Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
Topic:Pulmonary Health
Pulmonary health in horses encompasses the study of the respiratory system's function, structure, and disorders within equine species. This area of research addresses various conditions affecting the lungs and airways, such as equine asthma, exercise-induced pulmonary hemorrhage (EIPH), and infectious respiratory diseases. The respiratory system's efficiency is vital for horses, particularly those involved in athletic activities, as it influences performance and overall well-being. Research in pulmonary health investigates diagnostic methods, treatment options, and preventive measures for maintaining respiratory function in horses. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, and pathophysiology of the equine respiratory system, as well as the management and therapeutic approaches for respiratory conditions in horses.
Respiratory mucociliary clearance in the horse in health and disease, and its pharmaceutical modification. The structure and possible functions of respiratory secretions are reviewed. In the equine, goblet (mucus producing) cells are the main source but little information is available on the volume or composition of equine respiratory secretions. Airway mucus has complex and incompletely understood physical characteristics which can be partially assessed by a wide range of in vitro and biological techniques. The complex relationship between mucus structure and its propulsion by the airway cilia are discussed, both in health and with pulmonary disease. Mucokinesis in the horse has been assessed visu...
Effect of head and neck position on respiratory mechanics in horses sedated with xylazine. We studied the temporal changes in respiratory mechanics associated with xylazine administration (1.1 mg/kg of body weight, IV) in standing horses (experiment 1), and determined the effects of head and neck position (experiment 2) and atropine administration (experiment 3) on the observed changes. Thoroughbred geldings, 3 to 5 years old (5 in experiment 1, 4 in experiments 2 and 3) were used. Flow rates were obtained from a pneumotachograph and a differential transducer attached to a tight-fitting mask. Electronic integration of the flow signal gave tidal volume. Total pulmonary pressure (PL) ...
Influence of cyclooxygenase inhibitors on furosemide-induced hemodynamic effects during exercise in horses. Furosemide, which commonly is used as a prophylactic treatment for exercise-induced pulmonary hemorrhage in horses, may mediate hemodynamic changes during exercise by altering prostaglandin metabolism. To determine if furosemide's hemodynamic effects during exercise in horses could be reversed, cyclooxygenase inhibitors were administered with furosemide. Four treatments were administered 4 hours prior to treadmill exercise at 9 and 13 m/s. They included a control treatment (10 ml of 0.9% NaCl solution, IV), furosemide (1 mg/kg of body weight, IV) administered alone, and furosemide in combinati...
Respiratory mechanics of horses during stepwise treadmill exercise tests, and the effect of clenbuterol pretreatment on them. Normal Standardbred horses were given an incremental exercise test on a horizontal treadmill to evaluate the influence of exercise on gas exchange, resistance, dynamic compliance and inertance of the respiratory system. The exercise test consisted of 2 min exercise steps at each of the following speeds: 2.4 m/sec (walk), 4.5 m/sec (slow trot), 7.0 m/sec (fast trot) and 10 m/sec (gallop). At rest and after 1 min of exercise at each step, airflow, tidal volume, respiratory frequency, pharyngeal, mid-oesophageal and transdiaphragmatic pressures and arterial blood gas tensions were measured. The s...
Preliminary observations on inhalation and intradermal challenges of horses with oil seed rape. Horses with asymptomatic or symptomatic chronic obstructive pulmonary disease (COPD) and control horses were challenged with oil seed rape either by exposure to a field of flowering Brassica campestris for six days, or by an inhalation challenge with freshly collected pollen from Brassica napus, or by inhalation challenge with a commercial extract of B napus pollen. Clinical and bronchoscopic examinations showed that the challenges did not induce detectable pulmonary disease in the control or asymptomatic COPD affected horses and did not significantly affect their pulmonary mechanics, arterial...
Effects of transport on constituents of bronchoalveolar lavage fluid from horses. To determine whether road transport affected pulmonary phagocyte activity, 7 healthy Thoroughbred horses were shipped 1,160 kilometers over 36 hours. Fluid collected by bronchoalveolar lavage (BAL) 12 hours, and 7 and 14 days after transport was analyzed. Results were compared to those from the same horses pre-transport, and 7 non-transported control horses that had BAL performed at the same times as the transported horses. Of cells recovered with BAL the percentage of viable pulmonary alveolar macrophages (PAMs) declined from 90.0 +/- 0.9% pre-transport to 80.0 +/- 3.7% by 2 weeks post transp...
