Evaluating the genetic relationship between high elevation pulmonary arterial pressure and moderate elevation feedlot performance and carcass traits
Date
2020
Authors
Briggs, Emma, author
Speidel, Scott E., advisor
Enns, R. Mark, advisor
Thomas, Milt G., committee member
Holt, Tim, committee member
Journal Title
Journal ISSN
Volume Title
Abstract
The objective of the study was to evaluate if a genetic relationship exists between post weaning pulmonary arterial pressure (PAP) measured at high elevation and traits associated with moderate elevation feedlot performance and carcass traits. For this study, PAP (collected 1992-2018; n = 6,898), feedlot performance (2014-2018; n = 558), and carcass data (2001-2018; n = 1627) were obtained from the Colorado State University Beef Improvement Center Angus herd. At an elevation of 2,115 m, post weaning, PAP measurements were collected; subsequently, a selected group of steers were relocated to a moderate elevation feedlot (1,500 m) where feedlot performance data was collected. Genetic relationships were evaluated with a series of 5-trait models using REML statistical approaches. Traits in this analysis were assigned contemporary groups, fixed effects and a direct genetic random effect. A maternal additive and permanent environmental effect was included to weaning weight in the analysis. The heritability estimate for PAP was 0.20 ± 0.03. Genetic correlations between PAP and feedlot traits were positive, with estimates of 0.32 ± 0.20 (average dry matter intake) and 0.03 ± 0.17 (average daily gain). The strongest genetic correlation between PAP and carcass performance traits were those of rib eye area (-0.30 ± 0.12) and calculated yield grade (0.29 ± 0.12). Genetic correlations between PAP and marbling score, back fat, or hot carcass weight were 0.00 ± 0.13, -0.07 ± 0.13, and 0.14 ± 0.10, respectfully. These results suggest a favorable genetic relationship exists between PAP and feedlot and carcass traits. As cattle with lower post-weaning PAP move to lower elevation feedlot, they could potently have heavier muscled carcasses compared to their high PAP contemporaries.