Greenhouse gas and alcohol emissions from feedlot steers and calves

Abstract

Livestock's contributions to climate change and smog-forming emissions are a growing public policy concern. This study quantifies greenhouse gas (GHG) and alcohol emissions from calves and feedlot steers. Carbon dioxide (CO) methane (CH), nitrous oxide (NO), ethanol (EtOH), and methanol (MeOH) were measured from a total of 45 Holstein and Angus steers and 9 Holstein calves representative of four different growth stages commonly present on calf ranches and commercial feedlots. Individuals from each animal type were randomly assigned to three equal replicate groups of nine animals per group. Steers were fed a high concentrate diet and calves a milk replacer and grain supplement. Cattle and calves were housed in groups of three animals in an environmental chamber for 24 h. The CO, NO, EtOH, and MeOH concentrations from the air inlet and outlet of the chamber were measured using an INNOVA 1412 monitor and CH using a TEI 55C methane analyzer. Emission rates (g head h) were calculated. The GHGs were mainly produced by enteric fermentation and respiration and differed across life stages of cattle. Compared with dairy cows, feedlot steers produce relatively less GHG. In general, ethanol and methanol, the most important volatile organic compound (VOC) group in the dairy sector, were below the lower limit of detection of the gas analyzer. The present data will be useful to verify models and to enhance GHG emission inventories for enteric fermentation, respiration, and fresh excreta for numerous cattle life stages across the beef industry.