[Pulmonary function testing in the cat - an overview]. / Lungenfunktionsmessung bei der Katze ­ eine Übersicht.

This article provides an overview of currently available pulmonary function tests in cats, divided into invasive and non-invasive methods. Invasive techniques comprise arterial blood gas analysis and measurement of pulmonary mechanics. Non-invasive techniques include pulse oximetry and capnography, as well as methods not yet integrated into everyday practice such as tidal breathing airflow-volume loops, whole-body barometric plethysmography and thorax compression. In this article, the background, execution, interpretation, and limitations of each test are discussed. Proper performance and assessment of pulmonary function measurements may aid in understanding the pathophysiology of feline respiratory disease and in increasing objectivity when assessing the existing disease and treatment efficacy.

Ontogenesis of evolved changes in respiratory physiology in deer mice native to high altitude.

High-altitude environments are cold and hypoxic, and many high-altitude natives have evolved changes in respiratory physiology that improve O2 uptake in hypoxia as adults. Altricial mammals undergo a dramatic metabolic transition from ectothermy to endothermy in early post-natal life, which may influence the ontogenetic development of respiratory traits at high altitude. We examined the developmental changes in respiratory and haematological traits in deer mice (Peromyscus maniculatus) native to high altitude, comparing the respiratory responses to progressive hypoxia between highland and lowland deer mice. Among adults, highlanders exhibited higher total ventilation and a more effective breathing pattern (relatively deeper tidal volumes), for mice that were caught and tested at their native altitudes and those lab-raised in normoxia. Lab-raised progeny of each population were also tested at post-natal day (P)7, 14, 21 and 30. Highlanders developed an enhanced hypoxic ventilatory response by P21, concurrent with the full maturation of the carotid bodies, and their more effective breathing pattern arose by P14; these ages correspond to critical benchmarks in the full development of homeothermy in highlanders. However, highlanders exhibited developmental delays in ventilatory sensitivity to hypoxia, hyperplasia of type I cells in the carotid body and increases in blood haemoglobin content compared with lowland mice. Nevertheless, highlanders maintained consistently higher arterial O2 saturation in hypoxia across development, in association with increases in blood-O2 affinity that were apparent from birth. We conclude that evolved changes in respiratory physiology in high-altitude deer mice become expressed in association with the post-natal development of endothermy.

Clinical Application of Pulmonary Function Testing in Small Animals.

Pulmonary function tests (PFTs) are important diagnostic tools that have wide clinical applications in human and veterinary medicine. Widespread use of PFTs in measuring lung volumes in veterinary medicine was historically limited by the need for specialized equipment to accurately perform and interpret these tests, and by lack of patient cooperation. However, recent advances and modifications have allowed PFTs to be safely performed in conscious veterinary patients with minimal stress. This article focuses on the most commonly used tests of pulmonary function including tests of pulmonary mechanics and of gas exchange in the lungs.

Randomised study of the immunomodulatory effects of azithromycin in severely asthmatic horses.

Neutrophilic inflammation is believed to contribute to the airway obstruction and remodelling in equine asthma. Azithromycin, an antibiotic with immunomodulatory properties, reduces pulmonary neutrophilia and hyper-responsiveness in human asthmatics and decreases airway remodelling in rodent models of asthma. It was therefore hypothesised that azithromycin would improve lung function, mucus accumulation and central airway remodelling by decreasing luminal neutrophilia in severe equine asthma. The effects of a 10-day treatment with either azithromycin or ceftiofur, an antimicrobial without immune-modulating activity, were assessed using a blind, randomised, crossover design with six severe asthmatic horses in clinical exacerbation. Lung function, tracheal mucus accumulation, tracheal wash bacteriology, bronchial remodelling, airway neutrophilia and mRNA expression of proinflammatory cytokines (interleukin (IL)-8, IL-17A, IL-1ß, tumour necrosis factor-α) in bronchoalveolar lavage fluid were evaluated. Azithromycin decreased the expression of IL-8 (P=0.03, one-tailed) and IL-1ß (P=0.047, one-tailed) but failed to improve the other variables evaluated. Ceftiofur had no effect on any parameter. The reduction of neutrophilic chemoattractants (IL-8, IL-1ß) justifies further efforts to investigate the effects of a prolonged treatment with macrolides on airway neutrophilia and remodelling. The lack of efficacy of ceftiofur suggests that severe equine asthma should not be treated with antibiotics at first-line therapy.

