Characterizing and managing bovine tuberculosis transmission risk between white-tailed deer and beef cattle through indirect contact at hay bales

Risks associated with bovine tuberculosis (Mycobacterium bovis) between wildlife and livestock are significant for conservation. White-tailed deer (deer; Odocoileus virginianus) winter hay bale damage data collected by... [ view full abstract ]

Risks associated with bovine tuberculosis (Mycobacterium bovis) between wildlife and livestock are significant for conservation. White-tailed deer (deer; Odocoileus virginianus) winter hay bale damage data collected by Manitoba Agricultural Services Corporation between 1996 and 2008 within areas of 7,205km² around Riding Mountain National Park and 6,742km² around Duck Mountain Provincial Forest accumulated to $658,443. Indirect bovine tuberculosis transmission risk from deer to cattle can threaten Canada’s international beef markets. Bovine Tuberculosis holds global significance, impacting human and wildlife health from North America to Europe, Africa and Australia. Objectives were to (1) quantify environmental variables that predict deer hay bale use (using Resource Selection Probability Function), (2) determine deer damage trends, (3) test if hay yard barrier fences around Riding Mountain National Park significantly reduced deer hay bale damage, and (4) review mitigation options. Annual damage frequency did not significantly decrease around Riding Mountain National Park (R²= 0.016; df = 11, P= 0.685) or Duck Mountain Provincial Forest (R²= 0.007; df = 11, P= 0.785). Using Resource Selection Probability Function, predictive models of damage and bovine tuberculosis transmission risk through damage were generated with good validity (AUC= 0.763, z= 9.642, p <0.0001). Damage risk was widespread within the study area. Resource Selection Probability Function results indicated deer selected agricultural land farther from Riding Mountain National Park and Duck Mountain Provincial Forest than elk (Cervus canadensis). Risk of bovine tuberculosis transmission among deer and livestock was highest in Northwest Riding Mountain National Park surrounding regions. Mitigation options include using Resource Selection Probability Function risk maps to prioritize hay yard barrier fence expansion and implementing hunting to reduce older male deer populations with higher bovine tuberculosis prevalence. Practical application includes producer or government use of Resource Selection Probability Function risk maps to focus mitigation, reducing costs by targeting actions on highest risk areas.