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Quantification of methane emission in Murrah buffaloes fed different energy diet at varying temperature humidity index period in tropical environment
The objective of the present study was to quantify the enteric methane emission in Murrah buffalo heifers at high (summer) and low (winter) temperature humidity index (THI) period fed different energy level diets. Thirty six growing Murrah buffalo heifers of average body weight (158.51 ± 16.5 kg) were distributed into three groups of six animals each separated based on their body weight and fed for the period of 120 days each during summer (high THI, 78-85) and winter (low THI, 50-61). The animals were fed on three different levels of metabolizable energy (ME) content and the control ration (T1) having ME content according to ICAR (2013) and T2 and T3 were having 115% and 85% ME than control respectively, in total mixed (TMR) based ration. SF6 tracer gas technique was used to quantify the enteric methane emission by the animals. Methane emission (g/day) of control and high energy (T1 and T2) group was lower (P < 0.05) than low energy (T3) fed group in both season. Methane losses as percentage of gross energy (GE) intake was lower (P < 0.01) during winter season. However, in low energy treatment group (T3) at both seasons these values are higher than the IPCC recommended value (6.5%) for calculation of national inventory of greenhouse gas emission from enteric sources. In between season ADG (kg) was higher (P < 0.01) in winter season and among the treatment groups it was higher (P < 0.01) in high energy group (T1, T2). Higher (P < 0.01) digestibility of DM, OM, NDF and ADF was reported in control and high energy fed group. While in summer season digestibility of DM, OM, CP and ADF was higher (P < 0.01) than the winter season. It can be concluded that energy levels significantly (P < 0.05) affect methane emissions and was lower in control and high energy fed group (T1 and T2). However, while quantifying methane emission in changing THI period at different season it did not show any significant variation.
AN17187 Accepted 29 August 2017
© CSIRO 2017