The relationship between bronchoalveolar lavage fluid cytology and airway hyper-reactivity in a population of Australian horses presented for poor performance.

OBJECTIVE: To investigate the relationship between bronchoalveolar lavage fluid cytology, particularly mast cells, and airway hyper-reactivity in athletic horses presented for poor performance that included a respiratory tract evaluation in two disparate locations in Australia. DESIGN: Multi-centre, retrospective and prospective cross-sectional study METHODS: Eighty four adult horses underwent both pulmonary function testing and histamine bronchoprovocation with a commercial flowmetric plethysmography system. A bronchoalveolar lavage was performed four to twelve hours later. Bronchoalveolar lavage fluid cytology was categorised using two differing classification systems to define mild equine asthma. Statistical analysis was used to assess associations between bronchoalveolar lavage fluid relative inflammatory cell percentages, and airway hyper-reactivity and their associated categorisations. RESULTS: Sixty four percent (54/84) of horses displayed airway hyper-reactivity, as defined by PC35 < 6 mg/ml of histamine. A relative mastocytosis was the most common bronchoalveolar lavage fluid cytological abnormality. Horses with a sole mast cell response of ≥ 5% within their bronchoalveolar lavage fluid displayed airway hyper-reactivity at a lower dose of nebulized histamine than horses with normal bronchoalveolar lavage fluid cytology. Horses with mixed cell responses (relative mast cell percentage > 2% and/or relative neutrophil percentage > 5% and/or eosinophil relative cell percentage ≥ 1%) displayed airway hyper-reactivity at a lower dose of nebulized histamine than horses with normal bronchoalveolar lavage fluid cytology. CONCLUSION: In the Australian context, recently revised increased bronchoalveolar lavage fluid cytology relative cell percentage cut offs appear appropriate for sole mast cell responses. The historical lower cut offs appear to be appropriate for mixed inflammatory cell responses.

Growth of preweaned, group-housed dairy calves diagnosed with respiratory disease using clinical respiratory scoring and thoracic ultrasound-A cohort study.

The objectives of this cohort study were to identify a cut point on a previously described 6-level ultrasound score (USS6) at which average daily gain (ADG) is affected and to determine whether there is any additional benefit of using a clinical respiratory score. Calves from a commercial herd in Ohio were enrolled at entry to an automated calf feeder barn at (mean ± standard deviation) 21 ± 6 d of age (n = 308). Calves that survived until 50 d (n = 233) were included in the analyses. Twice-weekly health exams included a clinical respiratory score (CRS), USS6 (0-5, based on lung mass involved), and body weight. For the CRS, the nose, eyes, ears, cough, and rectal temperature were assigned a score (0-3), and calves were considered positive (CRS+) when at least 2 areas scored ≥2. For analysis, USS6 and CRS status were based on a calf's first bovine respiratory disease event identified during the study period. The first multivariable linear model was fit to determine whether USS6 was associated with ADG and controlled for CRS. We detected no difference in ADG among calves with USS6 scores of 2, 3, 4, and 5. Based on this finding, we proposed a simplified 2-level ultrasound score (USS2; without lung consolidation or with lung consolidation ≥1 cm2). A second multivariable model was fit to assess the association between USS2 and ADG; this model controlled for CRS, birth weight category, breed, and cohort. Calves with lung consolidation (n = 169) had lower ADG than calves without lung consolidation (n = 64; 0.73 vs. 0.85 kg/d, respectively). Calves that were CRS+ (n = 61) had lower ADG than calves that were CRS- (n = 172; 0.74 vs. 0.84 kg/d, respectively). Although CRS did not affect the relationship between USS2 and ADG, both CRS and USS2 are necessary to explain variation in ADG. We simplified USS6 and proposed USS2 based on how lung consolidation affected ADG. A simplified 2-level ultrasound score may be more practical for veterinarians to identify calves that may be at risk for poor growth. The effect on ADG was similar between calves with lung consolidation and calves identified as CRS+. Therefore, both thoracic ultrasonography and CRS should be used to identify calves with all types of respiratory disease that affect growth. However, this study represents calves in group housing from 21 to 50 d of age on 1 farm with high disease incidence. We encourage studies that investigate the effects of lung consolidation and CRS on ADG in different management systems.

Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, Tursiops truncatus.

We measured respiratory flow (V̇), breathing frequency (fR), tidal volume (VT), breath duration and end-expired O2 content in bottlenose dolphins (Tursiops truncatus) before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O2, VT and fR following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering VT and fR to rapidly replenish the O2 stores. For the first breath following a surface breath-hold, the end-expired O2 decreased with dive duration, while VT and fR increased. Throughout the recovery period, end-expired O2 increased while the respiratory effort (VT, fR) decreased. We propose that the dolphins alter respiratory effort following a breath-hold according to the reduction in end-expired O2 levels, allowing almost complete recovery after 1.2 min.

Influence of dexamethasone and surfactant in the vitality and lung function of preterm lambs born by cesarean section / Influência da dexametasona e do surfactante na vitalidade e na função pulmonar de cordeiros prematuros nascidos por cesariana eletiva

The aim of this study was to assess the vitality and lung function of preterm lambs. Twenty seven preterm lambs were divided in four groups. Group I (n=6) preterm lambs/ control; group II (n=9) lambs born to mothers that were treated with dexamethasone antepartum; group III (n=6) lambs treated with surfactant; and group IV (n=6) lambs treated with surfactant and born to mothers that were treated with dexamethasone antepartum. The APGAR score was performed after birth (T0) and 15 minutes later (T1/4) to assess vitality. The vital signs, blood gas analysis, spirometry and capnometry were assessed immediately after birth and continued until 48 hours. Chest radiographs were performed at T0, T24 and T48. Significant rectal temperature interactions occurred at T1 and T6 depending on the type of treatment used. All animals showed low pH values, which were associated with high pCO2 values and HCO3 -values that increased over time from immediately after birth to two days of age. Higher tidal volume values were observed at T1/4, T1 and T24 when the animals were not treated with surfactant. Capnometry showed significant interactions between treatments at T0. Premature animals showed low vitality and impaired pulmonary function.(AU)

O objetivo do presente trabalho foi avaliar a vitalidade e a função pulmonar de cordeiros prematuros. Vinte e sete cordeiros foram divididos em quatro grupos: grupo I (n= 6), cordeiros prematuros/controle; grupo II (n= 9), cordeiros prematuros nascidos de mães tratadas com dexametasona antes do parto; grupo III (n= 6), cordeiros prematuros tratados com surfactante; e grupo IV (n= 6), cordeiros prematuros tratados com surfactante e nascidos de mães tratadas com dexametasona antes do parto. O escore APGAR foi realizado após o nascimento (T0) e 15 minutos depois (T1/4). Os parâmetros vitais, hemogasometria, espirometria e capnometria foram avaliados após o nascimento até 48 horas. As radiografias torácicas foram realizadas em T0, T24 e T48. Interações significativas de temperatura retal ocorreram em T1 e T6, dependendo do tipo de tratamento utilizado. Todos os animais apresentaram valores de pH baixos, que foram associados com altos valores de pCO2 e valores de HCO3 que aumentaram ao longo do tempo. Os maiores valores de volume corrente foram observados em T1/4, T1 e T24, quando os animais não foram tratados com surfactante. A capnometria mostrou interações significativas entre tratamentos em T0. Os animais prematuros apresentaram pouca vitalidade e deficiência da função pulmonar.(AU)

Contribution of lung function tests to the staging of severe equine asthma syndrome in the field.

Staging methods are useful tools for monitoring disease and response to treatment, and because Severe Equine Asthma Syndrome (SEAS) has a high prevalence in the equine population, a clinical staging method can provide important information to optimize equine care. Our team has previously developed and published a clinical staging method for SEAS and in the present study we further evaluated information provided by lung function tests, in order to determine their contribution to disease staging. Using discriminant analysis we set out to produce a new staging method with applicability in the field. Differences between group means (P < .05) were observed for clinical score, bronchoalveolar lavage fluid neutrophil percentage, pleural pressure (ΔPpl), PaO2 and histamine concentration and the linear functions obtained explained 99.3% of the data variability, with 94.7% of cases grouped correctly and a cross-validation of 86.8%. Thus this staging model showed very good results and the discriminant linear functions may be used to identify and stage SEAS. This method can be used in the field and also in diagnostic and research centres.

