Bovine Respiratory Disease (BRD) is the costliest disease facing the cattle industry. Therefore, the objective of this study was to better understand the genetic component of underlying resistance to bovine respiratory diseases. The focus of this study was to better understand the genetic differences between cattle that were more susceptible and/or more resistant to BRD. Data from Iowa State University’s cattle at the McNay Research Farm have been used to try to determine the best phenotypic measurement with which to identify resistant cattle to ultimately help producers in the selection of this economically relevant trait.