Bovine tuberculosis has substantial impact on fertility, milk and meat productivity in cattle. However, these assumptions are based on outdated data. Recent global studies on the impact of BTB on cattle productivity are scarce, and show sometimes inconclusive and/or contradicting results. This pilot study is the first longitudinal study performed in urban upgraded dairy cattle in Ethiopia that are kept under intensive husbandry. We assessed whether BTB has an impact on various animal productivity parameters and animal movement. Animals (N=890) included in the study were tested for BTB at least once using the comparative intradermal tuberculin test (CIDT). Fertility, mortality and offtake were assessed in 21 dairy farms where herd follow-ups over three years were performed. In addition, an independent abattoir survey was conducted to assess carcass weight and visible TB-like lesions upon meat inspection. Animal movements (purchasing and offtakes) were documented for each farm. The impact of bTB status on the intervals been birth, service and calving times and the intercalving intervals were analysed using a Cox proportional hazards model. The hazard ratio associated with BTB positive animals was smaller than 1 for all fertility parameters, suggesting that BTB status increases the time between events, however the effect was small and only statistically significant (95% level) for the time between calving and service. Offtakes included a higher percentage of reactor animals (58%) as compared to non-reactor animals (42%) (p=0.0001). Overall, reactors were eliminated from the farms within 238.6 days after receiving test results, which was 54.9 days faster than for negative animals. The majority of owners purchased animals within their town or its surrounding. Nearly a quarter of reactors were sold directly to other farms. Animals were also sold further away, including other regions raising the question of disease spread and the need for an animal tracing mechanism. In the abattoir survey, a total of 349 carcasses were weighed, of which 8% showed visible TB-like lesions and 53.6% had fasciolosis. Negative adult bull carcasses were 7.5kg heavier than reactor bulls.

中文翻译：

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牛结核病对埃塞俄比亚中部集约化饲养的奶牛的选定生产力参数和贸易的影响


牛结核病对牛的生育力、产奶量和产肉量有重大影响。然而，这些假设是基于过时的数据。最近关于 BTB 对牛生产力影响的全球研究很少，并且有时显示出不确定和/或矛盾的结果。这项试点研究是对埃塞俄比亚城市集约化饲养的奶牛进行的第一项纵向研究。我们评估了 BTB 是否对各种动物生产力参数和动物运动有影响。使用比较皮内结核菌素试验 (CIDT) 对研究中的动物 (N=890) 进行至少一次 BTB 检测。对 21 个奶牛场的生育率、死亡率和采食量进行了评估，并对牛群进行了三年多的跟踪调查。此外，还进行了一项独立屠宰场调查，以评估屠体重量和肉品检查时可见的结核样病变。每个农场的动物流动（采购和销售）都有记录。使用 Cox 比例风险模型分析了 bTB 状态对出生、配种和产犊时间间隔以及产犊间隔的影响。对于所有生育参数，与 BTB 阳性动物相关的风险比均小于 1，这表明 BTB 状态增加了事件之间的时间，但影响很小，并且仅对于产犊和配种之间的时间具有统计显着性（95% 水平）。与非反应堆动物 (42%) 相比，反应堆动物的排放量 (58%) 更高 (p=0.0001)。总体而言，在收到检测结果后 238.6 天内，反应堆就被从农场中淘汰，这比阴性动物快了 54.9 天。大多数业主在他们的城镇或其周边地区购买动物。 近四分之一的反应堆直接出售给其他农场。动物也被卖到更远的地方，包括其他地区，这引发了疾病传播的问题以及动物追踪机制的必要性。在屠宰场调查中，总共对349头尸体进行了称重，其中8%显示出可见的结核样病变，53.6%患有片形吸虫病。阴性成年公牛尸体比反应堆公牛重 7.5 公斤。