Bronchoalveolar lavage fluid cytology and airway hyper-reactivity in clinically normal horses.

OBJECTIVE: To characterise the relationship between bronchoalveolar lavage fluid (BALF) cytology and pulmonary function testing with histamine bronchoprovocation (HBP) methods in a population of clinically normal horses. DESIGN: Cross-sectional study METHODS: Clinically normal adult horses (n = 33) underwent pulmonary function testing and HBP with a commercial flowmetric plethysmography system. BAL was performed 1-5 days later. Statistical analysis was used to assess associations between BALF cell concentration, relative inflammatory cell percentages and categorisation, and airway hyper-reactivity (AHR). RESULTS: AHR (PC35 ≤ 8 mg/mL) was demonstrated in 17 (52%) of the horses. Using current definitions, BALF cytology was consistent with inflammatory airway disease in 14 (42%) of the horses and 7 of those demonstrated either mastocytic and/or eosinophilic responses. There was no correlation between total inflammatory cell counts or relative percentage and AHR. No statistical association was found between BALF inflammatory cell categories and AHR. CONCLUSION: A direct association between cytological evidence of airway inflammation and AHR was not identified in this population of clinically normal horses. Determining the presence and measuring inflammatory cell mediators in BALF may more accurately reflect AHR. In addition, normal values for cell proportions in BALF may vary between different populations of horses and more appropriate regional reference ranges should be established.

Effect of Dexamethasone and Fluticasone on Airway Hyperresponsiveness in Horses With Inflammatory Airway Disease.

BACKGROUND: Airway hyperresponsiveness (AWHR), expressed as hypersensitivity (PC75 RL ) or hyperreactivity (slope of the histamine dose-response curve), is a feature of inflammatory airway disease (IAD) or mild equine asthma in horses. Glucocorticoids are used empirically to treat IAD. OBJECTIVES: To determine whether dexamethasone (DEX) (0.05 mg/kg IM q24h) and inhaled fluticasone (FLUT) (3,000 µg q12h) administered by inhalation are effective in decreasing AWHR, lung inflammation, and clinical signs in horses with IAD. METHODS: A randomized crossover study design was used. Eight horses with IAD were assigned to a treatment group with either DEX or FLUT. Measured outcomes included lung mechanics during bronchoprovocative challenges, bronchoalveolar lavage fluid (BALF) cytology, and scoring of clinical signs during exercise. RESULTS: Dexamethasone and FLUT abolished the increase in RL by 75% at any histamine bronchoprovocative dose in all horses after the first week of treatment. However, after 2 weeks of FLUT treatment, 1 horse redeveloped hypersensitivity. There was a significant decrease in the number of lymphocytes after treatment with both DEX and FLUT (P = .039 for both) but no significant differences in other BALF cell types or total cell counts (P > .05). There was no difference in the scoring of the clinical signs during each treatment and washout period (P > .05). CONCLUSIONS AND CLINICAL IMPORTANCE: Both DEX and FLUT treatments significantly inhibit airway hypersensitivity and hyperreactivity in horses with IAD. There are no significant effects on the clinical signs or the number of inflammatory cells (except lymphocytes) in BALF. The treatments have no residual effect 3 weeks after discontinuation.

Effects of sedation and salbutamol administration on hyperpnoea and tidal breathing spirometry in healthy horses.

