Characterizing the impact of altitude and finishing system on mean pulmonary arterial pressure and carcass characteristics in Angus cattle

摘要

High mountain disease (HMD) is a cardiopulmonary condition observed in cattle grazing at elevations greater than 1,500 m ( ). The condition is characterized as the progression of pulmonary hypertension resulting from chronic exposure to environmental hypoxia at high altitude ( ). Cattle intolerant of these hypoxic conditions often undergo pulmonary vascular remodeling, pulmonary hypertension, cardiopulmonary insufficiencies, right heart failure, and death. HMD affects 3% to 5% of cattle at high altitude on average, but some ranchers have reported death losses as great as 25% ( ; , ; ).