A variety of biological materials are suitable for the analysis of bovine DNA. The objective of this study was to evaluate the ease of collection, storage, and cost as well as quality and quantity of DNA samples obtained from Bos taurus (European cattle) and Bos grunniens (yak) using 2 different sample types: whole blood sampling and nasal swabs. Hair follicle DNA samples from yaks were also analyzed. Deoxyribonucleic acid samples were collected from 1 herd of Black Angus yearling bulls (n = 166) and 1 herd of yaks (n = 24). A NanoDrop Bioanalyzer ND1000 was used to quantify DNA. To assess DNA purity, absorbance ratios were determined at wavelengths of 260 nm relative to 280 nm and 260 nm relative to 230 nm. Single nucleotide polymorphism genotyping was performed using a competitive allele-specific PCR (KASP) genotyping system and the call rates to 3 specific SNP were compared. Using a commercially available nonautomated ethanol DNA extraction technique, nasal swabs yielded a greater quantity of DNA than blood (P < 0.0001) and a greater quality DNA sample than blood (P < 0.0001). Blood and nasal swab performance in SNP genotyping assays were similar (P = 0.5). The greater expense of nasal swabs was offset by their ease of use: less time, skill, and equipment was needed to obtain a sample and the storage of samples was more convenient (room temperature). In yaks, accessing the coccygeal vein, which is relatively straightforward in cattle, was difficult. Nasal swabbing and hair follicle sampling in yaks was performed relatively easily. Yak hair follicles were a poor source of DNA. In conclusion, DNA collection using nasal swabs was more convenient and provided a greater quantity of DNA and better quality sample than blood collection in both Angus and yak. Notably, yak hair was a poor source of DNA, and yak blood was difficult to obtain.

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The purposes of this study were to evaluate mean, systolic, and diastolic pulmonary arterial pressures; pulmonary arterial pulse pressures; and systemic oxygen extraction fraction as risk factors for the survival of suckling calves on one ranch located at an altitude of ≥ 2,730 m in Colorado, USA. A prospective cohort study of 58 calves was performed. Pulmonary arterial pressures and systemic oxygen extraction were measured when calves were approximately 3 mo (86 ± 7 d) and 7 mo (197 ± 6 d) of age. Seven of the 58 calves (12%), 4 steers and 3 heifers, were unaccounted for and presumed dead between 3 and 7 mo of age. Calves presumed to have died between 3 and 7 mo of age had significantly greater mean ( = 0.005) and systolic ( = 0.001) pulmonary arterial pressures and greater pulse pressures ( = 0.03) at 3 mo of age than calves that survived to 7 mo. Calves presumed to have died tended to have greater systemic oxygen extraction fractions at 3 mo of age than calves that survived ( = 0.13). Diastolic pressure was not associated with survival ( = 0.27). Mean pulmonary arterial pressure is predominantly determined by static resistance attributable to distal pulmonary arterial remodeling. Pulse pressure and systolic pulmonary arterial pressure represents the dynamic or oscillatory resistance and is determined by the characteristics of ventricular ejection and proximal arterial stiffness. These findings indicate that it may be beneficial to include pressure measurements indicative of both static and dynamic pulmonary arterial resistance in the selection of breeding stock at high altitude.

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Pulmonary hypertension is a noninfectious disease of cattle at altitudes &gt; 1524 m (5,000 ft). Mean pulmonary arterial pressures (PAP) are used as an indicator for pulmonary hypertension in cattle. High PAP cattle (≥ 50 mmHg) entering the feedlot at moderate elevations have lower feed efficiency as compared to low PAP cattle (&lt; 50 mmHg). The impact of pulmonary arterial pressure on mitochondrial function, oxidative phosphorylation (OXPHOS) protein abundance, and meat color was examined using longissimus lumborum (LL) from high (98 ± 13 mmHg; n = 5) and low (41 ± 3 mmHg; n = 6) PAP fattened Angus steers (live weight of 588 ± 38 kg) during early postmortem period (2 h and 48 h) and retail display (day 1 to 9), respectively. High PAP muscle had greater (P = 0.013) OXPHOS-linked respiration and proton leak-associated respiration than low PAP muscles at 2 h postmortem but rapidly declined to be similar (P = 0.145) to low PAP muscle by 48 h postmortem. OXPHOS protein expression was higher (P = 0.045) in low PAP than high PAP muscle. During retail display, redness, chroma, hue, ratio of reflectance at 630 nm and 580 nm, and metmyoglobin reducing activity decreased faster (P &lt; 0.05) in high PAP steaks than low PAP. Lipid oxidation significantly increased (P &lt; 0.05) in high PAP steaks but not (P &gt; 0.05) in low PAP. The results indicated that high PAP caused a lower OXPHOS efficiency and a greater fuel oxidation rates under conditions of low ATP demand in premortem beef LL muscle, this could explain the lower feed efficiency in high PAP feedlot cattle compared to low PAP counterparts. Mitochondrial integral function (membrane integrity or/and protein function) declined faster in high PAP than low PAP muscle at early postmortem. LL steaks from high PAP animals had lower color stability than those from the low PAP animals during simulated retail display, which could be partially attributed to the loss of muscle mitochondrial function at early postmortem by ROS damage in high PAP muscle. Pulmonary arterial hypertension could also decrease type I/type II muscle fiber ratio in skeletal muscle, which needs to be investigated further.