Effect of Biochar Supplementation on Grazing Beef Cow and Calf Performance, Enteric Methane and Carbon Dioxide Emissions, Fecal Egg Counts and Fecal Nutrient Composition

A three-year beef cow grazing study (2020-2022) was conducted to evaluate the effects of biochar supplementation on grazing cow performance, ruminal fermentation, fecal egg and oocyst count, fecal nutrient composition, and enteric methane (CH4) and carbon dioxide (CO2) emissions. Each year, forty-eight spring-calving Angus beef cows (BW = 669 95 kg; mean STD) stratified by BW, were randomly assigned to 1 of 2 treatments. Treatments included either (i) pelleted supplement with biochar (Biochar; 405 g/d) inclusion at 2.2% of DMI or (ii) control pellet (Control; base fiber - no biochar). Twenty-four ha meadow bromegrass (Bromus riparius Rehm.)-alfalfa (Medicago sativa L.) paddocks (8.6% CP, 51.1% TDN) were assigned to each treatment group for the 92-d grazing trial. Enteric CH4 and CO2 emissions were measured using SF6 tracer gas technique. Cow and calf performance, rumen fluid parameters were not (p 0.05) affected by biochar supplementation. During trial biochar supplementation reduced fecal oocyst (Eimeria spp.) count (p 0.011; 3.9 vs. 15.0 count/g DM) but increased carbon:nitrogen ratio (p 0.029; 26.1 vs. 21.3) relative to initial measurements. The enteric methane emission reduction in response to biochar supplementation at 2.2% of DMI, was negligible (~6.0% reduced compared to control).