145 The Relationship of Methane Emissions with Stayability in Angus Cattle

Abstract

Abstract The dairy and beef industries have been identified as an important producer of methane emissions, yet little is known of its relationship to other economically relevant traits. Stayability (STAY) is a fertility and longevity-related trait with EPD (Expected Progeny Differences) representing predicted genetic differences in the probability of daughters remaining in the breeding herd until six years of age. Understanding the relationship between methane emissions and STAY might inform breeders of the consequences of selection on either trait. The objective of this study was to determine the relationship of methane emissions with STAY in Angus cattle (Bos Taurus) from Colorado State University’s John E. Rouse Beef Improvement Center located in southern Wyoming. A total of 123 animals (86 steers, 37 heifers) were sorted into four different pens where individual methane emissions were measured using a GreenFeed system (C-Lock, Rapid City, South Dakota). Stayability was evaluated using EPD values. A general linear model was used to calculate the regression of the average methane emission of each animal measured in grams/day (mean = 163.08, SD = 38.75, min = 87.72, max = 247.03) on STAY (mean = 0.59, SD = 0.69, min = -2.41, max = 2.36), including age in days (mean = 258.2, SD = 20.01, min = 200, max = 298) and pen as effects in the model. The regression of methane emission on STAY EPD was 0.52, however, it was not significant (P = 0.87). The effect of pen was significant (P < 0.001?). Age was significant, having an effect of 0.6794 (P = 3.93e-08). This suggests that younger individuals had decreased methane emissions. These preliminary results indicate that there is no significant relationship between methane emissions and STAY EPD.