Right‐Sided Congestive Heart Failure in North American Feedlot Cattle

BACKGROUND Anecdotal reports suggest the incidence of right-sided congestive heart failure (RHF) in feedlot cattle is increasing; however, the rate of occurrence and risk factors are largely unknown. OBJECTIVE The purposes of this study were to evaluate the risk of RHF over time and among feedlots, to characterize some of the risk factors for RHF, and to investigate how risk factors may affect the timing of RHF occurrence. ANIMALS The population at risk consisted of 1.56 million cattle that were placed in 10 Canadian feedlots during the years 2000, 2004, 2008, and 2012, and 5 US feedlots during the year 2012. METHODS A retrospective observational study was conducted. Variables, including year of feedlot entry, were evaluated for association with RHF using zero-inflated negative binomial and logistic regression models. Factors affecting time to RHF were evaluated using Cox proportional hazard regression analyzes. Death from digestive disorders (DD) served as a control. RESULTS The risk of RHF in Canadian feedlots doubled from the year 2000 to the year 2012 (P = .003). For every 10,000 cattle entering US feedlots in 2012, 11 cattle died from RHF and 45 cattle died from DD. The median time to RHF was 19 weeks. Cattle treated for bovine respiratory disease were 3 times more likely to die from RHF, and they died earlier in the feeding period. CONCLUSIONS A doubling of the incidence of RHF over a short time period is concerning, particularly for US feedlots situated at moderate altitudes in the High Plains.