The lungworm Dictyocaulus viviparus can have a major impact on bovine health and productivity. Enzyme-Linked Immunosorbent Assays (ELISA), based on a recombinant Major Sperm Protein (MSP), have been developed to detect D. viviparus-specific antibodies in bulk tank milk (BTM). The objectives of this study are to assess the association between BTM optical density ratio’s (ODR) and farmer-reported lungworm outbreaks based on the clinical sign “coughing” throughout the grazing season and to compare the sensitivity and specificity of two ELISAs under field conditions. The Hannover MSP-ELISA and the prototype Svanova MSP-ELISA were used for the detection of D. viviparus antibodies in BTM samples on 717 dairy farms during the 2018 grazing season. Assuming all herds to be truly lungworm infected, the results show that the Svanova ELISA had a lower sensitivity (40-65%) and specificity (75-90%) for the detection of D. viviparus infections in BTM compared to the Hannover ELISA, which had a sensitivity of 42% and 74% and specificity of 100% and 98% at a cut-off of 0.41 ODR and 0.25 ODR, respectively. Therefore, analyses of the associations between milk antibody levels and farmer-reported outbreaks during the 2018 and 2019 grazing season were assessed using the Hannover ELISA, on 717 and 634 farms, respectively. A positive association was found between a farmer-reported outbreak and having at least two consecutive positive BTM ODR’s at a cut-off of 0.41 in 2018 (Odds Ratio (OR) = 5.5) and 2019 (OR = 2.8). Furthermore, there was a significant association between a farmer-reported outbreak and having a positive BTM ODR in August (OR 2018 = 4.4; OR 2019 = 2.8) and October (OR 2018 = 3.7; OR 2019 = 1.8). On the farms with a farmer-reported outbreak and positive BTM samples, over half (2018 = 77%; 2019 = 57%) of the positive ODR’s were situated before the outbreak and 47% (2018) and 42% (2019) within 12 weeks before the outbreak. In conclusion, there is a positive association between farmer-reported outbreaks and the occurrence of a positive BTM sample at the cut-off of 0.41 ODR using the Hannover ELISA.

蠕虫维氏ic螨可对牛的健康和生产力产生重大影响。已经开发了基于重组主要精子蛋白（MSP）的酶联免疫吸附测定（ELISA），以检测散装罐装牛奶（BTM）中的维氏梭菌特异性抗体。这项研究的目的是根据整个放牧季节的“咳嗽”临床症状，评估BTM光学密度比（ODR）与农民报告的肺炎暴发之间的关联，并比较两种ELISA在田间条件下的敏感性和特异性。汉诺威MSP-ELISA和原型Svanova MSP-ELISA中用于检测的D.胎生2018年放牧季节期间，717家奶牛场的BTM样品中存在抗体。假设所有畜群被真正肺蠕虫感染，结果表明，该Svanova ELISA有用于检测的较低的灵敏度（40-65％）和特异性（75-90％）D.胎生与Hannover ELISA相比，BTM感染的敏感性分别为0.41 ODR和0.25 ODR，灵敏度分别为42％和74％，特异性为100％和98％。因此，分别使用717和634个农场的汉诺威ELISA评估了2018年和2019年放牧季节牛奶抗体水平与农民报告的暴发之间的关联性分析。在一个农民报告的暴发与至少两个连续的BTM ODR阳性之间存在正关联，2018年（几率（OR）= 5.5）和2019年（OR = 2.8）的截止值为0.41。此外，农民报告的暴发与8月（OR 2018 = 4.4; OR 2019 = 2.8）和10月（OR 2018 = 3.7; OR 2019 = 1.8）的BTM ODR呈正相关。在有农民报告的疫情和BTM阳性的农场，超过一半（2018年为77％; 2019年为57％）的ODR位于爆发前，而47％（2018年）和42％（2019年）位于爆发前12周内。总之，在使用汉诺威ELISA进行的农户报告的暴发与ODR截止值为0.41时，BTM阳性样本的发生与正相关。