The objective of this study was to estimate true animal-level and herd-level prevalence of Mycobacterium avium subsp. paratuberculosis (MAP) antibodies in Missouri Boer goat herds. Sera harvested from blood samples collected from goats ≥24 months of age in 25 Missouri Boer goat herds were tested for presence of MAP antibodies using a commercial ELISA kit. Herds were declared positive for MAP if one or more goats in the herd tested positive for MAP antibodies. True animal, within-herd, and between-herd prevalences were calculated using the Rogan-Gladen estimator and were 1.4% (95% CI = 0.1 to 3.6%), 3% (95% CI = 0 to 6%), and 54.7% (95% CI = 28.2 to 86.2%), respectively. Findings in this study confirmed that MAP infection is endemic in Missouri Boer goat herds. 1. Introduction Paratuberculosis (PTB) is a progressive, debilitating, and production limiting disease of ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP) infection. Paratuberculosis is recognized worldwide as one of the most economically important food animal diseases affecting cattle, sheep, and goats. Recognized herd losses attributable to PTB include increased mortality and premature culling risks, lower reproductive efficiency, compromised growth rates, and decreased milk yield [1–4]. Although MAP’s zoonotic potential is a subject of debate, [5, 6] the organism’s ability to contaminate milk [7] plus its frequent detection in patients with Crohn’s disease [8, 9] raises concern for a potential public health hazard. Even though goats are considered a minor species in the US, the goat industry is recognized as one of the fastest growing US livestock sectors [10]. However, caprine PTB has not received much attention in the US compared with the degree of attention that bovine PTB has received in recent years. No studies have been conducted to provide valid estimates of prevalence of MAP infection in US goat herds, although a 2009 United States Department of Agriculture Plant and Animal Health Inspection Service (USDA-APHIS) survey revealed that 1.7% of goat operations had reported suspected clinical cases of caprine PTB in 45% of these suspect herds [11]. Thus caprine PTB may be endemic, possibly widespread, and could constitute a serious problem for US goat producers. Valid estimates of prevalence of MAP infection in goats at both the animal and herd level are needed by industry stakeholders to determine whether the disease warrants interventions to mitigate its negative impact on herd profitability. In MAP affected goat herds, possible intervention goals could include
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