Thesis (Ph. D.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on June 29, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Animal Science, Department of Agricultural, Food and Nutritional Science, University of Alberta." Includes bibliographical references.

Bovine viral diarrhea (BVD) is an economically important disease of cattle. Calves persistently infected (PI) with the bovine viral diarrhea virus (BVDV) are a powerful agent for spread of the virus. A total of 24,423 southeast origin beef cattle comingled at three Warren County, Kentucky locations were tested from November 2007 to June 2010 for PI BVDV. A total of 97 head tested positive for PI BVDV, giving an average overall prevalence of 0.397%. Calves tested were subdivided into categories for additional calculations of dependence. A total of 8,910 were categorized by weight range upon testing (300-399 lbs, 400-499 lbs, 500-599 lbs, and 600-699 lbs). Prevalence does show a dependence on weight, with a higher prevalence found in lower weight classes, especially 300-399 lb calves (P<0.001). A total of 24,423 were categorized by season at time of testing (Fall, Winter, Spring, Summer). Prevalence does not show a dependence on season (P>0.05). Although eradication programs are not likely to be organized in the United States, several control programs have been developed. These findings can be used as additional support for PI testing of calves, especially those in lighter weight classes, as part of a BVD control program.

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