Department of Ecosystem and Public Health, University of Calgary, Calgary, AB, Canada T2N 4N1.
Business Economics Group, Wageningen University, Wageningen 6706 KN, the Netherlands.
J Dairy Sci. 2019 Mar;102(3):2578-2592. doi: 10.3168/jds.2018-15341. Epub 2019 Jan 11.
Bovine leukemia virus (BLV) is a production-limiting disease common in North American dairy herds. To make evidence-based recommendations to Canadian dairy producers and their consultants regarding cost and financial benefits of BLV on-farm control, an economic model that takes the supply-managed milk quota system into account is necessary. Alberta-specific input variables were used for the presented analysis. A decision tree model program was used to evaluate economic aspects of decreasing a 40% BLV within-herd prevalence on dairy farms by implementing various control strategies over 10 yr. Investigated strategies were (1) all management strategies, including 3 options for colostrum management; (2) some management strategies; (3) test and cull; and (4) test and segregate. Each of these strategies was compared with a no control on-farm approach. The prevalence for this no-control approach was assumed to stay constant over time. Each control strategy incurred specific yearly cost and yielded yearly decreases in prevalence, thereby affecting yearly partial net revenue. Infection with BLV was assumed to decrease milk production, decrease cow longevity, and increase condemnation of carcasses at slaughter from cattle with enzootic bovine leukosis, thereby decreasing net revenue. Cows infected with BLV generated a yearly mean partial net revenue of Can$7,641, whereas noninfected cows generated Can$8,276. Mean cost for the control strategies ranged from Can$193 to Can$847 per animal over 10 yr in a 146-animal herd. Net benefits of controlling BLV on farm, as compared with not controlling BLV, per cow in a 146-animal herd over a 10-yr period for each strategy was: Can$1,315 for all management strategies (freezer); Can$1,243 for all management strategies (pasteurizer); Can$785 for all management strategies (powdered colostrum); Can$1,028 for some management strategies; Can$1,592 for test and cull; and Can$1,594 for test and segregate. Consequently, on-farm BLV control was financially beneficial. Even though negative net benefits were possible and expected for some iterations, our sensitivity analysis highlighted the overall robustness of our model. In summary, this model provided evidence that Canadian dairy farmers should be encouraged to control BLV on their farm.
牛白血病病毒（BLV）是北美奶牛群中常见的一种生产限制疾病。为了向加拿大奶农及其顾问提出有关 BLV 农场控制的成本和财务效益的循证建议，有必要建立一个考虑到供应管理牛奶配额制度的经济模型。本分析使用了艾伯塔省特定的投入变量。使用决策树模型程序来评估通过在 10 年内实施各种控制策略降低奶牛场 40%BLV 场内流行率的经济方面。研究的策略包括：（1）所有管理策略，包括 3 种初乳管理选项；（2）一些管理策略；（3）检测和淘汰；以及（4）检测和隔离。与无农场控制方法相比，这些策略中的每一种都进行了比较。假设这种无控制的方法在一段时间内保持不变。每种控制策略都会产生特定的年度成本，并导致年度流行率下降，从而影响年度部分净收入。BLV 感染被假设会降低牛奶产量、降低奶牛寿命，并增加因地方性牛白血病而被屠宰的牛的胴体淘汰，从而降低净收入。感染 BLV 的奶牛每年的部分净收入平均为 7641 加元，而非感染奶牛的部分净收入为 8276 加元。在一个 146 头奶牛的畜群中，10 年内控制策略的平均成本为每头动物 193 至 847 加元。在 10 年内，与不控制 BLV 相比，每个策略在一个 146 头奶牛的畜群中每头牛的农场 BLV 控制净收益为：所有管理策略（冷冻）为 1315 加元；所有管理策略（巴氏消毒）为 1243 加元；所有管理策略（粉状初乳）为 785 加元；一些管理策略为 1028 加元；检测和淘汰为 1592 加元；检测和隔离为 1594 加元。因此，农场 BLV 控制具有财务效益。尽管在某些迭代中可能会出现负的净收益并且预计会出现负的净收益，但我们的敏感性分析突出了我们模型的整体稳健性。总之，该模型提供了证据表明，加拿大奶农应该被鼓励在其农场控制 BLV。
