Lower airway function: response to exercise and training

peer reviewe

Parathyroid hormone evaluation in normal horses and horses with renal failure

Immunoreactive parathyroid hormone (iPTH), calcium, and inorganic phosphorus levels were measured in the serum of 13 apparently normal horses and in six horses with renal insufficiency. Serum iPTH levels were measured by radioimmunoassay using an antisera produced by immunization of guinea pigs with bovine parathyroid hormone. The antisera reacts primarily with the carboxy-terminal hormone fragment. Serum iPTH level in the normal horses was 504.5 ± 191.4 pg/ml and varied from 246 to 750 pg/ml. Serum iPTH levels in three horses with chronic renal failure, hypercalcemia and hypophosphatemia were below the limits of detection for the assay (<165 pg/ml). The hypercalcemia and hypophosphatemia were thus considered not to be the result of increased parathyroid hormone. Three horses with renal insufficiency which were not hypercalcemic had serum iPTH levels which were normal or greater than normal

Workload of horses on a water treadmill: effect of speed and water height on oxygen consumption and cardiorespiratory parameters

Abstract Background Despite the use of water treadmills (WT) in conditioning horses, the intensity of WT exercise has not been well documented. The workload on a WT is a function of water height and treadmill speed. Therefore, the purpose of this study was to determine the effects of these factors on workload during WT exercise. Fifteen client-owned Quarter Horses were used in a randomized, controlled study. Three belt speeds and three water heights (mid cannon, carpus and stifle), along with the control condition (dry treadmill, all three speeds), were tested. Measured outcomes were oxygen consumption (V̇O2), ventilation (respiratory frequency, tidal volume (VT)), heart rate (HR), and blood lactate. An ergospirometry system was used to measure V̇O2 and ventilation. Linear mixed effects models were used to examine the effects of presence or absence of water, water height and speed (as fixed effects) on measured outcomes. Results Water height and its interaction with speed had a significant effect on V̇O2, VT and HR, all peaking at the highest water level and speed (stifle at 1.39 m/s, median V̇O2 = 16.70 ml/(kg.min), VT = 6 L, HR = 69 bpm). Respiratory frequency peaked with water at the carpus at 1.39 m/s (median 49 breaths/min). For a given water height, the small increments in speed did not affect the measured outcomes. Post-exercise blood lactate concentration did not change. Conclusions Varying water height and speed affects the workload associated with WT exercise. The conditions utilized in this study were associated with low intensity exercise. Water height had a greater impact on exercise intensity than speed

Effects of inhaled dry powderipratropium broide on reconvery from exercise of horses with COPD

The present study evaluated ventilatory, cardiovascular and metabolic parameters during recovery from strenuous exercise in horses suffering from a crisis of chronic obstructive pulmonary disease (COPD) and to determine whether ipratropium dry powder inhalation (DPI) before exercise has an effect on these parameters. When 6 saddle horses, affected with COPD, developed airway obstruction, they inhaled placebo and ipratropium (2400 pghorse), the order being randomly chosen. Pulmonary function tests were then recorded 15 min after inhalation. Following these tests, the horses underwent a strenuous treadmill exercise, followed by a ecovery period that consisted of a 10 min walk. Measurements were made at the first and tenth min of recovery. Respiratory flow, 0 2 and C02 fractions in the respired gas, pleural pressure changes and heart rate were recorded. Arterial and mixed venous blood samples were analysed or gas tensions, haemoglobin and plasma lactate concentrations. Oxygen consumption (Wz), C02 production, tidal volume, alveolar oxygen tension (PAOz), alveolar ventilation, the alveolar-pulmonary capillary oxygen difference ((A-a)dOz) and total pulmonary resistance (RL) were measured. The PA02 was the only parameter significantly improved during recovery following ipratropium DPI. This improvement was not accompanied by evidence of improvement of other ventilatory or cardiorespiratory parameters. The results showed that in horses suffering from a crisis of COPD, recovery is characterised by an exercise-induced bronchodilation. Secondly, ipratropium DPI at a dose of 2400 pghorse is an effective bronchoddator in these horses at rest but it has little effect on the airway calibre during the recovery period. It is suggested that the short term recovery period is still Muenced by exercise-induced adjustments that may exceed the bronchodilatory effect of inhaled ipratropium that are observed before exercis

Prevalence and severity of exercise‐induced pulmonary hemorrhage in 2‐year‐old Thoroughbred racehorses and its relationship to performance

Abstract Background Little has been reported regarding the prevalence and severity of exercise‐induced pulmonary hemorrhage (EIPH) in 2‐year‐old Thoroughbred racehorses. Objectives Evaluate EIPH prevalence and severity and its association with performance, speed index, furosemide administration, race distance, and track surface. Animals A total of 830 2‐year‐old Thoroughbreds. Methods Prospective blinded observational study. Videoendoscopy was performed 30 to 60 minutes postrace at 15 American racetracks. Three blinded observers independently assigned an EIPH grade (0‐4) to each video, and prevalence and severity of EIPH were determined. Relationships of EIPH grade to performance, speed index, race distance, track surface, and prerace administration of furosemide were evaluated using Pearson's chi‐squared test for categorical variables and analysis of variance (ANOVA) for numerical variables. Multivariable logistic regression assessed relationships between EIPH prevalence and severity, respectively, and the aforementioned independent variables. A P < .05 was considered significant. Results A total of 1071 tracheoendoscopies were recorded. The EIPH prevalence was 74% and for EIPH grade ≥3 was 8%. Speed index (P = .02) and finishing place (P = .004) were lower with EIPH ≥3. The EIPH prevalence and severity were lower at 2 tracks where postrace tracheoendoscopy was mandatory rather than voluntary (P < .001). Probability of observing EIPH was negatively associated with speed index (P = .01) at tracks where postrace tracheoendoscopy was mandatory. Prerace furosemide administration decreased the probability of EIPH occurrence (P = .007) and severity (P = .01) where study participation was voluntary. Conclusions and Clinical Importance Prevalence and severity of EIPH in 2‐year‐old racehorses were consistent with that of older racehorses. An EIPH grade ≥3 was associated with decreased performance. Prerace furosemide administration was associated with a decreased likelihood, but not severity, of EIPH at most tracks