Performance and Estimation of Enteric Methane Emission from Fattening Vietnamese Yellow Cattle Fed Different Crude Protein and Concentrate Levels in the Diet

The objectives of this study were to estimate of methane emission from Vietnamese local fattening cattle fed different crude protein (CP) levels in the concentrate (experiment 1) and concentrate levels in the diet (experiment 2). Twenty four cattle with initial live weight (LW) of 150.3 ± 11.8 kg were used in the first experiment and 24 other cattle with initial LW of 145.1 ± 9.8 kg were used in the second experiment. Randomized complete block design was used in both experiments. In the first experiment, concentrate with four CP levels (10, 13, 16 and 19%) was fed at 1.5% of LW. In the second experiment, concentrate was fed at 1.0, 1.4, 1.8 and 2.2% of LW. In addition, in both experiments, cattle was fed with 5 kg native grasses/day (fresh basic) and rice straw was fed ad libitum. Enteric methane emission was estimated by the ruminant model. Initial inputs to the model were i) animal characteristics (age, body weight) ii) feed consumption and iii) the chemical composition of each feed ingredient. The study revealed that dry matter (DM) intake, meat productivity were effected by CP levels in the concentrate (P<0.05). Similarly, DM intake, meat productivity increased (P<0.01) linearly with increased concentrate levels. Increasing the CP level in the concentrate or the concentrate level in the diet resulted in decreased methane emission intensity (kilogram of product). Appropriate CP levels in the concentrate or the concentrate levels in the diet can be sonsidered as a solution to improve animal productivity while decreasing methane emissions per unit product of cattle production.