Sedation is often required to perform pulmonary function testing (PFT) in horses, but drug effects may influence respiratory function. The current study was designed to characterise the effects of sedation and bronchodilator administration on absolute and relative indices of pulmonary function during eupnoeic respiration and carbon dioxide-induced hyperpnoea (rebreathing) in healthy horses using a pneumotachographic spirometry system. Sedation with acetylpromazine (ACP), xylazine, or both drugs in combination was associated with significant reductions in respiratory frequency, minute ventilation and peak airflows during eupnoeic respiration. Peak expiratory airflow occurred later in the respiratory cycle than was observed in untreated horses, and expiratory relative flow-time indices were also affected during eupnoeic respiration. Rebreathing attenuated the effects of sedation on indices of pulmonary function, suggesting that future studies should consider the use of induced hyperpnoea as part of the spirometry protocol. Based on the finding that all sedative agents had some effect on eupnoeic respiration, albeit least pronounced with ACP, the latter drug should be considered for sedation of horses undergoing PFT. Salbutamol increased peak inspiratory flow during eupnoeic respiration in healthy horses.

Outcomes and prognostic factors of surgical treatments for brachycephalic obstructive airway syndrome in 3 breeds.

OBJECTIVE: To determine prognostic indicators for the surgical treatment of brachycephalic obstructive airway syndrome (BOAS) and to compare the prognosis of 2 multilevel surgical procedures. STUDY DESIGN: Prospective clinical study. SAMPLE POPULATION: Client-owned pugs, French bulldogs, and bulldogs (n = 50). METHODS: Noninvasive whole-body barometric plethysmography (WBBP) was used to assess respiratory function before, 1 month and 6 months after upper airway corrective surgery. Postoperatively, BOAS indices (ie, ascending severity score generated from WBBP data, 0%-100%) that equaled to or exceeded the cut-off values of BOAS in the diagnostic models were considered to have a "poor prognosis." A multivariate logistic regression was used to assess predictors for prognosis. RESULTS: The median BOAS indices decreased after surgery (from 76% to 63%, P < .0001), although dogs with indices in this range would still be considered clinically affected. Age (odds ratios [OR] = 0.96, 95% confidence interval [CI]: 0.93-0.99, P < .05), body condition (OR = 0.06, 95% CI: 0.01-0.39, P < .01), laryngeal collapse (OR = 6.1, 95% CI: 1-37.22, P < .05), and surgical techniques (OR = 7.94, 95% CI: 1.17-54.01, P < .05) were associated with postoperative prognosis. The multivariate model suggests modified multilevel surgery (MMS) may have a better outcome than traditional multilevel surgery (TMS) (P = .034). The positive predictive value of the logistic model was 84% (95% CI: 68-94%) and the area under the receiver operating characteristic (ROC) curve was 89% (95% CI: 78-99%, P <.0001). CONCLUSIONS: Younger age, normal body condition, presence of laryngeal collapse, and treatment with TMS were negative prognostic factors after surgical treatment of BOAS. MMS is recommended, particularly in dogs with a higher probability of poor prognosis.

Reliability of breath by breath spirometry and relative flow-time indices for pulmonary function testing in horses.

BACKGROUND: Respiratory problems are common in horses, and are often diagnosed as a cause of poor athletic performance. Reliable, accurate and sensitive spirometric tests of airway function in resting horses would assist with the diagnosis of limitations to breathing and facilitate investigations of the effects of various treatments on breathing capacity. The evaluation of respiratory function in horses is challenging and suitable procedures are not widely available to equine practitioners. The determination of relative flow or flow-time measures is used in paediatric patients where compliance may limit conventional pulmonary function techniques. The aim of the current study was to characterise absolute and relative indices of respiratory function in healthy horses during eupnoea (tidal breathing) and carbon dioxide (CO2)-induced hyperpnoea (rebreathing) using a modified mask pneumotrachographic technique well suited to equine practice, and to evaluate the reliability of this technique over three consecutive days. Coefficients of variation, intra-class correlations, mean differences and 95% confidence intervals across all days of testing were established for each parameter. RESULTS: The technique provided absolute measures of respiratory function (respiratory rate, tidal volume, peak inspiratory and expiratory flows, time to peak flow) consistent with previous studies and there was no significant effect of day on any measure of respiratory function. Variability of measurements was decreased during hyperpnea caused by rebreathing CO2, but a number of relative flow-time variables demonstrated good agreement during eupnoeic respiration. CONCLUSIONS: The technique was well tolerated by horses and study findings suggest the technique is suitable for evaluation of respiratory function in horses. The use of relative flow-time variables provided reproducible (consistent) results, suggesting the technique may be of use for repeated measures studies in horses during tidal breathing or rebreathing.

