Department of Agricultural and Applied Economics, University of Wyoming, 1000 E. University Avenue, Dept. 3354, Laramie, WY 82071, USA.
Prev Vet Med. 2012 Dec 1;107(3-4):187-203. doi: 10.1016/j.prevetmed.2012.06.008. Epub 2012 Jul 12.
Cattle in the Greater Yellowstone Ecosystem occasionally contract bovine brucellosis from free-ranging elk and bison. Cattle producers use a variety of brucellosis prevention activities to reduce their herds' risk of contracting brucellosis, such as: (1) having state agency personnel haze elk off private land, (2) fencing haystacks, (3) administering adult booster vaccination, (4) spaying heifers, (5) altering the winter-feeding schedule of cattle, (6) hiring riders to prevent cattle-elk commingling, and (7) delaying grazing on high-risk allotments. Their brucellosis prevention decisions are complicated, however, by several sources of uncertainty, including the following: a cattle herd's baseline risk of contracting brucellosis, the inherent randomness of brucellosis outbreaks, the cost of implementing prevention activities, and the activities' effectiveness. This study eliminates one source of uncertainty by estimating the cost of implementing brucellosis prevention activities on a representative cow/calf-long yearling operation in the southern GYE. It then reports the minimum level of effectiveness each prevention activity must achieve to justify investment by a risk-neutral producer. Individual producers face different levels of baseline risk, however, and the US government's brucellosis-response policy is constantly evolving. We therefore estimate breakeven levels of effectiveness for a range of baseline risks and government policies. Producers, animal health experts, and policymakers can use this study's results to determine which brucellosis prevention activities are unlikely to generate sufficient expected benefits to cover their cost of implementation. Results also demonstrate the influence of government policy on producers' incentives to prevent brucellosis. Policies that increase the magnitude of economic loss a producer incurs when their herd contracts brucellosis subsequently decrease prevention activities' breakeven levels of effectiveness, and increase producers' incentives to implement those activities. Producers' incentives to implement prevention activities also increase as activities' costs decrease. Policymakers can easily adapt the results of this analysis to help target cost-share agreements to producers and prevention activities most likely to generate positive expected net benefits. Epidemiologists can also use our results to help prioritize future research on the technical effectiveness of various brucellosis prevention activities.
大黄石生态系统中的牛偶尔会从自由放养的麋鹿和野牛身上感染牛布鲁氏菌病。牛养殖户使用各种布鲁氏菌病预防措施来降低其牛群感染布鲁氏菌病的风险，例如：（1）让州机构人员驱散私人土地上的麋鹿，（2）围起干草堆，（3）给成年牛接种加强疫苗，（4）给小母牛去势，（5）改变牛的冬季饲养时间表，（6）雇佣骑手防止牛和麋鹿混群，以及（7）延迟在高风险分配地放牧。然而，他们的布鲁氏菌病预防决策受到多种不确定性因素的影响，包括以下几个方面：牛群感染布鲁氏菌病的基线风险、布鲁氏菌病暴发的固有随机性、实施预防措施的成本，以及这些措施的有效性。本研究通过估算在大黄石生态系统南部的一个具有代表性的奶牛/小牛-一年生牛群的养殖场实施布鲁氏菌病预防措施的成本，消除了一个不确定性因素。然后，它报告了每种预防措施必须达到的最低有效性水平，以证明风险中立的养殖户进行投资是合理的。然而，个别养殖户面临着不同的基线风险，并且美国政府的布鲁氏菌病应对政策也在不断演变。因此，我们估算了一系列基线风险和政府政策下的盈亏平衡有效性水平。养殖户、动物健康专家和政策制定者可以使用本研究的结果来确定哪些布鲁氏菌病预防措施不太可能产生足够的预期收益来覆盖其实施成本。结果还表明了政府政策对养殖户预防布鲁氏菌病的激励的影响。当养殖户的牛群感染布鲁氏菌病时，政府政策增加了养殖户的经济损失规模，从而降低了预防措施的盈亏平衡有效性水平，并增加了养殖户实施这些措施的动力。随着预防措施成本的降低，养殖户实施预防措施的动力也会增加。政策制定者可以轻松地调整本分析的结果，以帮助将成本分担协议针对最有可能产生正预期净收益的养殖户和预防措施。流行病学家也可以使用我们的结果来帮助确定未来针对各种布鲁氏菌病预防措施的技术有效性的研究重点。
