260 Effect of Biochar Inclusion in Finishing Beef Cattle Diets on Enteric Methane Production and Performance

Abstract An experiment was conducted to evaluate the impacts of biochar on methane (CH4) and carbon dioxide (CO2) emissions and interim performance of finishing beef cattle. This experiment used crossbred beef steers (n = 128; initial BW= 347 kg ± 9 kg) fed a biochar sourced from pistachio shells (VGrid Energy Systems). The diet contained 61% dried rolled corn, 30% Sweet Bran (Cargill Corn Milling, Blair, NE), 5% wheat straw, and 4% supplement with Tylan (Elanco Animal Health) targeted at 9.7 mg/kg of dry matter (DM) and Rumensin (Elanco Animal Health) at 33.1 mg/kg of DM in a fine ground corn carrier. Two treatments consisted of a control (CON) group fed a diet containing no biochar and a biochar (BIO) group fed a diet with 0.5% biochar replacing 0.5% dried rolled corn in the diet. Cattle were implanted on d 0 with Revalor XS (Merck Animal Health). Pen was the experimental unit with 8 steers per pen and 8 replications. Interim data were collected on d 90 of the experiment. Four pen replications were rotated twice through a two-chambered barn equipped with open-circuit indirect calorimeters using a negative air pressure system. Within replicate, each pen of cattle was monitored in both chambers. LI-COR (Biosciences, Lincoln, NE) sensors were used to capture emissions (7700 Open-Path CH4 analyzer and 7500DS Open-Path CO2/H2O analyzer). Each replicate was monitored for 5 d in the pen chamber followed by 1 d manure contribution and 1 d used for baseline corrections. Cattle performance data were analyzed using the MIXED procedure of SAS with treatment as the fixed effect and emissions data were analyzed as a repeated measure. Feeding biochar tended to increase emissions of CH4 in g/d (194 g/d BIO and 176 g/d CON, P = 0.09) but had no other effects on CH4 in g/kg of dry matter intake (DMI) with 16.3 g/kg DMI BIO and 14.2 g/kg DMI CON (P = 0.27). Likewise, feeding BIO had no effect on CO2 as g/day (10854 g/d BIO and 10691 g/d CON, P = 0.78) or as g/kg of DMI (904 g/kg DMI BIO and 860 g/kg DMI CON, P = 0.34). Interim cattle performance showed no differences between treatments in interim body weight (529 kg BIO and 534 kg CON, P = 0.49) and average daily gain (2.02 kg/d BIO and 2.07 kg/d CON, P = 0.50). Dry matter intake (12.3 kg/d BIO and 12.1 kg/d CON, P = 0.45) was not different between groups, which resulted in no differences in feed efficiency (0.165 BIO and 0.169 CON, P = 0.23). Supplementing biochar at 0.5% of the diet DM did not decrease eructed CH4 (sligh