha