This research communication reports the results of a study aimed at investigating the effects of introducing Mycobacterium vaccae on paratuberculosis carriage in a dairy herd. M. vaccae is a non-pathogenic member of the Mycobacteriaceae, with immunomodulatory and immunotherapeutic capabilities, acting by stimulating the cellular immune system, important in protection against paratuberculosis. Starting in 2014 we administered, by gavage, 1010 live M. vaccae bacteria to all new-born heifers on a dairy farm, first within 24 h of birth and again 2 weeks later. Paratuberculosis carriage was monitored yearly by milk ELISA. Faecal samples of 50% of cows, aged 3 years, born 1, 2 or 3 years before the experiment's onset, were tested by qPCR for MAP shedding and compared to 100% treated cows of the same age. Within 3 years, milk ELISA positivity was reduced from 6 to 0% and remained unchanged for the subsequent 2 years. One qPCR positive control cow was found each year for a total of 3 animals (2.46%). One positive cow (1%) was found among the treated cows. Two of the 3 positive control animals, still present on the farm at the end of 2019, tested negative whereas the positive test cow continued shedding MAP. M. vaccae shedding heifers mixing with adult cows were the probable means of the microorganism's propagation. The results of this investigation indicate that the introduction of live M. vaccae may be an inexpensive and fast alternative to current paratuberculosis control practices, justifying further exploration of the topic.

中文翻译：

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从百分之六到百分之零鸟分枝杆菌亚种。三年内副结核牛奶 ELISA 阳性——可能是由母牛分枝杆菌诱导的

本研究通讯报告了一项旨在调查引入影响的研究结果母牛分枝杆菌在奶牛群中携带副结核病。母牛分枝杆菌是非致病性成员分枝杆菌科，具有免疫调节和免疫治疗能力，通过刺激细胞免疫系统发挥作用，对预防副结核病很重要。从 2014 年开始，我们通过强饲法管理 1010居住母牛分枝杆菌对奶牛场所有新生小母牛的细菌，首先是在出生后 24 小时内，然后是 2 周后。每年通过牛奶 ELISA 监测副结核病携带情况。50% 的奶牛的粪便样本，年龄为 3 岁，在实验开始前 1、2 或 3 年出生，通过 qPCR 测试了 MAP 脱落，并与 100% 处理过的同龄奶牛进行了比较。在 3 年内，牛奶 ELISA 阳性率从 6% 降至 0%，并在随后的 2 年内保持不变。每年发现一头 qPCR 阳性对照奶牛，共 3 只动物 (2.46%)。在处理过的奶牛中发现了一头阳性奶牛（1%）。到 2019 年底，农场中仍然存在 3 头阳性对照动物中的 2 头，测试结果为阴性，而阳性测试奶牛继续脱落 MAP。母牛分枝杆菌脱落的小母牛与成年母牛混合是微生物繁殖的可能方式。本次调查结果表明，直播母牛分枝杆菌可能是当前副结核病控制实践的一种廉价且快速的替代方案，证明了对该主题的进一步探索。