Smith R L, Al-Mamun M A, Gröhn Y T
Department of Pathobiology, University of Illinois, College of Veterinary Medicine, Urbana, IL 61802, USA.
Department of Population Medicine and Diagnostic Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY 14850, USA.
Prev Vet Med. 2017 Mar 1;138:17-27. doi: 10.1016/j.prevetmed.2017.01.007. Epub 2017 Jan 10.
The cost of paratuberculosis to dairy herds, through decreased milk production, early culling, and poor reproductive performance, has been well-studied. The benefit of control programs, however, has been debated. A recent stochastic compartmental model for paratuberculosis transmission in US dairy herds was modified to predict herd net present value (NPV) over 25 years in herds of 100 and 1000 dairy cattle with endemic paratuberculosis at initial prevalence of 10% and 20%. Control programs were designed by combining 5 tests (none, fecal culture, ELISA, PCR, or calf testing), 3 test-related culling strategies (all test-positive, high-positive, or repeated positive), 2 test frequencies (annual and biannual), 3 hygiene levels (standard, moderate, or improved), and 2 cessation decisions (testing ceased after 5 negative whole-herd tests or testing continued). Stochastic dominance was determined for each herd scenario; no control program was fully dominant for maximizing herd NPV in any scenario. Use of the ELISA test was generally preferred in all scenarios, but no paratuberculosis control was highly preferred for the small herd with 10% initial prevalence and was frequently preferred in other herd scenarios. Based on their effect on paratuberculosis alone, hygiene improvements were not found to be as cost-effective as test-and-cull strategies in most circumstances. Global sensitivity analysis found that economic parameters, such as the price of milk, had more influence on NPV than control program-related parameters. We conclude that paratuberculosis control can be cost effective, and multiple control programs can be applied for equivalent economic results.
通过牛奶产量下降、提前淘汰和繁殖性能不佳，副结核病给奶牛群造成的成本已得到充分研究。然而，控制计划的益处一直存在争议。最近对美国奶牛群中副结核病传播的随机分区模型进行了修改，以预测初始患病率为10%和20%的100头和1000头奶牛的牛群在25年内的净现值（NPV）。控制计划是通过结合5种检测方法（无检测、粪便培养、酶联免疫吸附测定、聚合酶链反应或犊牛检测）、3种与检测相关的淘汰策略（所有检测呈阳性、高阳性或反复阳性）、2种检测频率（每年和每两年一次）、3种卫生水平（标准、中等或改善）以及2种停止检测决策（在5次全群检测呈阴性后停止检测或继续检测）来设计的。确定了每种牛群情况的随机优势；在任何情况下，没有一个控制计划在使牛群NPV最大化方面完全占优势。在所有情况下，通常都首选使用酶联免疫吸附测定检测，但对于初始患病率为10%的小牛群，没有高度首选的副结核病控制措施，而在其他牛群情况下则经常被首选。基于它们对副结核病的单独影响，在大多数情况下，改善卫生状况不如检测和淘汰策略具有成本效益。全局敏感性分析发现，经济参数，如牛奶价格，对NPV的影响比与控制计划相关的参数更大。我们得出结论，副结核病控制可能具有成本效益，并且可以应用多种控制计划以获得等效的经济结果。
