Factors associated with bovine tuberculosis in Michigan: Ecological perspectives

Background/Question/Methods Mycobacterium bovis is prevalent in free-ranging white-tailed deer and other species in northeastern Michigan. Free-ranging deer can be reservoir hosts of the disease and sources of interspecies exposure for cattle. While many cattle farms, both dairy and beef, have cattle with Bovine TB positive, other cattle farms that have managed to avoid transmission of Bovine TB to their cattle. In this research, the objective is to examine farmers’ role in ecosystems in which Bovine TB to cattle is transmitted to cattle. The researchers examine factors associated with transmission of Bovine TB in Michigan, with a goal of identifying behavioral and attitudinal conditions that can help cattle farmers successfully protect their cattle from being infected with Bovine TB, avoid feeling humiliated, and allow them to sustain their quality of life. The data of primary interest were collected by a survey instrument. To refine the survey instrument, four focus groups were conducted, with Michigan County Extension Directors, veterinarians and Michigan State University scientists experienced in the epidemiology of Bovine TB. The survey instrument was mailed to farmers in three groups: TB Positive, Matching Control, and TB Free, and 31 useable surveys were returned.

Results/Conclusions Participants’ age ranged from 21 to 84. Of the 31 respondents, 27 identified themselves as farm owners, while others were farm managers or family members of the farm owner. The number of cattle in the farm ranged from 0 to 530. While the number of years the participants were in cattle business ranged from 7 to 72, the number of years cattle have been on their property ranged from 3 to 126. Several between-group differences were identified. Farmers in the bovine TB positive area were more likely to report that a private hunt club/camp nearby than were their counterparts in the bovine TB free area, but not those in the Matching Control group. Respondents in the Matching Control Group were more likely to agree or strongly agree with “keeping wild animals other than deer off their farms”, and with “preventing fence-line contact with wild animals”, than were their counterparts in the Bovine TB Positive Group or Bovine TB Free Group. It may be that strong beliefs were preventive of bovine TB transmission and helped farmers in the Matching Control Group prevent cattle from infection with bovine TB.