Bovine tuberculosis slaughter surveillance in the United States: assessment of its trace-back function 2001-2010
Date
2012
Authors
Mann, Heather, author
Olea-Popelka, Francisco, advisor
Orloski, Kathleen, committee member
Salman, Mo, committee member
Basaraba, Randall, committee member
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Abstract
The detection of gross bovine tuberculosis (bovine TB) lesions in cattle at slaughter and the successful trace-back to the herd of origin is critical to the detection of infected herds and for the progress of the national bovine TB eradication program in the United States (U.S.). A national animal identification system to identify and trace individual animals is currently under development in the U.S.; however, it is not yet fully implemented. In order to quantify the impact slaughter surveillance and traceability of bovine TB infected cattle has on the eradication of bovine TB from the cattle population in the U.S., this study was conducted with the aim to determine the ability of the current bovine TB slaughter surveillance system to trace infected cattle back to the herd of origin. Data obtained for the period 2001-2010, in which 386 bovine lesions were confirmed as bovine TB in the U.S., were used for this study. The specific objectives for this study were 1) to review and document the available literature related to the history of bovine TB control in the U.S., focusing primarily on the current method of disease detection (slaughter surveillance) and the impediments to eradication in the U.S., 2) to quantify the number of successful trace-backs of bovine TB infected animals to their herd of origin during 2001-2010 3) to quantify the number of trace-backs that found at least one bovine TB infected ("affected") herd, and 4) determine if selected factors were associated with the probability of successfully tracing infected animals and finding infected herds. The results of this study indicates that the odds of successful trace-backs are 7.06 times greater for cattle with official identification than without official identification (OR 95% CI: 1.66, 29.93, p-value =0.008). Additionally, the odds of successful trace-back are 15.47 times greater for adult cattle compared to fed cattle (OR 95% CI: 4.47, 53.48, p-value<0.001). Thus, application of official ID on all classes of cattle would increase the probability of successfully tracing bovine TB cases back to a herd of origin; however, under the current system it will not ensure a complete success in tracing bovine TB infected cattle to the herd of origin. While adult cattle are currently more likely to be traced back than fed cattle, it is worth noting that the effort and time required to find the herd of origin for both adult and fed bovine TB cases can be substantial and is highly variable. The results of this study provide an important tool to aid U.S. officials in their decision making with respect to the evaluation and implementation of strategies for the national bovine TB control and eradication program.
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Subject
animal sciences
epidemiology
trace-back
United States
bovine tuberculosis
cattle