Emissões de metano entérico em búfalas na Amazônia Oriental: TIER 2 e hexafluoreto de enxofre

Abstract

In Brazil, agriculture and livestock are considered major emitters of greenhouse gases (GHG), with animal production and land being significant contributors. In this paper we compare the enteric methane emissions through the use of TIER 2 methodology, which considers the animal category, the production system, and diet type; we also used the sulfur hexafluoride (SF6 ) tracer gas technique. Experimental data were obtained from the PECUS Project. Twenty adult buffaloes were kept in individual stalls and fed with four diets consisting of 0.00, 0.25, 0.50 and 1.00% levels of palm cake (Elaeis guineensis). The diets were similar in digestibility and metabolizable energy in both methodologies. The results showed similar emission averages among the methodologies, except for the 1% level of palm cake. Thus, TIER 2 can be considered a good estimator of enteric methane emissions when the nutritional composition of the diet and other animal characteristics are known. Measurements with trace gas SF6 show good sensitivity to assess enteric methane emissions; however, they involve high costs, basically associated with the animals and their diet, skilled workers, equipment for sampling, and laboratory facilities.