Hanzlicek Gregg A, Renter David R, White Brad J, Wagner Bruce A, Dargatz David A, Sanderson Michael W, Scott H Morgan, Larson Robert E
Kansas State Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Kansas State University, Manhattan, KS 66502, USA.
J Am Vet Med Assoc. 2013 May 1;242(9):1271-8. doi: 10.2460/javma.242.9.1271.
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.
Cross-sectional survey.
443 herds weighted to represent the US cow-calf population.
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.
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 higher BRDC rates. Operations classified as supplemental sources of income had lower BRDC rates (IRR, 0.48; CI, 0.26 to 0.87) than did operations classified as primary sources of income. Reported feed supplementation with antimicrobials was positively associated with BRDC rates (IRR, 3.46; CI, 1.39 to 8.60). The reported number of visits by outsiders in an average month also was significantly associated with herd-level BRDC rates, but the magnitude and direction of the effects varied.
Management practices associated with preweaning BRDC rates may be potential indicators or predictors of preweaning BRDC rates in cow-calf production systems.
评估美国母牛-犊牛养殖场断奶前肉牛犊群管理措施与牛呼吸道疾病综合征（BRDC）的畜群发病率之间的关联。
横断面调查。
443个畜群，经加权后代表美国母牛-犊牛群体。
从24个州选取生产者参与两阶段调查；443名生产者完成了两个调查阶段，且在研究期间有存活犊牛出生。对这些受访者的数据进行多变量负二项回归分析。
引入经配种的小母牛与较低的BRDC发病率相关（发病率比[IRR]，0.40；置信区间[CI]，0.19至0.82），而引入断奶公牛与较高的BRDC发病率相关（IRR，2.62；CI，1.15至5.97）。与单一品种畜群相比，拥有两品种杂交犊牛（IRR，2.36；CI，1.30至4.29）、三品种杂交犊牛（IRR，4.00；CI，1.93至8.31）或复合品种畜群犊牛（IRR，2.27；CI，1.00至5.16）的养殖场BRDC发病率更高。归类为补充收入来源的养殖场BRDC发病率（IRR，0.48；CI，0.26至0.87）低于归类为主要收入来源的养殖场。报告使用抗菌药物进行饲料补充与BRDC发病率呈正相关（IRR，3.46；CI，1.39至8.60）。报告的平均每月外来人员来访次数也与畜群水平的BRDC发病率显著相关，但影响的大小和方向有所不同。
与断奶前BRDC发病率相关的管理措施可能是母牛-犊牛生产系统中断奶前BRDC发病率的潜在指标或预测因素。
