The use of pulmonary arterial pressure for improved beef cattle mangement by modeling relationships with pulmonary arterial pressure and performance, maternal, and carcass traits

Abstract

Pulmonary arterial pressure (PAP) determines an animal's susceptibility to High Altitude Disease (HAD) which causes pulmonary hypertension due to hypoxia. It is estimated that 1.5 million head of cattle are raised in high altitude environments (above 1500 m) and HAD accounts for 3-5% of calf death loss yearly. Study 1 modeled the relationship of PAP estimates with gestation length, birth weight, and grow traits of developing bulls. Additionally, it compared mean PAP scores of the most common sire and grandsire lines from progeny within the data set. Study 2 modeled the relationship of PAP estimates with production, maternal, and carcass expected progeny differences (EPDs). For both studies, bull PAP estimates were collected from Angus yearling bulls ranging in age from 5400 12-18-month-old bulls from 2016-2023 from a Montana-based Angus operation. In study 1, increased gestation lengths showed increased PAP scores (P < 0.01). Bulls with greater birth weight had greater PAP scores (P < 0.01). There was no observed relationship between bull PAP and weaning weight (P = 0.26). Additionally, PAP was negatively correlated to yearling weight (P = 0.04). Bulls with greater birth-to-weaning gains had decreased PAP scores (P = 0.05). Increased weaning-to-yearling gains had lower PAP scores (P = 0.02). Greater birth-to-yearling growth had lower PAP scores (P < 0.01). Sire lines influenced offspring PAP scores (P < 0.01), and dam sire lines tended to have on effect offspring PAP scores (P = 0.09). In study 2, bulls with greater calving ease direct had lower PAP scores (P < 0.01). Bulls with greater birth weight EPDs had increased PAP scores (P < 0.01). The weaning weight EPD was positively correlated to PAP scores (P < 0.01). Increased yearling weight EPDs had greater PAP scores (P < 0.01). Bulls with greater PAP had increased carcass weight EPDs (P = 0.03). There were no observed relationships (P ? 0.17) between bull PAP and scrotal circumference, maternal milk, ribeye area, or marbling EPDs. In summary, PAP was related to many performance traits and production EPDs, however these relationships explain very little of the variation is PAP estimates.