Retrospective analysis of risk and timing of death from right heart failure in United States and Canadian feedlot necropsied cattle.

Objective: To evaluate the risk and timing of right heart failure (RHF) in feedlot cattle.

Animals: Study population consisted of 1,717,356 cattle (5,527 cohorts) in 13 US and Canadian feedlots. There were 1,336 RHF diagnosed at necropsy.

Procedures: Multivariable models were utilized to evaluate risk and timing of RHF death.

Results: Arrival year was associated with RHF and was influenced by arrival quarter on the magnitude of risk of RHF (P < .01), but no linear increase over years was identified. The impact of feedlot elevation on RHF was modified by breed (beef, dairy, or dairy-cross; P < .01) with beef cattle in the highest elevation category having 0.54 times the risk of RHF as dairy cattle in the same elevation category (LCL = 0.31; UCL = 0.962). Cattle that died due to RHF and were treated for bovine respiratory disease died 11 days (LCL = 1.33, UCL = 20.2 days) sooner than cattle never treated for bovine respiratory disease (P = .03). Cattle breed was associated with RHF timing (P = .01), and dairy-cross cattle RHF cases died approximately 37 days earlier (SE = 13.0 days; P = .01) compared to beef cattle.

Clinical Relevance: This research showed demographic factors associated with RHF and their respective influence on risk and timing of RHF. Risk rates of RHF were similar to previous research. This could allow for comparisons across different feedlot populations, using different diagnoses at necropsy and RHF risk/rates do not appear to be increasing.