PAN Livestock Services Ltd., School of Agriculture, Policy and Development, University of Reading, Earley Gate, PO Box 237, Reading, RG6 6EU, UK.
PAN Livestock Services Ltd., School of Agriculture, Policy and Development, University of Reading, Earley Gate, PO Box 237, Reading, RG6 6EU, UK.
Prev Vet Med. 2024 Nov;232:106317. doi: 10.1016/j.prevetmed.2024.106317. Epub 2024 Aug 21.
Effective management of cattle infected with Johne's Disease (JD) is crucial to minimizing transmission and within-herd prevalence. Within Great Britain (GB), the voluntary National Johne's Management Plan (NJMP) requires farmers and a certified vet to conduct a risk assessment to determine the herd risk, examine the herd JD status and formulate a management plan. Individual milk ELISA tests for JD antibodies are widely used to monitor infection. The JD Tracker application, available within the dairy data management software InterHerd+ and other web-based environments, is being used by farmers and veterinarians to facilitate the practical use of milk ELISA data to aid JD-related management decisions. The JD Tracker application uses a herd's milk ELISA data to calculate a collection of 'JD parameters' that are indicative of the current JD status of the herd alongside contemporary and retrospective drivers linked to transmission and maintenance of infection. Herein, we use milk ELISA data from 154 regularly testing herds to review the temporal trends in JD parameters from 2013 to 2022. Since 2015, JD Tracker parameters have improved in these herds, most notably average test value (ATV) and within-herd prevalence (%Pos30). Trends in driver parameters suggest that farmers are progressively less likely to serve repeat test-positive (J5) cows and are more readily removing them. The data also reveal that the burden of JD is disproportionately greater in herds with higher ATV. In 2022, the 25 % of herds with the highest ATVs accounted for 42 % of positive tests and 42 % of repeat ELISA positive (J5) cows. Retrospectively, it is not possible to identify with certainty factors that directly contributed to the trends in JD parameters, but it is notable that the introduction of the NJMP was coincided with the improving JD situation. In 2019, participation in the NJMP or an equivalent scheme became mandatory for dairy farms to be compliant with the food and farms standards assurance scheme Red Tractor, with the result that JD management plans are now completed by 95 % of UK dairy farms. As far as we know, the UK is unique in its development of a tool (the JD Tracker) which adds utility to milk ELISA data using specifically designed JD parameters. Anticipated further work includes the development of a national database of JD testing herds and application of the JD Tracker at national scale to enable more comprehensive industry-level monitoring of JD within GB dairy farms.
有效管理感染了约翰氏病（JD）的牛对于最大限度地减少传播和牛群内的流行至关重要。在大不列颠（GB），自愿的国家约翰氏病管理计划（NJMP）要求农民和认证兽医进行风险评估，以确定牛群的风险，检查牛群的 JD 状况并制定管理计划。个体牛奶 ELISA 检测 JD 抗体被广泛用于监测感染情况。JD Tracker 应用程序可在奶牛数据管理软件 InterHerd+和其他基于网络的环境中使用，农民和兽医使用该应用程序来促进实用化牛奶 ELISA 数据，以辅助 JD 相关的管理决策。JD Tracker 应用程序使用牛群的牛奶 ELISA 数据来计算一组“JD 参数”，这些参数表示牛群当前的 JD 状况以及与传播和维持感染有关的当代和回顾性驱动因素。在此，我们使用来自 154 个定期检测牛群的牛奶 ELISA 数据，回顾了 2013 年至 2022 年 JD 参数的时间趋势。自 2015 年以来，这些牛群的 JD Tracker 参数有所改善，最显著的是平均测试值（ATV）和牛群内的流行率（%Pos30）。驱动因素参数的趋势表明，农民越来越不可能为重复测试阳性（J5）的奶牛提供服务，并且更愿意将其移除。数据还表明，JD 负担在 ATV 较高的牛群中不成比例地更大。2022 年，25%的 ATV 最高的牛群占阳性检测的 42%和重复 ELISA 阳性（J5）奶牛的 42%。回顾性地，不可能确定直接导致 JD 参数趋势的因素，但值得注意的是，NJMP 的引入恰逢 JD 情况的改善。2019 年，为了符合食品和农场标准保证计划 Red Tractor，奶牛场必须参加 NJMP 或等效计划，因此现在英国 95%的奶牛场都完成了 JD 管理计划。据我们所知，英国是独一无二的，它开发了一种工具（JD Tracker），该工具使用专门设计的 JD 参数为牛奶 ELISA 数据增加了实用性。预期的进一步工作包括开发一个全国性的 JD 检测牛群数据库，并在全国范围内应用 JD Tracker，以便在 GB 奶牛场更全面地监测 JD。
