Optimization of the national livestock sustainably

SUMMARY The objective of this work was to evaluate the calcium nitrate utilization in replacing to the soybean meal for ruminants diets under the mitigation of enteric methane aiming to determine the animal diet cost and the marginal costs for carbon rebates. The study was conducted in two stages, the first stage was in vitro gas production were performed in order to measure the enteric methane mitigation potential of the nitrate. The methane mitigation data were used in the second stage, which simulated a dairy farm with three feed systems: control system without nitrate, and systems with inclusion of 1.5 to 3% nitrate in the diet. The spreadsheets were used to evaluate the costs and revenues of each system resulting carbon credit sales of methane reduction in 10 years. The net present value (NPV) and the internal rate of return (IRR) were the indexes used in the financial evaluation.The carbon credit sale did not change the NPV significantly, however the inclusion of nitrate to 1.5 and 3% in animal feed showed economically feasible, because it reduced the diet value (R$5.89 e R$5.81/cow/day, respectively) in comparison to control diet (R$6.13/cow/day) besides contributing to the reduction and greenhouse gases. Therefore, the nitrate supplementation beside reduced the methane production, has the positive effect on the variable cost of the activity.