342 Evaluation of the effects of biochar on diet digestibility and methane production from growing and finishing steers

Abstract

Abstract Two trials were conducted to evaluate the effects of biochar (0, 0.8, or 3% of diet dry matter) on diet digestibility and methane production in growing and finishing cattle diets. The growing diet consisted of 21% brome hay, 20% wheat straw, 30% corn silage, 22% wet distillers grains plus solubles (WDGS), and 7% supplement. The finishing diet consisted of 53% dry rolled corn, 15% corn silage, 25% WDGS, and 7% supplement. Biochar replaced fine ground corn in the supplement. Growing diets were evaluated over 6 periods in a switchback design, followed by the finishing trial with 3 periods in a crossover design using 6 steers (529 kg initial BW). Digestibility measures were taken over 4 d after at least 8 d of adaptation to diets followed by 2 d of gas emission measurements using headbox calorimeters. Statistical analysis included treatment and period as fixed effects and steer as a random effect with PROC IML of SAS used to generate coefficients for orthogonal contrasts. In the growing study, OM and NDF digestibility increased quadratically (P = 0.10) while OM digestibility tended to linearly decrease (P = 0.13) and NDF digestibility was not affected (P ≥ 0.39) by biochar inclusion in the finishing diet. Methane production (g/d) tended to decrease quadratically (P = 0.14) in the growing study and was decreased 10.7% for the 0.8% biochar treatment relative to the control. There were no statistical differences in methane production (g/d) in the finishing study (P ≥ 0.32). Methane production (g/kg DMI) from the 0.8% biochar treatment relative to the control was numerically reduced 9.5% and 18.4% in the growing and finishing studies, respectively (P ≥ 0.13). Although biochar is not an FDA-approved feed for cattle, initial research shows potential as a methane mitigation strategy in both growing and finishing diets.