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The value of genetic selection in reducing economic losses from bovine respiratory disease complex in beef cattle feedlots
The U.S. inventory of beef cattle has declined since its peak in the 1980’s to levels present in the early 1960’s. Low cattle inventories have contributed to record high prices since 2009. The increased cattle values have also resulted in a subsequent increase in economic losses from disease. Reducing losses due to disease has become increasingly important in managing thin profit margins at feedlots. The objective of this study was to develop a bio-economic model to evaluate the economic cost of bovine respiratory disease complex (BRDC) in beef feedlots and estimate the potential net economic gain from using selection approaches to reduce BRDC prevalence. Treatment cost, mortality, and harvest data from approximately 1000 heifers and 1000 steers with similar numbers of cases and controls were taken from two commercial feedlots and two commercial processing facilities at harvest. These data were used to develop a Reed-Frost epidemiological model that simulated BRDC prevalence in a population of cattle on feed. Treatment cost was computed as a function of days on feed and the prevalence of cases. Losses due to mortality, and carcass quality discounts were also included to estimate total economic losses. Based on market prices, and carcass discounts, the average economic loss per BRDC case was estimated. To estimate the potential net economic gain from selection, the rate of genetic gain was estimated using a 16.2% national BRDC prevalence rate obtained over a 15 year period and an estimated heritability for BRDC susceptibility of 21% from the 2000 cattle evaluated in this study. An @Risk model was used to estimate a 20-yr time frame of genetic selection with stochastic BRDC prevalence rates using historical USDA data. The model compared net economic gains for cattle feedlots that used selection to reduce BRDC and feedlots that approached reducing BRDC without selection. This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68004-30367 from the USDA National Institute of Food and Agriculture.
Keywords: Bovine Respiratory Disease Complex, Economics, Epidemiology, Genetics