Beef cattle residing >1,500 m are subject to reduced atmospheric oxygen levels when compared with beef cattle at lower elevations which may result in hypoxia-induced pulmonary hypertension and right-side heart failure. Breeders use pulmonary arterial pressures to identify animals at risk of right-side heart failure and to select breeding animals that are less susceptible to the problem. There is a concern that selection for growth and carcass characteristics may be increasing the incidence of heart failure in feedlot cattle at elevations <1,500 m. To address the concern, this study estimated the genetic correlations (i.e., relationships) between pulmonary arterial pressure, growth, and ultrasound carcass measures in Angus cattle. The study shows that the genetic relationships between pulmonary arterial pressure and these traits are minimal to non-existent with the exception of ultrasound ribeye area. Our estimate suggests a moderate, unfavorable relationship between pulmonary arterial pressure and ribeye area and that single-trait selection for increased ribeye area alone may result in increased susceptibility to right-side heart failure. However, selection for both traits simultaneously should overcome increases in susceptibility given the moderate strength of the genetic relationship.

Read the full article in the Journal of Animal Science.