Nutrient utilization and methane emissions in Murrah buffalo calves fed on diets with different methanogenic potential

The objective of the present study was to evaluate the routine ingredients in ruminant feed (grains, agro-industrial byproducts and oilseed cakes) and their combinations for methanogenesis in vitro and to analyze the efficacy of least vs. most methanogenic diet formulations in Murrah buffalo calves. Methane was estimated by in vitro gas production technique. The concentrate mixtures were prepared by combining lower methanogenic ingredients from each category. Alike higher methanogenic ingredients were mixed to formulate concentrate mixtures. Six concentrate mixtures were formulated with metabolizable energy (ME) of 13 MJ/kg and crude protein (CP) of 20%. Their composition is as follows: Cl (sorghum, rice bran, mustard cake-deoiled (DOMC):: 50, 10, 40), C2 (sorghum, wheat bran, DOMC:: 45, 20, 35), C3 (sorghum, wheat bran, DOMC, cotton seed cake (CSC):: 43, 15, 32, 10), C4 (sorghum, rice bran, DOMC, CSC:: 40, 15, 30, 15), C5 (maize, gram churi, soybean meal (SBM):: 30, 50, 20) and C6 (maize, wheat bran, SBM:: 37, 38, 25). Among them two lower and one higher methanogenic concentrates were chosen and Lucerne fodder was mixed to prepare three rations viz. TLM1 (treatment low methane 1), TLM2 (treatment low methane 2) and THM (treatment high methane). Evaluation of the diets in Murrah buffalo calves (BW, 132 +/- 6 kg) was done by SF6 tracer technique. There was no significant variation in intake, nutrient digestibility and N retention rate of the rations. Energy loss via methane was higher from THM compared to TLM1 and TLM2 fed group. The loss accounted 13.83% of digestible energy and 16.08% of metabolizable energy of THM ration. Methane loss was lowered by around 10.4% in TLM1 and TLM2 fed group compared to THM. Feed from lower methanogenic ingredients were effective in reducing percentage of dietary energy lost via methane in buffalo calves.