Author
Snowder, Gary | |
Van Vleck, Lloyd | |
Cundiff, Larry | |
Bennett, Gary |
Submitted to: World Congress of Genetics Applied in Livestock Production
Publication Type: Proceedings Publication Acceptance Date: 3/1/2006 Publication Date: 8/1/2006 Citation: Snowder, G.D., Van Vleck, L.D., Cundiff, L.V., Bennett, G.L. 2006. Genetic parameters for respiratory disease in feedlot beef cattle. Proceedings 8th World Congress of Genetics Applied in Livestock Production. CD-ROM Communication No. 15-14. Belo Horizonte, Brazil. Interpretive Summary: Bovine respiratory disease (BRD) is the most common and costly disease of feedlot cattle in the United States. However, it is not known if genetic factors influence the incidence of BRD. Therefore, the objective of this study was to characterize genetic factors that influence incidence of BRD in feedlot beef calves. Growth and health records of 18,112 cattle from nine purebreds (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite breeds (MARC I, MARC II, and MARC III) were analyzed. Records spanned a 15 year period (1987 to 2001). Estimates of heritability for resistance to BRD ranged from 0.04 to 0.08 ± 0.01. When the observed heritability based on a dichotomous trait was transformed to an underlying continuous normal scale which representative of the true nature of disease resistance, the adjusted heritability estimate was 0.18. This low heritability infers that response to direct selection for resistance to BRD using field records will be slow. Technical Abstract: The objective of this study was to characterize genetic factors that influence incidence of bovine respiratory disease (BRD) in feedlot beef calves. Growth and health records of 18,112 cattle from nine purebreds (Angus, Braunvieh, Charolais, Gelbvieh, Hereford, Limousin, Pinzgauer, Red Poll, and Simmental) and three composite breeds (MARC I, MARC II, and MARC III) were analyzed. Records spanned a 15 year period (1987 to 2001). Because not all breeds were present for each of the 15 years, the data set was partitioned into 3 additional data sets for proper tests of contrasts among breeds Estimates of heritability for resistance to BRD were estimated using MTDFREML and ranged from 0.04 to 0.08 ± 0.01. Heritability for resistance to BRD on an underlying continuous normal scale was estimated to be 0.18. |