The objective of this study is to better understand the genetic component to bovine respiratory disease (BRD). The focus of this study is to research the genetic link between cattle that are more susceptible and cattle that are more resistance to BRD. Data from Iowa State University’s cattle at the McNay Research Farm and the Beef Teaching Farm, along with Iowa cattle producers, will be used to try to determine the best phenotypic measurement of resistance in cattle to ultimately help producers in selection of this economically relevant trait.