Increased pulmonary production of immunoreactive 15-hydroxyeicosatetraenoic acid in an animal model of asthma. Airway obstruction and hyperreactivity are characteristics of human asthma and of "heaves," a naturally occurring respiratory disorder of horses and ponies. We measured pulmonary function and plasma immunoreactive 15-hydroxyeicosatetraenoic acid (i15-HETE) concentrations in simultaneously collected carotid artery and right ventricle blood samples in five affected ponies and their age- and gender-matched control ponies. Measurements and sampling were performed before (Period A), during (Period B), and following recovery from (Period C) acute airway obstruction precipitated by housing ponies in ...
Influence of furosemide on hemodynamic responses during exercise in horses. Four hours prior to exercise on a high-speed treadmill, 4 dosages of furosemide (0.25, 0.50, 1.0, and 2.0 mg/kg of body weight) and a control treatment (10 ml of 0.9% NaCl) were administered IV to 6 horses. Carotid arterial pressure (CAP), pulmonary arterial pressure (PAP), and heart rate were not different in resting horses before and 4 hours after furosemide administration. Furosemide at dosage of 2 mg/kg reduced resting right atrial pressure (RAP) 4 hours after furosemide injection. During exercise, increases in treadmill speed were associated with increases in RAP, CAP, PAP, and heart rate...
Pulmonary artery and aortic pressure changes during high intensity treadmill exercise in the horse: effect of frusemide and phentolamine. Intravenous frusemide (1.0 mg/kg bwt) or phentolamine (0.33 mg/kg bwt) was given to 7 horses 1 h before exercise and their effects on pulmonary artery and aortic pressure changes during strenuous exercise were examined. Short-term near-maximal treadmill exercise (10 m/sec, 3 degrees incline) produced increases in heart rate, mean pulmonary artery pressure (PAP), mean aortic pressure (AP), and packed cell volume (PCV). Frusemide did not affect heart rate, PAP or PCV during exercise. Frusemide significantly decreased mean AP by 10 to 15 mmHg during exercise. Phentolamine produced an increase in ...
Aerosol pirbuterol: bronchodilator activity and side effects in ponies with recurrent airway obstruction (heaves). The dose of aerosol pirbuterol that could be administered safely to ponies (weight approximately 200 kg) was determined by observation for sweating, trembling and excitement and measurement of heart and respiratory rates during cumulative administration of the drug. Sweating, trembling and excitement were first observed following a dose of 2,400 micrograms and became more severe at 3,200 micrograms. These effects were accompanied by an increase in heart rate but not a change in respiratory rate. When 3200 micrograms was administered without prior administration of lower doses, side effects wer...
Pulmonary blood flow distribution in anesthetized ponies. Results of recent investigations in humans and dogs indicate that gravity-independent factors may be important in determining the distribution of pulmonary blood flow. To further evaluate the role of gravity-independent factors, pulmonary blood flow distribution was examined using 15-microns radionuclide-labeled microspheres in five prone ponies over 5 h of pentobarbital sodium anesthesia. The ponies were killed, and the lungs were excised and dried by air inflation (pressure 45 cmH2O). The dry lungs were cut into transverse slices 1-2 cm thick along the dorsal-ventral axis, parallel to gravit...
Effect of chronic hypoxia on breathing and EMGs of respiratory muscles in awake ponies. Breathing, diaphragmatic and transversus abdominis electromyograms (EMGdi and EMGta, respectively), and arterial blood gases were studied during normoxia (arterial PO2 = 95 Torr) and 48 h of hypoxia (arterial PO2 = 40-50 Torr) in intact (n = 11) and carotid body-denervated (CBD, n = 9) awake ponies. In intact ponies, arterial PCO2 was 7, 5, 9, and 11 Torr below control (P less than 0.01) at 1 and 10 min and 5 and 24-48 h of hypoxia, respectively. In CBD ponies, arterial PCO2 was 3-4 Torr below control (P less than 0.01) at 4, 5, 6, and 24 h of hypoxia. In intact ponies, pulmonary ventilation, ...
