Faculty Publications

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Open Access
Age-related changes in arterial blood-gas variables in Holstein calves at moderate altitude
(Colorado State University. Libraries, 2014-05-15) Neary, Joseph M., author; Garry, Franklyn B., author; Raabis, Sarah M., author; Dove Medical Press Ltd., publisher
The goal of this study was to determine whether peripheral oxygen delivery and efficacy of alveolar-arterial oxygen (A-a O2) transfer, as estimated from the A-a O2 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 O2 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 O2 gradient (P<0.001). The mean A-a O2 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 O2 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 O2 transfer efficacy with increasing age, but peripheral oxygen delivery remained compromised. Hyperventilation and impaired A-a O2 transfer due to functional immaturity of the pulmonary system may be risk factors for respiratory disease in dairy calves at moderate altitude.
Open Access
Evaluation of a novel canine activity monitor for at-home physical activity analysis
(Colorado State University. Libraries, 2015) Yashari, Jonathan M., author; Duncan, Colleen G., author; Duerr, Felix M., author; BioMed Central, publisher
Background: Accelerometers are motion-sensing devices that have been used to assess physical activity in dogs. However, the lack of a user-friendly, inexpensive accelerometer has hindered the widespread use of this objective outcome measure in veterinary research. Recently, a smartphone-based, affordable activity monitor (Whistle) has become available for measurement of at-home physical activity in dogs. The aim of this research was to evaluate this novel accelerometer. Eleven large breed, privately owned dogs wore a collar fitted with both the Whistle device and a previously validated accelerometer-based activity monitor (Actical) for a 24-h time period. Owners were asked to have their dogs resume normal daily activities. Total activity time obtained from the Whistle device in minutes was compared to the total activity count from the Actical device. Activity intensity from the Whistle device was calculated manually from screenshots of the activity bars displayed in the smartphone-application and compared to the activity count recorded by the Actical in the same 3-min time period. Results: A total of 3740 time points were compared. There was a strong correlation between activity intensity of both devices for individual time points (Pearson's correlation coefficient 0.81, p < 0.0001). An even stronger correlation was observed between the total activity data between the two devices (Pearson's correlation coefficient 0.925, p < 0.0001).Conclusions: Activity data provided by the Whistle activity monitor may be used as an objective outcome measurement in dogs. The total activity time provided by the Whistle application offers an inexpensive method for obtaining at-home, canine, real-time physical activity data. Limitations of the Whistle device include the limited battery life, the need for manual derivation of activity intensity data and data transfer, and the requirement of Wi-Fi and Bluetooth availability for data transmission.
Open Access
Pulmonary arterial pressures, arterial blood-gas tensions, and serum biochemistry of beef calves born and raised at high altitude
(Colorado State University. Libraries, 2013-07-15) Neary, Joseph M., author; Garry, Franklyn B., author; Holt, Timothy N., author; Knight, Anthony P., author; Gould, Daniel H., author; Dargatz, David A., author; Dove Medical Press Ltd., publisher
High-altitude exposure is physiologically challenging. This is particularly true for animals native to low-altitude environments, such as British breeds of cattle. The objective of this study was to document the effect of high altitude on select physiological parameters of healthy beef calves (Bos taurus) born and raised on a high-altitude ranch typical of the Rocky Mountain region. Pulmonary arterial pressures, arterial blood-gas tensions, serum biochemistry, and hematocrit were evaluated. The calves studied were a composite of British (50%-75%) and Continental (25-50%) breeds born on one ranch at an altitude of 2410 m. Calves were sampled at an altitude of 2410 m when 1 month old and again at an altitude of 2730 m when 3 and 6 months old. Between 3 and 6 months of age, calves had access to grazing from 2730 m to approximately 3500 m above sea level. On each occasion, 16 to 50 calves were sampled. Only calves that remained healthy throughout all three testing periods were included in the dataset. Calves with the highest pulmonary arterial pressures at 1 month of age tended to have the highest pressures at 6 months of age (r = 0.43, P = 0.16, n = 12). Respiratory alkalosis was greatest at 6 months of age (pH 7.48 ± 0.06). Mean alveolar-arterial oxygen pressure gradients were 11.7and 11.6 mmHg at 3 and 6 months of age, indicating poor transfer of oxygen from the alveoli into the pulmonary blood. Median values for blood lactate ranged from 1.4 to 3.4 mmol/L indicating substantial anaerobic respiration at all ages. Mean hematocrits were ≤ 35.7%, only slightly higher than values obtained from age-matched calves at sea level. These results suggest that the provision of oxygen to the peripheral tissues of beef calves may be compromised at altitudes over 2410 m. This may have implications for diseases of the cardiopulmonary system.
Open Access
The method of attachment influences accelerometer-based activity data in dogs
(Colorado State University. Libraries, 2017-02-10) Martin, Kyle W., author; Olsen, Anastasia M., author; Duncan, Colleen G., author; Duerr, Felix M., author; BioMed Central, publisher
Background: Accelerometer-based activity monitoring is a promising new tool in veterinary medicine used to objectively assess activity levels in dogs. To date, it is unknown how device orientation, attachment method, and attachment of a leash to the collar holding an accelerometer affect canine activity data. It was our goal to evaluate whether attachment methods of accelerometers affect activity counts. Eight healthy, client-owned dogs were fitted with two identical neck collars to which two identical activity monitors were attached using six different methods of attachment. These methods of attachment evaluated the use of a protective case, positioning of the activity monitor and the tightness of attachment of the accelerometer. Lastly, the effect of leash attachment to the collar was evaluated. For trials where the effect of leash attachment to the collar was not being studied, the leash was attached to a harness. Activity data obtained from separate monitors within a given experiment were compared using Pearson correlation coefficients and across all experiments using the Kruskal-Wallis Test. Results: There was excellent correlation and low variability between activity monitors on separate collars when the leash was attached to a harness, regardless of their relative positions. There was good correlation when activity monitors were placed on the same collar regardless of orientation. There were poor correlations between activity monitors in three experiments: when the leash was fastened to the collar that held an activity monitor, when one activity monitor was housed in the protective casing, and when one activity monitor was loosely zip-tied to the collar rather than threaded on using the provided metal loop. Follow-up, pair-wise comparisons identified the correlation associated with these three methods of attachment to be statistically different from the level of correlation when monitors were placed on separate collars. Conclusions: While accelerometer-based activity monitors are useful tools to objectively assess physical activity in dogs, care must be taken when choosing a method to attach the device. The attachment of the activity monitor to the collar should utilize a second, dedicated collar that is not used for leash attachment and the attachment method should remain consistent throughout a study period.

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