Mycoplasma bovis is an important cause of pneumonia and mastitis in cattle throughout the world, often reported as emerging. In absence of an effective vaccine for M. bovis, current prevention and control strategies rely on the identification of risk factors for within- and between-herd spread. The objective of this study was to determine the prevalence of M. bovis in Belgian dairy herds and to identify risk factors associated with a positive PCR or antibody ELISA bulk tank milk (BTM) test. A cross-sectional study was performed in 2016 on 100 dairy farms, analyzing BTM using PCR and antibody ELISA. Information on herd-level risk factors focusing on biosecurity and management were collected through a questionnaire and sourced from the national herd identification system (SANITRACE, Animal Health Service Flanders). Multivariable logistic regression was used to identify herd-level risk factors for the presence of M. bovis DNA and antibodies in BTM. The apparent prevalence on BTM was 7 and 17% for PCR and antibody ELISA, respectively. The true prevalence was 7.1% [95% confidence interval (CI) = 2.1–11.5%] and 24.8% (95% CI = 16.4–33.2%). There was no overlap between ELISA- and PCR-positive farms, resulting in a combined true prevalence of 31.8% of the Belgian farms being in recent contact with M. bovis. Risk factor analysis showed that herds with a breeding bull [M. bovis-positive results for 45.5 and 13.6% of herds with and without a bull, respectively, odds ratio = 4.7 (95% CI = 1.1–19.8)] and without a calving pen [M. bovis-positive result in 52.4 and 20.6% of the herds without and with a calving pen, respectively, odds ratio = 3.7 (95% CI = 1.06–12.5)] had higher odds to harbor M. bovis antigen or antibodies in BTM. In conclusion, the present study points to a several fold increase in the prevalence of M. bovis in Belgian dairy herds. The importance of the breeding bull and calving pen in the between- and within-herd spread of M. bovis might have been underestimated in the past. Focusing on these factors might contribute to more effective control programs in the future.

牛支原体是全世界牛的肺炎和乳腺炎的重要病因，据报道经常是新兴病。在没有针对牛分枝杆菌的有效疫苗的情况下，当前的预防和控制策略依赖于确定牛群内和牛群间传播的危险因素。这项研究的目的是确定比利时乳牛群中牛分枝杆菌的流行情况，并确定与阳性PCR相关的危险因素或抗体ELISA散装牛奶（BTM）测试。2016年对100个奶牛场进行了横断面研究，使用PCR和抗体ELISA分析BTM。通过问卷调查收集了有关以生物安全和管理为重点的牛群风险因素的信息，并从国家牛群识别系统（SANITRACE，动物健康服务法兰德斯）获得了信息。多变量logistic回归用于确定牛分枝杆菌存在的牛群风险因素BTM中的DNA和抗体。PCR和抗体ELISA在BTM上的明显患病率分别为7％和17％。真实患病率是7.1％[95％置信区间（CI）= 2.1-11.5％]和​​24.8％（95％CI = 16.4-33.2％）。ELISA和PCR阳性养殖场之间没有重叠，因此，最近与牛分枝杆菌接触的比利时养殖场的合并真实患病率为31.8％。风险因素分析表明，具有繁殖公牛的牛群[牛分枝杆菌阳性结果，有和没有公牛的牛群分别为45.5和13.6％，优势比= 4.7（95％CI = 1.1-19.8）]，并且没有产犊。钢笔[ M. bovis-阳性结果分别有52.4和20.6％的牛群使用和不使用产犊笔，比值比= 3.7（95％CI = 1.06–12.5）]在BTM中具有牛分枝杆菌抗原或抗体的几率更高。总之，本研究表明比利时乳牛群中牛分枝杆菌的患病率增加了几倍。过去可能低估了繁殖牛和产犊笔在牛分枝杆菌之间和群内传播的重要性。关注这些因素可能会在将来有助于更有效的控制程序。