Effect of Parachlamydia acanthamoebae on pulmonary function parameters in a bovine respiratory model.

The aim of this study was to evaluate pulmonary dysfunction induced by experimental infection with Parachlamydia acanthamoebae in calves. Intrabronchial inoculation with P. acanthamoebae was performed in 31 calves aged 2-3 months old at two different challenge doses of 10(8) and 10(10) inclusion-forming units (IFU) per animal. Control animals received heat inactivated bacteria. The effects on pulmonary gas exchange were determined by arterial blood gas analysis and haemoximetry during the 7 days post inoculation (DPI). For pulmonary function testing (PFT), impulse oscillometry, capnography, and measurement of O2 uptake were undertaken in spontaneously breathing animals 7 and 3 days before inoculation and were repeated until 10 DPI. In the early phase after challenge (1-3 DPI), mild hypoxaemia occurred, which was accompanied by a significant reduction in both tidal and alveolar volumes (each related to bodyweight, BW). In parallel, expiratory flow rate and specific ventilation (i.e. minute ventilation related to O2 uptake) were significantly increased. Minute and alveolar ventilations (each related to metabolic BW) increased significantly due to higher respiratory rates, lasting until 4 and 5 DPI, respectively. Oxygen uptake was slightly reduced during the first 2 days after challenge, but increased significantly during the recovery phase, from 4 to 8 DPI. No deterioration in respiratory mechanics or acid-base balance was observed. Respiratory infection with 10(10) IFU P. acanthamoebae per calf induced mild respiratory dysfunction, mainly characterised by hypoxaemia. The study's findings do not indicate severe pathophysiological consequences of P. acanthamoebae infection on pulmonary function in the bovine host.

Whole-Body Barometric Plethysmography Characterizes Upper Airway Obstruction in 3 Brachycephalic Breeds of Dogs.

BACKGROUND: A novel test using whole-body barometric plethysmography (WBBP) was developed recently to diagnose brachycephalic obstructive airway syndrome (BOAS) in unsedated French bulldogs. HYPOTHESIS/OBJECTIVES: The hypotheses of this study were: (1) respiratory characteristics are different between healthy nonbrachycephalic dogs and brachycephalic dogs; and among pugs, French bulldogs, and bulldogs; and (2) obesity and stenotic nares are risk factors for BOAS. The main objective was to establish a diagnostic test for BOAS in these 3 breeds. ANIMALS: A total of 266 brachycephalic dogs (100 pugs, 100 French bulldogs, and 66 bulldogs) and 28 nonbrachycephalic dogs. METHODS: Prospective study. Exercise tolerance tests with respiratory functional grading, and WBBP were performed on all dogs. Data from WBBP were associated with functional grades to train quadratic discriminant analysis tools to assign dogs to BOAS+ and BOAS- groups. A BOAS index (0-100%) was calculated for each dog. Receiver operating characteristic (ROC) curves were used to evaluate classification ability. RESULTS: Minute volume was decreased significantly in asymptomatic pugs (P = .009), French bulldogs (P = .026), and bulldogs (P < .0001) when compared to nonbrachycephalic controls. Respiratory characteristics were different among breeds and affected dogs had a significant increase in trace variation. The BOAS index predicted BOAS status for each breed with 94-97% (95% confidence interval [CI], 88.9-100%) accuracy (area under the ROC curve). Both obesity (P = .04) and stenotic nares (P = .004) were significantly associated with BOAS. CONCLUSIONS AND CLINICAL IMPORTANCE: The WBBP can be used as a clinical tool to diagnose BOAS noninvasively and objectively.

An Impedance-Based Model for the Assessment of Cardiopulmonary Function in Rabbits.

