146 Effect of Sire on Methane Production

Abstract

Abstract The objective of this study was to determine if sires have a significant effect on methane (CH4) production in a feedlot setting. To reduce the emission of greenhouse gases from cattle, evaluating variables that are easy to manage and change becomes important for a solution. If sires influence methane production, selection can be used to reduce methane production in cattle as sire differences are indicative of a genetic influence. The data used in this study were obtained from Colorado State University (CSU), with animals from John E. Rouse Beef Improvement Center. Animals with methane data were included in this analysis if sire parentage was known. After filtering, there were 68 Angus cattle, with 56 sires and 12 heifers included in the study. A linear model fitting sire and pen to methane was used. RStudio was used for the general linear model, and significance values were generated. Individual CH4 emissions were collected using GreenFeed free-stall systems (C-Lock) in each of the four pens at the CSU Agricultural Research Development and Education Center facility in Fort Collins, CO. Methane emissions were measured over a 52-day period. The average animal age at the start of the period was 241± 15.76 days. After all collections were completed, the mean CH4 mass flow was 180.4 g/day with a median of 181.4 g/day. The minimum was 107.5 g/day with a maximum of 247.0 g/day. There were sex differences (P < 0.05) for (CH4) emission rate. Primary to this study, sires had a significant effect on (CH4) emission rates (P < 0.05). The range of sire means for methane production was considerable with the 1st and 3rd quartiles of 157.8 g/day and 209.6 g/day. In these data, sires significantly influenced the (CH4) emission rates of their progeny, and we believe selection could be used to reduce overall (CH4) emissions. With these results, however, additional analyses to fully understand if there truly is a genetic component to (CH4) production could be undertaken once additional data has been collected. These future studies need to consider the relationships between methane production and other traits such as average daily gain, dry matter intake, and weight as selection needs to occur while considering a system-wide perspective.