Submitted to: International Conference on Mycobacterium bovis
Publication Type: Abstract Only
Publication Acceptance Date: 8/13/2000
Publication Date: N/A
Technical Abstract: Bovine tuberculosis has been confirmed in 6 herds of cattle in Michigan where the disease has become established in free-ranging white-tailed deer. The purpose of this study was to determine if cattle can become infected with Mycobacterium bovis through indirect contact with experimentally infected white-tailed deer. Twelve deer were inoculated by the intratonsilar route with 7 x 105 M. bovis. After 2 weeks, 9 six-month old calves were introduced into the barn. Each group of deer (3 groups of 4 deer) was paired with a group of calves (3 groups of 3 calves). Deer were given excess feed and allowed access to it overnight. Deer were then moved to a holding pen and the calves were moved to the previous deer pen, which was not cleaned. Pens previously occupied by the calves were cleaned before moving the deer into them. This process was repeated daily for 80 days. All of the calves were classified as reactors to the CCT on day 77. Results of the BOVIGAM assay were positive for 3 calves on day 28 and were positive for all 9 calves on day 56. Gross and microscopic lesions were observed and M. bovis was isolated from all calves when necropsied beginning on day 177. All calves had lesions in the lung or associated lymph nodes and 1 calf had lesions in the medial retropharyngeal lymph node. Results of this study show that calves can become infected with M. bovis through indirect contact with experimentally infected white-tailed deer.