Abstract
Johne's disease (JD or paratuberculosis) control programs have been established in many dairy-producing regions. However, the effectiveness (reduction of within-herd prevalence) and the relative economic impact as measured by, for example, the ratio of benefits to costs (BCR) across a comprehensive selection of regions and potential control practices require further investigation. Within a Markovian framework using region-specific economic variables, it was estimated that vaccination was the most promising type of JD control practice modeled, with dual-effect vaccines (reducing shedding and providing protective immunity) having BCRs between 1.48 and 2.13 in Canada, with a break-even period of between 6.17 and 7.61 years. Dual-effect vaccines were also estimated to yield BCRs greater than one in almost all major dairy-producing regions, with greater ratios in regions characterized by above-average farm-gate prices and annual production per cow. Testing and culling was comparably effective to a dual-effect vaccine at test sensitivities >70% but would remain economically unviable in almost all regions modeled.
Highlights
Johne’s disease (JD), or paratuberculosis, is an infectious chronic inflammatory disorder of the intestines that can affect domestic and wild ruminants including dairy cattle [1]
The proportional changes in within-herd prevalence from its initial mean value of 10% based on 10,000-iteration simulations of the various control practices are presented in Figure 1 and Table 1
The greatest decreases relative to no intervention were observed in the scenarios of dualeffect vaccination, testing and culling combined with protective immunity vaccination, and testing and culling combined with dual-effect vaccination
Summary
Johne’s disease (JD), or paratuberculosis, is an infectious chronic inflammatory disorder of the intestines that can affect domestic and wild ruminants including dairy cattle [1]. As the infection progresses in cattle, the clinical effects worsen in severity from diarrhea and reduced milk production to lethargy, hypoproteinemia, and severe emaciation [5]. These clinical effects result in substantial economic losses for dairy producers [6], with decreased milk production [7, 8], decreased slaughter value [9,10,11], and premature culling [12, 13] among the primary sources of losses. It has been estimated that an average benefit of US$8.03 per animal per year is associated with vaccination
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