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United States Department of Agriculture

Agricultural Research Service

Title: Bovine Respiratory Disease in Feedlot Cattle: I. Environmental, Genetic and Economic Factors

Authors
item Snowder, Gary
item Van Vleck, Lloyd
item Cundiff, Larry
item Bennett, Gary

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 27, 2006
Publication Date: July 1, 2006
Citation: Snowder, G.D., Van Vleck, L.D., Cundiff, L.V., Bennett, G.L. 2006. Bovine respiratory disease in feedlot cattle: Environmental, genetic and economic factors. Journal of Animal Science 84(8):1999-2008.

Interpretive Summary: Bovine respiratory disease (BRD) is the most costly disease of feedlot cattle in the United States. Our objective was to characterize genetic, environmental and economic factors related to BRD in feedlot cattle. Records from nine breeds (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite types (MARC I, MARC II, and MARC III) over a 15 yr period (1987 to 2001) were evaluated. The incidence of BRD varied across years, with annual observed incidence ranging from 5 to 44%. The epidemiological pattern indicated that BRD infection increased dramatically after 5 d on feed and remained high until approximately 80 d on feed. Previous BRD infection during the preweaning period did not influence subsequent BRD infection in the feedlot. Steers were more likely to become sick with BRD than heifers; castration prior to entry in the feedlot is a suspected predisposing cause. Few significant differences among breeds for BRD incidence were detected. Herefords were generally more susceptible than MARC I and III composite types to BRD infection. Crossbred cattle had similar susceptibility compared to other purebred breeds. Death loss associated with BRD was highest in Red Poll calves (9%) compared to an average over all breeds of 4%. Estimates of heritability for resistance to BRD ranged from 0.04 to 0.08 ± 0.01. Selection for resistance to BRD could be effective if phenotypes for BRD resistance were known. Thus, development of an inexpensive and humane method of challenging animals with BRD to determine resistance would be an important step in reducing incidence of BRD. The economic loss associated with BRD infection in a 1,000 cattle feedlot was estimated at $13.90 per animal, not including labor and associated handling costs.

Technical Abstract: The objective of this study was to characterize genetic, environmental and economic factors related to the incidence of bovine respiratory disease (BRD) in feedlot calves. Records from 18,112 calves representing nine breeds (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite types (MARC I, MARC II, and MARC III) over a 15 yr period (1987 to 2001) were evaluated. Disease incidence was observed and recorded by station veterinarian and technical staff. The incidence of BRD varied across years, with annual observed incidence ranging from 5 to 44%. From 1987 to 1992, annual average incidence generally exceeded 20%. However, in later years annual incidence did not exceed 14%. The epidemiological pattern indicated that BRD infection increased dramatically after 5 d on feed and remained high until approximately 80 d on feed. Previous BRD infection during the preweaning period did not influence subsequent BRD infection in the feedlot. Steers were more likely to become sick with BRD than heifers; castration prior to entry in the feedlot may be a suspected predisposing cause. Few significant differences among breeds for BRD incidence were detected. Adjusted solutions from mixed model analyses indicated that Herefords were generally more susceptible than MARC I and III composite types to BRD infection. Composite breeds had similar susceptibility compared to other purebred breeds. Mortality associated with BRD was highest in Red Poll calves (9%) compared to an average over all breeds of 4%. Estimates of heritability for resistance to BRD ranged from 0.04 to 0.08 ± 0.01. When the observed heritability was transformed to an underlying continuous scale, the estimate increased to 0.18. Selection for resistance to BRD could be effective if phenotypes for BRD resistance were known. Thus, development of an inexpensive and humane method of challenging animals with BRD to determine resistance would be an important step in reducing incidence of BRD. This study also demonstrated that producer collected field data could be used for selection against this disease. The economic loss associated with BRD infection in a 1,000 cattle feedlot was estimated at $13.90 per animal, not including labor and associated handling costs.

Last Modified: 4/19/2014
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