Pulmonary arterial pressures, arterial blood-gas tensions, and serum biochemistry of beef calves born and raised at high altitude

Neary, Joseph M.; Garry, Franklyn B.; Holt, Timothy N.; Knight, Anthony; Gould, Douglas; Dargatz, David A.

doi:10.2147/oaap.s45513

Cited by 9 publications

(8 citation statements)

References 20 publications

(16 reference statements)

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“…Previous research conducted on beef calves between 1 and 6 months of age at an altitude of 2,410 m found that provision of oxygen to peripheral tissues was compromised. 6 The results of our study suggest that the same may be true in Holstein dairy calves at moderate altitude. From 5 weeks of age, median L-lactate levels remained over 1.5 mmol/L, indicating substantial anaerobic respiration.…”

Section: Discussionsupporting

confidence: 58%

“…Lack of a hypoxia-induced increase in hematocrit has also been reported in beef calves. 6 Why hematocrit fails to increase is unclear.…”

Section: Discussionmentioning

confidence: 99%

“…[2][3][4][5] A previous study undertaken in beef calves between 1 and 6 months of age at an altitude of over 2,410 m was suggestive of inadequate provision of oxygen to peripheral tissues and poor efficacy of alveolar-arterial oxygen (A-a O 2 ) transfer. 6 A-a O 2 transfer efficacy can be evaluated by estimating the A-a O 2 pressure gradient. Impairment of A-a O 2 transfer is proportional to the A-a O 2 pressure gradient: the higher the A-a O 2 pressure gradient the less oxygen is transferred to the blood for a given ventilation rate.…”

Section: Introductionmentioning

confidence: 99%

“…The goal of this study was to determine whether peripheral oxygen delivery and efficacy of A-a O 2 transfer is compromised in dairy calves at moderate altitude, as it appears to be in beef calves at high altitude. 6 Adequacy of peripheral oxygen delivery was determined by measurement of L-lactate, a product of anaerobic respiration.…”

Section: Introductionmentioning

confidence: 99%

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Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude

Neary¹,

Garry²,

Raabis³

2014

OAAP

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The goal of this study was to determine whether peripheral oxygen delivery and efficacy of alveolar-arterial oxygen (A-a O 2) transfer, as estimated from the A-a O 2 pressure gradient, are compromised in Holstein calves at moderate altitude. The primary objective was to evaluate age-related changes in arterial blood-gas variables, L-lactate, and hematocrit in healthy calves. The secondary objective was to determine if coughing and nasal discharge, commonly used indicators of respiratory disease, are associated with A-a O 2 gradient. Arterial blood-gas tensions were evaluated in a cohort of 61 dairy calves on one farm at moderate altitude (1,601 m to 1,696 m). Sampling was performed on four occasions at approximately 10, 38, 150, and 261 days of age. Hyperventilation, as indicated by hypocapnia, was evident in calves of all ages. Increasing age was associated with a nonlinear increase in arterial oxygen tension (P,0.001) and a nonlinear decrease in A-a O 2 gradient (P,0.001). The mean A-a O 2 gradient at 10 and 38 days of age was over 18 mmHg, indicating poor efficacy of oxygen transfer. Cough score (P=0.02) but not nasal score (P=0.32) was associated with an in increase in A-a O 2 pressure gradient. Mean hematocrit remained low (,27%) despite hypoxemia. From 38 days of age, median L-lactate concentration remained over 1.5 mmol/L, indicating substantial anaerobic respiration due to inadequate oxygen delivery. Twenty-five percent of calves were treated for respiratory disease. The maximum age at first treatment was 102 days. In conclusion, there was a nonlinear improvement in A-a O 2 transfer efficacy with increasing age, but peripheral oxygen delivery remained compromised. Hyperventilation and impaired A-a O 2 transfer due to functional immaturity of the pulmonary system may be risk factors for respiratory disease in dairy calves at moderate altitude.

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Section: Discussionsupporting

confidence: 58%

“…Lack of a hypoxia-induced increase in hematocrit has also been reported in beef calves. 6 Why hematocrit fails to increase is unclear.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude

Neary¹,

Garry²,

Raabis³

2014

OAAP

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“…oxygen tension (McNab, 2002). We recently reported, however, that Angus calves at an altitude of 2,730 m had a hematocrit of just 36% (Neary et al, 2013a), a value comparable to similarly-aged Holstein calves at sea level (Donawick and Baue, 1968;Lumsden et al, 1980). Unfortunately, the majority of prior studies were conducted on a variety of breeds at sea level (Donawick and Baue, 1968;Lekeux et al, 1984;Nagy et al, 2003); consequently, little is known about the effect of altitude on bovine arterial blood-gases and hematocrit.…”

mentioning

confidence: 79%

Angus calves born and raised at high altitude adapt to hypobaric hypoxia by increasing alveolar ventilation rate but not hematocrit1