Modelling exercise-induced pulmonary hemorrhage in racing thoroughbreds. Exercise-induced pulmonary hemorrhage (EIPH) affects a large portion of racing thoroughbred horses. Sites of hemorrhage and causal mechanisms remain unestablished. Our mathematical model was constructed to test the hypothesis that EIPH could be caused by a combination of respiratory and circulatory mechanical factors occurring during exercise. Various physiological data for respiration, blood circulation and exercise were incorporated into the model. Results show that inhalation pressure drops across airway resistances become great enough during exercise to cause rupture of capillaries for bot...
Bronchoalveolar lavage findings in horses with exercise intolerance. Significant differences were detected by bronchoalveolar lavage (BAL) between horses racing successfully and those showing exercise intolerance. Neutrophil percentage, haemosiderophage percentage and total bacterial numbers were significantly elevated in horses with exercise intolerance. BAL provided a more accurate indication of the incidence and extent of exercise induced pulmonary haemorrhage (EIPH) than visual inspection.
Use of scintigraphy for the determination of mucociliary clearance rates in normal, sedated, diseased and exercised horses. Mucociliary clearance rates from the trachea were determined in normal, sedated, diseased and exercised horses from scintigraphs obtained after an injection of technetium-99m sulphide colloid into the tracheal lumen. The group mean tracheal clearance rate of eight clinically normal horses during 42 trials was 2.06 +/- 0.38 cm/min. Significant between horse differences were found (p less than 0.05). When six and seven of these horses were given xylazine and detomidine hydrochloride, respectively, mean group tracheal clearance rates dropped significantly (p less than 0.05). The decreases from ea...
Pulmonary aspergillosis associated with acute enteritis in a horse. Invasive pulmonary aspergillosis was detected at postmortem examination of an 8-year-old Quarter Horse mare that had a history of diarrhea, laminitis, and bilateral nasal discharge. A diagnosis of Ehrlichia risticii infection was made on the basis of clinical signs of diarrhea and pyrexia, high serum antibody titer to E risticii (1:2,560), and multiple Salmonella-negative cultures obtained from fecal and colonic specimens. Possible pathogenic mechanisms contributing to the development of pulmonary aspergillosis secondary to enteric disease include mycotic invasion of the intestinal tract or im...
Neutrophil migration induced by equine respiratory secretions, bronchoalveolar lavage fluids and culture supernatants of pulmonary lavage cells. Supernatants of equine respiratory secretions enhanced the migration of equine neutrophils into the lower compartments of Boyden chambers. Checkerboard analysis revealed that the neutrophil migration promoting activity (NMPA) of secretion specimens was in great part caused by chemokinesis, irrespective of the neutrophil score of the specimen. The NMPA of respiratory secretions was correlated neither with the neutrophil score of the secretion specimen nor with the severity of the chronic pulmonary disease. Respiratory secretions collected while horses were kept under low dust or under dusty hou...
Beta-adrenergic receptor activity in ponies with recurrent obstructive pulmonary disease. Pulmonary function measurements were made in control ponies and in ponies with recurrent obstructive pulmonary disease (principals) during clinical remission and during an attack of acute airway obstruction. The ponies were given beta-adrenergic antagonists and agonists to determine the role of beta receptors in recurrent obstructive pulmonary disease, and to determine the subtypes of beta receptors mediating bronchodilation in ponies. Aerosol administration of the beta antagonists, propranolol (beta 1 and beta 2), atenolol (beta 1), and butoxamine (beta 2) decreased dynamic compliance (Cdyn) ...
