Prediksi Emisi Gas Metana pada Ransum yang Mengandung Tanin dalam Sistem RUSITEC Melalui Komposisi Asam Lemak Terbang

Abstract

Greenhouse gas (GHG) emissions from agricultural sector account for about 25.5% from total global anthropogenic emission. While CO2 receives most of the attention as a factor relative to global warming, CH4 is one of the most important GHGs with the relative global warming potential of 25 time higher than that of CO2. Ruminant animals contribute towards the greenhouse effect through methane emission as a result of fermentation processes occurring in the rumen through microbial activities. This study is aimed to predict CH4 emissions from volatile fatty acid (VFA) profiles in the rumen simulation technique system. Data from a total of 6 experiments comprising of 25 treatments were entered in a database. Rumen simulation technique measurements were distinguished as experimental approaches. Methane was predicted from volatile fatty acid (VFA) profiles, i.e. acetate, propionate and butyrate based on rumen stoichiometry and compared with the measured CH4 emission. Prediction of enteric CH4 emissions was according to Hegarty or Moss model. The results predicted by both Hegarty and Moss models showed closer regression lines to the ideal line measurement of CH4 (where the observed values are equal to the predicted values) after adjustment by accounting for the actual hydrogen recovery. Comparing the both models, Moss equation (R2 = 0.766) is closer to the ideal line than that of Hegarty (R2 = 0.763). It was concluded that prediction of CH4 emissions in the Rusitec system via VFA composition could explain the variation of CH4 quite accurately but there was a considerable bias from the ideal line.