Instituto de Medicina Preventiva Veterinaria, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile.
Instituto de Medicina Preventiva Veterinaria, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile.
Prev Vet Med. 2020 Mar;176:104888. doi: 10.1016/j.prevetmed.2020.104888. Epub 2020 Jan 9.
The study objective was to identify risk factors associated to: i) the infection by Mycobacterium avium subsp. paratuberculosis (MAP), and ii) paratuberculosis clinical incidence in Chilean dairy herds. A random sample of forty herds with previous history of MAP infection was selected. At herd level, all lactating cows were tested using a commercial ELISA kit. On the sampling date, a questionnaire gathering information on herd demographics, husbandry practices, and biosecurity measures was applied. Additionally, the farm manager/owner was surveyed regarding the number of paratuberculosis compatible clinical cases (CCC) in the last 12 months. Two Bayesian generalized linear mixed effect models were used to evaluate the association between the questionnaire data, and the proportion of truly infected animals (model 1) or the number of CCC (model 2). A total of 4963 animals were sampled with an average apparent prevalence of 6.3 % (95 % confidence interval (4.0-8.0%). All sampled herds presented seropositive animals. Forty eight percent of the herds did not observe any CCC in the last year. Although, among those herd that did report CCC, a median of two cases per year was estimated. Model outputs showed that the proportion of truly infected animals and CCC reporting rates are associated to management practices. Specifically, positive associations were observed for feeding of calves exclusively with milk replacer, and the distance between the milking parlor and the calves' barn. Additionally, CCC reporting rates were higher in farms that recently purchased animals, and where the distance between the milking parlor and the calves' barn was less than 30 m.
i）感染禽分枝杆菌副结核亚种（MAP），以及 ii）智利奶牛场副结核病的临床发病情况。选择了具有 MAP 感染既往史的四十个随机牧场进行抽样。在牧场层面，所有泌乳奶牛均使用商业 ELISA 试剂盒进行检测。在采样日，应用问卷调查收集牧场人口统计学、饲养管理和生物安全措施方面的信息。此外，还对农场经理/所有者进行了调查，询问过去 12 个月中副结核病符合临床病例（CCC）的数量。使用两个贝叶斯广义线性混合效应模型来评估问卷调查数据与真正感染动物的比例（模型 1）或 CCC 数量（模型 2）之间的关联。共对 4963 只动物进行了采样，平均表观流行率为 6.3%（95%置信区间为 4.0-8.0%）。所有抽样牧场的动物均呈现血清阳性。48%的牧场在过去一年中没有观察到任何 CCC。然而，在报告 CCC 的牧场中，估计每年有中位数为 2 例。模型输出表明，真正感染动物的比例和 CCC 报告率与管理实践相关。具体而言，仅用代乳料喂养小牛和挤奶厅与小牛畜栏之间的距离与这两个指标呈正相关。此外，在最近购买动物且挤奶厅与小牛畜栏之间的距离小于 30m 的农场中，CCC 报告率更高。
