Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07 Uppsala, Sweden; Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute (SVA), SE-751 89 Uppsala, Sweden.
Section of Animal Health, Växa Sverige, SE-101 24 Stockholm, Sweden.
J Dairy Sci. 2022 Sep;105(9):7764-7772. doi: 10.3168/jds.2021-21390. Epub 2022 Jul 22.
Mycoplasma bovis is an important pathogen causing pneumonia, mastitis, and arthritis in cattle, leading to reduced animal welfare and economic losses worldwide. In this cross-sectional study, we investigated the prevalence of M. bovis in bulk tank milk (BTM) and herd characteristics associated with a positive antibody test result in Swedish dairy herds. Bulk tank milk samples from all Swedish dairy herds (n = 3,144) were collected and analyzed with ID Screen antibody ELISA and PCR. Information on herd characteristics was collected from the national Dairy Herd Improvement database. To identify herd characteristics associated with the presence of antibodies in BTM, logistic regression was used in 4 different models. The apparent herd-level prevalence of M. bovis infection based on antibodies in BTM was 4.8%, with large regional differences ranging from 0 to 20%. None of the BTM samples was positive by PCR. All the antibody-positive herds were situated in the south of Sweden. The logistic regression model showed that larger herds had higher odds of detectable antibodies in BTM (herd size >120 cows, odds ratio = 8.8). An association was also found between antibodies in BTM and both a higher late calf mortality (2-6 mo) and a higher young stock mortality (6-15 mo). This study showed a clear regional difference in the apparent prevalence of M. bovis infection based on antibodies. The relatively low prevalence of M. bovis in Sweden is a strong motivator for the cattle industry to take steps to prevent further spread of the infection. It is essential that the M. bovis status of free herds be known, and the regional differences shown in this study suggest that testing is highly recommended when live cattle from high-prevalence areas are being introduced into herds. We do not recommend using PCR on BTM to detect infected herds, owing to the low detection frequency in this study.
牛支原体是一种重要的病原体，可导致牛的肺炎、乳腺炎和关节炎，导致全球动物福利下降和经济损失。在这项横断面研究中，我们调查了瑞典奶牛场中牛奶中牛支原体的流行情况以及与抗体检测阳性相关的畜群特征。从所有瑞典奶牛场（n=3144）采集牛奶样品，并使用 ID Screen 抗体 ELISA 和 PCR 进行分析。从国家奶牛场改良数据库中收集了畜群特征的信息。为了确定与牛奶中抗体存在相关的畜群特征，我们在 4 个不同模型中使用了逻辑回归。基于牛奶中抗体的牛支原体感染的明显畜群水平流行率为 4.8%，存在从 0 到 20%的大区域差异。没有一个牛奶样本通过 PCR 呈阳性。所有抗体阳性的畜群都位于瑞典南部。逻辑回归模型显示，较大的畜群在牛奶中检测到抗体的可能性更高（畜群规模>120 头奶牛，优势比=8.8）。牛奶中抗体也与晚犊牛死亡率（2-6 月龄）和幼畜死亡率（6-15 月龄）较高有关。本研究表明，基于抗体的牛支原体感染的明显流行率存在明显的区域差异。瑞典牛支原体的相对低流行率是促使奶牛业采取措施防止感染进一步传播的强烈动力。了解自由畜群的牛支原体状态至关重要，本研究显示的区域差异表明，当来自高流行地区的活牛引入畜群时，强烈建议进行检测。由于本研究中检测频率较低，我们不建议使用牛奶 PCR 来检测感染畜群。
