Disease & heat resistance

Heritability of Pulmonary Arterial Pressure and Heart Score in Angus Cattle Adapted to High-Altitude Environments

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Abstract

Beef cattle raised at high altitudes are exposed to chronic hypoxic stress, which can lead to pulmonary hypertension and right-sided heart failure, a condition commonly referred to as High Altitude Disease (HAD; also known as brisket disease). Pulmonary arterial pressure (PAP) is widely used as an indicator of pulmonary hypertension and indicates susceptibility to HAD. Elevated PAP reflects increased pulmonary vascular resistance and compensatory cardiopulmonary responses that can compromise long-term animal health and productivity. Because PAP can be measured in live animals, it represents a practical and informative trait for genetic evaluation and selection in high-altitude production systems. Estimating heritability for PAP is therefore essential for assessing its value as a selection criterion and for guiding breeding strategies aimed at improving cardiopulmonary resilience under hypoxic conditions. To ensure accurate phenotyping, cattle were required to remain at elevation for a minimum of four weeks prior to PAP measurement. Pulmonary arterial pressure records from 37,407 purebred Angus cattle were obtained from the American Angus Association. Measurements were collected via catheterization of the pulmonary artery at weaning under moderate elevation and at yearling age under both moderate and high elevation conditions, with each stage and environment (moderate versus high elevation) treated as a distinct trait in the analyses. Fixed effects for PAP included contemporary group (Herd ID, Process Date, and Lot ID), and age at measurement. The combination of elevation and age classes defined the 3 PAP traits. Additive genetic effects were evaluated using pedigree-based BLUP as well as genomic approaches, including genomic BLUP (GBLUP) and single-step genomic BLUP (ssGBLUP). Heritability estimates for PAP varied across developmental stages, elevation environments, and analytical approaches. Pedigree-based BLUP indicated moderate to high genetic control, with estimates ranging from 0.24 ± 0.03 at weaning to 0.32 ± 0.02 for yearling cattle at moderate elevation and 0.39 ± 0.03 for yearling cattle at high elevation. Incorporation of genomic information altered these estimates: GBLUP yielded higher heritability at weaning (0.39 ± 0.03) but lower values at yearling under moderate (0.42 ± 0.02) and high elevation (0.47 ± 0.02). Heritability estimates from ssGBLUP were intermediate across all stages (0.28 ± 0.02 at weaning, 0.29 ± 0.01 at moderate elevation, and 0.33 ± 0.01 at high elevation), reflecting the integration of pedigree and genomic information. Collectively, these results demonstrate substantial additive genetic variation for PAP and support its use as an effective selection criterion for improving cardiopulmonary resilience in beef cattle managed under hypoxic conditions.

Keywords: 2026

How to Cite:

Alvares, L., Speidel, S., Retallick, K., Garcia, A., Ramos, P. & Enns, M., (2026) “Heritability of Pulmonary Arterial Pressure and Heart Score in Angus Cattle Adapted to High-Altitude Environments”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2285755. doi: https://doi.org/10.31274/wcgalp.23786

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