Management practices associated with the rate of respiratory tract disease among preweaned beef calves in cow-calf operations in the United States

Objective—To assess associations between herd management practices and herd-level rates of bovine respiratory disease complex (BRDC) in preweaned beef calves in US cow-calf operations. Design—Cross-sectional survey. Sample—443 herds weighted to represent the US cow-calf population. Procedures—Producers from 24 states were selected to participate in a 2-phase survey; 443 producers completed both survey phases and had calves born alive during the study period. Data from those respondents underwent multivariable negative binomial regression analyses. Results—Bred heifer importation was associated with lower BRDC rates (incidence rate ratio [IRR], 0.40; confidence interval [CI], 0.19 to 0.82), whereas weaned steer importation was associated with higher BRDC rates (IRR, 2.62; CI, 1.15 to 5.97). Compared with single-breed herds, operations with calves of 2-breed crosses (IRR, 2.36; CI, 1.30 to 4.29) or 3-breed crosses (IRR, 4.00; CI, 1.93 to 8.31) or composite-herd calves (IRR, 2.27; CI, 1.00 to 5.16) had highe...