Gulick

Garry

Holt

et al. 2016

Journal of Animal Science

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The objective of this study was to evaluate the effect of altitude on arterial blood-gases and hematocrit in Angus-based calves. It was hypothesized that alveolar ventilation rate, as indicated by arterial pCO, would increase with altitude but hematocrit would not. Five Angus-based herds ( = 30 to 80 per cohort) located at 105 m, 1,470 m, 2,010 m, 2,170 m, and 2,730 m above sea level were enrolled in this prospective cohort study. A portable analyzer measured blood-gas tensions in coccygeal arterial blood. Calves at 1,470 m, 2,170 m, and 2,730 m were sampled twice, at approximately 4 mo and 7 mo of age. Calves at 105 m and 2,010 m were sampled once, at 7 or 4 mo of age, respectively. Linear regression analyses were used to determine the fixed effect of herd (a proxy for altitude) on the 4 outcome variables pCO, pO, pH, and hematocrit, while controlling for age and sex. As hypothesized, alveolar ventilation rate increased with altitude ( < 0.001). Hematocrit, however, did not show a clear association with altitude except for an increase from 105 m to ≥ 1,470 m ( < 0.001). Arterial pO decreased significantly with increasing altitude in calves at 4 mo and 7 mo of age ( < 0.001). The adjusted mean values of the 4 variables studied were similar at 4 and 7 mo of age for all of the herds studied. This indicates that suckling calves show minimal respiratory or erythrocytic adaptation to hypoxemia and hypocapnia with increasing age, regardless of altitude. We propose that the lack of an erythrocytic response in hypoxemic calves born and raised at high altitude prevents a deleterious increase in viscous resistance and, consequently, pulmonary arterial pressure. This physiological response, or lack thereof, may be a survival adaptation in a species predisposed to hypoxia-induced pulmonary hypertension.

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Relationship of pulmonary arterial pressure and terrain use of Angus cows grazing high-altitude foothill rangelands

et al. 2016

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Pulmonary arterial pressure (PAP) score is used as an indicator trait for risk of 20 hypoxia-induced pulmonary hypertension, which is commonly termed high altitude disease and 21 observed in cattle grazing at altitude ≥ 1500 m. We hypothesized that cows with higher PAP 22 score would avoid using high elevations, steep slopes and areas far from water while grazing 23 foothill rangeland. During 2013 and 2014, forty-one mature Angus cows from a breeding 24 population of cattle selected for tolerance to high altitude were tracked with global positioning 25 system (GPS) collars for 27 and 17 days, respectively. These cows grazed a 1210 ha foothill 26 rangeland pasture with a vertical relief of 2150 to 2411 m. Pulmonary arterial pressure was 27 measured for each animal at 1 year of age (yearling PAP; 38.2 mm Hg ± 5.1 SD mm Hg) and 28 before tracking (mature PAP; 42.6 mm Hg ± 3.7 SD). Yearling PAP score was not correlated 29 with the mature PAP score (r = 0.23, P = 0.15). Terrain use varied among individual tracked 30 cows, and the range among cows within the same pasture was 59 m (2204 m ± 15 SD) for 31 average elevation use, 4.7 percentage points (8.9% ± 0.2 SD) for average slope use and 247 m 32 (446 m ± 77 SD) for average distance from water. No correlation was detected between mature 33 PAP scores and terrain use metrics (mean elevation, slope and distance from water of tracked 34 locations; r = -0.16, 0.24, 0.25; P > 0.10). Similarly, no correlation was detected (P > 0.10) 35between yearling PAP score and terrain use metrics. Yearling and mature PAP scores were not 36 correlated (P > 0.50) to indices of terrain use that combined elevation and slope use (rough 37 index) and elevation, slope and distance from water (rolling index). Yearling PAP and mature 38 PAP were not useful predictors (P > 0.10) of terrain use in multiple regression analyses. Angus 39 cows in this study were apparently adapted to high elevations and PAP score had little, if any, 40 relationship with their metrics of grazing distribution of foothill rangeland. In situations where 41 elevation was higher, terrain was more rugged or cattle were not adapted, results may differ from 42 those observed in this study. 43 44

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Pulmonary arterial pressures, arterial blood-gas tensions, and serum biochemistry of beef calves born and raised at high altitude

Cited by 9 publications

References 20 publications

Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude

Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude

Angus calves born and raised at high altitude adapt to hypobaric hypoxia by increasing alveolar ventilation rate but not hematocrit1

Relationship of pulmonary arterial pressure and terrain use of Angus cows grazing high-altitude foothill rangelands

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