Risk factors associated with case fatality and treatment success following initial bovine respiratory disease treatment in feedyard cattle

Abstract

Bovine respiratory disease (BRD) is an important disease of fed cattle and knowledge gaps exist regarding factors predict­ing treatment success. The study objective was to identify po­tential relationships between risk factors known at the time of initial BRD treatment with 3 post-treatment outcomes: first treatment success (FTS), non-cause specific case fatal­ity risk (CFRALL), and cause-specific case fatality risk (CFRBRD). This retrospective analysis used generalized linear mixed models to evaluate relationships between covariates of interest with each outcome. Analysis included 132,521 individual-animal initial BRD treatment re­cords from 14 central U.S. feedyards (May 2017 to Dec 2020) with overall FTS of 67.8%, CFRALL of 10.0%, and CFRBRD of 6.3%. The FTS was associated (P < 0.05) with all covariates ex­cept sex, CFRALL was associated with all covariates, and CFR­BRD was associated with all covariates except day-of-week treated. Treatments early in the feeding phase (DOF 0-10, 11- 20) resulted in lower (P < 0.05) FTS (49.2% ± 0.8; 55.3% ± 0.8), higher (P < 0.05) CFRALL (12.5% ± 1.3; 12.6% ± 1.4) and higher (P < 0.05) CFRBRD (6.3% ± 1.1; 6.1% ± 1.0) compared to cattle treated on days 21-70. Rectal temperature in the 103.1-104.0 (39.4-40.0 °C) category had higher (P < 0.05) CFRALL (15.3% ± 1.5) and CFRBRD (9.2% ± 1.5) compared to other rectal tempera­ture categories. Specific risk factors including days on feed at treatment, sex and weight at the time of treatment were associ­ated with treatment outcomes. Results can be useful for defin­ing expectations following first treatment for BRD.