Greenhouse Gas Emissions from Beef Feedlot Surface Materials as Affected by Diet, Moisture, Temperature, and Time

A laboratory study was conducted to measure the effects of diet, moisture, temperature, and time on greenhouse gas (GHG) emissions from feedlot surface materials (FSM). The FSM were collected from open-lot pens where beef cattle were fed either a dry-rolled corn (DRC) diet containing no wet distillers grains with solubles (WDGS) or a DRC diet containing 35% WDGS. The FSM were collected, air-dried or mixed with 3.0 L of water to represent dry or wet conditions, and then incubated at temperatures of 5°C, 15°C, 25°C, or 35°C. Static flux chambers were used to quantify GHG emissions over a 14-day period. Flux data for each diet × moisture combination were analyzed using repeated measures in time. The largest GHG emissions occurred under wet conditions at temperatures of 25°C and 35°C. Flux values for these conditions typically were significantly greater than measurements obtained on the same day at 5°C and 15°C. Mean emissions under wet conditions for CO2, CH4, and N2O were 35, 121, and 278 times greater, respectively, than emissions from dry FSM. The 0% WDGS diet produced mean CO2 and N2O flux measurements that were 1.8 and 1.5 times greater, respectively, than those obtained for the 35% WDGS diet. The 35% WDGS diet, in contrast, produced a mean CH4 emission rate that was 6 times greater than the 0% WDGS diet. Management for GHG mitigation should include design and/or maintenance of pen drainage to speed drying as well as the use of modified animal diets

Greenhouse Gas Emissions from Beef Feedlot Surface Materials as Affected by Diet, Moisture, Temperature, and Time

A laboratory study was conducted to measure the effects of diet, moisture, temperature, and time on greenhouse gas (GHG) emissions from feedlot surface materials (FSM). The FSM were collected from open-lot pens where beef cattle were fed either a dry-rolled corn (DRC) diet containing no wet distillers grains with solubles (WDGS) or a DRC diet containing 35% WDGS. The FSM were collected, air-dried or mixed with 3.0 L of water to represent dry or wet conditions, and then incubated at temperatures of 5°C, 15°C, 25°C, or 35°C. Static flux chambers were used to quantify GHG emissions over a 14-day period. Flux data for each diet × moisture combination were analyzed using repeated measures in time. The largest GHG emissions occurred under wet conditions at temperatures of 25°C and 35°C. Flux values for these conditions typically were significantly greater than measurements obtained on the same day at 5°C and 15°C. Mean emissions under wet conditions for CO2, CH4, and N2O were 35, 121, and 278 times greater, respectively, than emissions from dry FSM. The 0% WDGS diet produced mean CO2 and N2O flux measurements that were 1.8 and 1.5 times greater, respectively, than those obtained for the 35% WDGS diet. The 35% WDGS diet, in contrast, produced a mean CH4 emission rate that was 6 times greater than the 0% WDGS diet. Management for GHG mitigation should include design and/or maintenance of pen drainage to speed drying as well as the use of modified animal diets