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The eradication of bovine tuberculosis (bTB), caused by Mycobacterium bovis , from cattle in many locations worldwide is complicated by endemic foci of the disease in free-ranging wildlife. Recent simulation modeling of the bTB outbreak in white-tailed deer (WTD) in Michigan, USA, suggests current management is unlikely to eradicate bTB from the core outbreak area (DMU 452) within the next three decades. However, some level of control short of eradication might sufficiently reduce transmission from deer to cattle to a point at which the negative effects of bTB on the cattle industry could be reduced or eliminated, while minimizing the negative consequences of reducing deer numbers. We extended our existing spatially-explicit, individual-based stochastic simulation model of bTB transmission in WTD to incorporate transmission to cattle, to characterize the effects of vaccination and increased harvest of WTD on cattle herd breakdown rates, to examine the effects of localized culling or vaccination of WTD in the vicinity of cattle farms, to assess the effects of concurrent deer baiting, and to determine the effect of progressive restriction of deer/cattle contact on herd breakdowns. A spatially-explicit “cattle layer” was constructed describing the spatial locations, farm size and cattle density of all farms within and directly adjacent to DMU452. Increased hunter harvest or vaccination of deer, or a combination, would likely decrease the number of cattle herd breakdowns to <1 per year in less than 15 years. Concurrent deer baiting variably increased the time necessary to achieve zero breakdowns. The prevalence of bTB in deer needed to fall below ∼0.5% before ≤1 herd breakdown per year could be expected, and below 0.1% before zero breakdowns were likely. Locally applied post-harvest deer culling or vaccination also rapidly reduced herd breakdowns. On farm biosecurity measures needed to reduce deer to cattle contact by >95% in order to reliably reduce herd breakdowns, and did not achieve zero breakdowns in the absence of other deer controls. [ABSTRACT FROM AUTHOR]

ABSTRACT Bovine tuberculosis (bTB) caused by Mycobacterium bovis infection in Michigan white-tailed deer ( Odocoileus virginianus) has proven resistant to current management practices. The Michigan Department of Natural Resources (MDNR) is faced with managing a protracted bTB outbreak with shrinking economic resources, its initial control strategies approaching, or having reached, the limits of their effectiveness. Planning tools are needed to project the outbreak's future course and forecast the likely outcomes of proposed controls. We describe development of a spatially explicit, individual-based stochastic simulation model of bTB in Michigan white-tailed deer. We sought to 1) characterize whether eradication of bTB is possible by increasing hunter harvest or via vaccination, and how long it is likely to take to achieve eradication; 2) characterize the effect of concurrent deer baiting; and 3) assess the effect of baiting on the probability of bTB establishment in uninfected areas. Simulations indicated that current MDNR management strategies are unlikely to eradicate bTB from the core outbreak area's deer population within the next 30 years. A 50-100% increase (over current rates) of both antlered and antlerless deer harvest was required to achieve eradication if baiting was occurring, compared to only a 50% increase in harvest required if baiting was eliminated. Vaccination strategies required frequent application and high exposure rates (>90%) to achieve eradication, which baiting delayed. Simulations indicated that if bTB was eradicated from the core outbreak area, a single infected deer introduced into the area would be 8 times more likely to re-establish bTB if baiting was occurring. The ability to forecast likely outcomes of disease management can be critical for wildlife managers to assess whether specific strategies are likely to be successful. Because current policy appears unlikely to achieve the stated goal of eradicating bTB from Michigan in the foreseeable future, reorienting the bTB program from eradication to controlling geographic spread and transmission to cattle may be more realistic goals. Spatial models such as ours are ideally suited to investigating spatial heterogeneity of disease transmission, and how transmission is influenced by aggregating factors such as baiting or supplemental feeding. © 2014 The Wildlife Society. [ABSTRACT FROM AUTHOR]

Objective: To determine the incidence of ocular abnormalities in miniature horses., Design: Descriptive study., Animals Studied: Fifty-three miniature horses., Procedure: Ophthalmic examinations were performed using diffuse and focal illumination, slit-lamp biomicroscopy and indirect ophthalmoscopy. Coat color, mane and tail color, age and gender were recorded with results of ophthalmic examination., Results: Ocular abnormalities detected most frequently consisted of cysts arising from the posterior iris, ciliary body, and peripheral retina, curvilinear streaks of retinal pigmented epithelium extending from the peripheral temporal retina, and retinal dysplasia (folds). One miniature horse also had multiple ocular abnormalities (cornea globosa, goniosynechiae, decreased or absent and pupillary light reflexes, miotic and dyscoric pupils, iris hypoplasia, and epinuclear cataract). Ocular abnormalities were observed in horses that had a flaxen or white mane and tail color and a chocolate coat color., Conclusions: Abnormal ocular phenotype detected in eyes of Miniature Horses was similar to multiple congenital and hereditary ocular abnormalities reported in the Rocky Mountain Horse. Phenotypic ocular developmental abnormalities and coat, mane and tail color were most compatible with a heterozygous or homozygous effect of the Silver Dapple locus., (© 2011 American College of Veterinary Ophthalmologists.)