Rouault Maud, Assié Sébastien, Gausserès Blandine, Meurens François, Foucras Gilles
Oniris, INRAE, BIOEPAR, Nantes, France.
IHAP, Université de Toulouse, INRAE, ENVT, Toulouse, France.
Front Vet Sci. 2025 Jul 9;12:1617061. doi: 10.3389/fvets.2025.1617061. eCollection 2025.
Bovine Respiratory Disease (BRD) is a leading cause of morbidity and mortality in young cattle upon feedlot arrival. The immune response plays a dual role in infection control and lung tissue damage, but few studies have assessed cytokine levels during natural BRD outbreaks. Advances in multiplexed assays now allow for broader cytokine and chemokine profiling in cattle. In this nested case-control study, 184 young bulls from nine French fattening farms were clinically assessed and underwent thoracic ultrasonography (TUS) weekly during the first month on feed. BRD cases ( = 98) and matched healthy controls ( = 86) were selected based on clinical signs. Fifteen cytokines and chemokines were quantified in plasma using a bovine-specific bead-based multiplex assay, on the day an animal was first detected as sick and in its matched control sampled on the same day. BRD-associated pathogens were assessed using qPCR on nasal swabs and paired serology. The link between cytokines and clinical, microbiological, and preconditioning (vaccination and preventive antibiotic treatment) variables was investigated using the Wilcoxon-Mann-Whitney test, mixed-effects linear regression models, and multivariate clustering. Cytokine and chemokine levels did not distinguish clinically sick from healthy animals. No specific cytokine profile was associated with infection by a given pathogen. However, IL-17A and IFN- concentrations were positively associated with treatment relapse and disease severity, suggesting that they may have prognostic potential. Cluster analysis revealed three subgroups with distinct cytokine patterns and health outcomes, in association with preconditioning variables, highlighting the critical role of these interventions in shaping the immune response during BRD outbreaks. This study is the first to report the measurement of such a wide range of cytokines during spontaneous BRD episodes in young bulls. While not diagnostic when considered individually, cytokine profiles may hold prognostic value and could be integrated into multimodal risk stratification tools, in combination with clinical, microbiological data, and TUS results, to improve BRD management in the field. Preconditioning practices, such as vaccination or preventive antibiotic administration, significantly influence early immune responses and should further be investigated to refine prevention strategies and individualize health monitoring protocols at feedlot entry.
牛呼吸道疾病（BRD）是育肥牛进入饲养场后发病和死亡的主要原因。免疫反应在感染控制和肺组织损伤中起双重作用，但很少有研究评估自然BRD暴发期间的细胞因子水平。多重检测技术的进步现在允许对牛进行更广泛的细胞因子和趋化因子分析。在这项嵌套病例对照研究中，对来自九个法国育肥农场的184头年轻公牛进行了临床评估，并在入栏后的第一个月每周进行胸部超声检查（TUS）。根据临床症状选择BRD病例（n = 98）和匹配的健康对照（n = 86）。在动物首次被检测出患病当天及其匹配对照在同一天采样时，使用基于牛特异性微珠的多重检测法对血浆中的15种细胞因子和趋化因子进行定量。使用qPCR对鼻拭子和配对血清学进行BRD相关病原体评估。使用Wilcoxon-Mann-Whitney检验、混合效应线性回归模型和多变量聚类研究细胞因子与临床、微生物学和预处理（疫苗接种和预防性抗生素治疗）变量之间的联系。细胞因子和趋化因子水平无法区分临床患病动物和健康动物。没有特定的细胞因子谱与特定病原体感染相关。然而，IL-17A和IFN-浓度与治疗复发和疾病严重程度呈正相关，表明它们可能具有预后潜力。聚类分析揭示了三个具有不同细胞因子模式和健康结果的亚组，与预处理变量相关，突出了这些干预措施在BRD暴发期间塑造免疫反应中的关键作用。本研究首次报告了在年轻公牛自发BRD发作期间对如此广泛的细胞因子进行测量。虽然单独考虑时不具有诊断性，但细胞因子谱可能具有预后价值，并可与临床、微生物学数据和TUS结果相结合，纳入多模式风险分层工具，以改善现场BRD管理。预处理措施，如疫苗接种或预防性抗生素给药，会显著影响早期免疫反应，应进一步研究以完善预防策略并在育肥牛进入饲养场时个性化健康监测方案。