Improving the quality of physiologic data collected from research animals is most easily accomplished by collecting as much information as possible from a single subject, thereby reducing animal use and error associated with satellite groups. We investigated the feasibility of using a large-animal implantable telemetry device in New Zealand white rabbits (n = 6). The first task was to develop an implantation technique that yielded calibrated tidal volume (Vt) measurements that were within 10% of those obtained simultaneously from a pneumotachograph, a low-noise electrocardiogram, and stable blood pressure. The second task was to challenge implanted rabbits with the respiratory stimulant doxapram to assess linearity of the calibration across a range of Vt. Of the 3 electrode placements attempted, only one resulted in calibrations consistently below 10% error. Optimal electrode placement resulted in calibrated Vt measurements within 1.7% ± 0.3% of those obtained from a pneumotachograph during normal tidal breathing, 7.3% ± 0.7% of those after saline injection, and 6.0% ± 0.5% of those after doxapram injection. The Vt range was 9 to 15 mL for normal tidal breathing and saline injection and 25 to 30 mL after doxapram injection. Increases in mean arterial pressure of 25.0 ± 6.82 mm Hg and decreases in heart rate of 56.3 ± 6.82 bpm were associated with doxapram injection only. Our findings represent the first time that multiple cardiopulmonary endpoints have been assessed by telemetry in conscious, restrained rabbits. Whether animal position affects calibration accuracy warrants investigation.

Technical note: A facility for respiration measurements in cattle.

A respiration system consisting of 4 climate-controlled chambers and 1 set of flowmeters and analyzers was constructed and validated. Each chamber had volume of 21.10m(3) (3.68×2.56×2.24m) and was made from steel with double-glazed windows on either side enabling visual contact between animals. The chambers are independently climate-controlled and can maintain temperature and relative humidity in a range from 5 to 45°C and 30 to 80%, respectively. A flow generator and mass flowmeter continuously pull air from each chamber and a slight negative pressure inside the chamber is ensured. Air from all chambers and ambient air share a common gas analysis and data acquisition system for monitoring O2, CO2, and CH4 concentrations over the measurement period, with the cycle time set to 20min. Analyzers are regularly calibrated and the chambers have mean recoveries of 99.0 and 98.0% for CO2 and CH4, respectively. The chambers are equipped with infrared cameras and electronic feed and water bins for intake measurements, as well as sensors for monitoring animal position and heart rate. Data acquisition and analysis software is used to calculate the rate of consumption of O2 and production of CO2 and CH4. The dynamic respiration measurements are integrated with feed intake data and other sensors. The daily gas exchanges are estimated by integration to determine methane emission and heat production. We conducted a trial with 12 lactating 3/4 Holstein × 1/4 Gyr crossbred dairy cows (6 multiparous and 6 primiparous) under 2 feeding regimens (ad libitum or restricted) to validate the system. Two 22-h respiration measurements were obtained from each cow. Restricted-fed cows showed lower values for milk yield, methane emission, and heat production compared with ad libitum-fed animals. We found no difference between groups for CH4 produced per kilogram of dry matter intake. Repeatability for CH4 emission and heat production was high (0.97 and 0.92, respectively). The respiration system described herein is a useful tool for measuring the dynamic and accumulated data of heat production, methane emission, and feed intake.

On-Farm Use of Ultrasonography for Bovine Respiratory Disease.

Thoracic ultrasonography (TUS) in young cattle has recently gained momentum as an accurate and practical tool for identifying the lung lesions associated with bovine respiratory disease. As cattle producers increasingly seek input from their veterinarians on respiratory health issues, bovine practitioners should consider adding TUS to their practice models. This article discusses the relevant literature regarding TUS in young cattle, current acceptable techniques, and practical on-farm applications.

Asthma in an Adult Female Vervet Monkey (Chlorocebus sabaeus).

A 9-y-old, colony-bred, female vervet monkey (Chlorocebus sabaeus) presented with a 6-y history of open-mouth breathing, tachypnea, and sibilant wheezing. These symptoms did not significantly affect her activity or quality of life. Thoracic radiographs and results of bronchoalveolar lavage supported the diagnosis of asthma. Treatment comprising intramuscular prednisolone (tapered over 2 mo from twice daily to every other day), inhaled salmeterol-fluticasone (25 µg-250 µg per actuation twice daily) by mask, and a metered dose inhaler was successful in restoring a normal respiratory pattern. Despite the availability of several primate models of human asthma, this case represents the first report of spontaneous asthma in a NHP.