Unilateral hypoxic pulmonary vasoconstriction in the dog, pony and miniature swine. The hypoxic pulmonary vasoconstrictor response to unilateral hypoxia was analyzed in pentobarbital anesthetized dogs (n = 5), miniature swine (n = 5), and ponies (n = 5). The left and right lungs (LL, RL) were separately ventilated with the LL exposed to inspired oxygen concentrations (CIO2) of 100%, 12%, 8% or 4%, while the RL always received a CIO2 = 100%. Pulmonary blood flow distribution was measured using 15 microns radioactive microspheres. LL PAO2, and percent pulmonary blood flow diversion (%FD) were calculated at each CIO2. At CIO2 of 4% there were significant differences (P greater t...
Nuclear imaging techniques for equine respiratory disease. When performed on selected clinical cases, ventilation/perfusion scintigraphy provides valuable additional information on regional lung function that is not obtainable from conventional thoracic radiographs. This is particularly true of horses with EIPH, COPD, and those suspected of having some form of small-airway disease. For horses with EIPH, the presence of a perfusion deficit on the scan is considered a key prognostic sign, because it is likely in these cases that irreversible bronchial arterial takeover has occurred in the affected areas of lung. Findings from horses with COPD have impro...
Application of clinical exercise testing for identification of respiratory fitness and disease in the equine athlete. Maximal exercise testing is a valuable diagnostic tool for the evaluation of exercise intolerance and level of fitness in the equine athlete. A description of the standardized incremental exercise testing protocol and interpretation of the results of the test is followed by a discussion of more specific diagnostic techniques aimed at identifying pulmonary dysfunction as a cause of suboptimal performance.
Pulmonary gas exchange correlated to clinical signs and lung pathology in horses with chronic bronchiolitis. Eight horses (mean weight 438 kg) with chronic obstructive pulmonary disease (COPD) were studied for clinical signs, ventilation/perfusion relationships (VA/Q) and lung morphology. Four horses were killed and necropsied after the study. In horses with COPD, minute ventilation was almost twice as high as normal, whereas PaO2 was significantly decreased. Cardiac output was normal, but pulmonary artery pressure and pulmonary vascular resistance were significantly increased. The VA/Q distribution was abnormal with an increased scatter of VA/Q ratios. However, shunt (VA/Q = 0) was increased in one ...
Pharmacology of furosemide in the horse: a review. Furosemide, a diuretic, is frequently administered to horses for the prophylaxis of exercise-induced pulmonary hemorrhage and the treatment of a number of clinical conditions, including acute renal failure and congestive heart failure. Furosemide increases the rate of urinary sodium, chloride, and hydrogen ion excretion. Plasma potassium concentration decreases after furosemide administration but urinary potassium excretion in horses is minimally affected. Renal blood flow increases after furosemide administration. Systemically, furosemide increases venous compliance and decreases right atrial...
Mechanical properties of the isolated equine trachea. In order to study the in vitro mechanical properties of the equine trachea submitted to the compressive pressures observed in vivo, the pressure-volume relationship was determined in intra- and extra-thoracic tracheal segments taken post mortem from 29 healthy horses (one to 15 years old; 352 to 651 kg). At the same time, the cross-sectional lumen area (X-SA) at the mid-point of the segment was measured using a slit-lamp transillumination and photographic measurement by endoscopy. The tracheal specific compliance (Cs) as well as the relative changes in X-SA and in the sagittal and transverse d...
Histamine inhalation challenge in normal horses and in horses with small airway disease. A histamine inhalation challenge (HIC) procedure was developed to assess hyperreactive states in horses. Following clinical evaluation, percutaneous lung biopsies were performed on nine light breed mares aged 6 to 15 years. Five horses, with normal small airways, were classified as group A and four subjects with small airway disease (SAD) lesions formed group B. Pulmonary mechanics parameters were monitored following an aerosol of 0.9% saline and every 5 min for up to 30 min after HIC with 0.5% w/v of histamine diphosphate, administered through a face mask for 2.5 min. Tidal volume (VT) and ai...
Ventilatory compensation for lactacidosis in ponies: role of carotid chemoreceptors and lung afferents. We investigated changes in arterial PCO2 (PaCO2) and pulmonary ventilation (VE) in normal, carotid chemoreceptor-denervated, and hilar nerve-denervated ponies during intravenous lactic acid infusion at rest and treadmill exercise at 1.8 mph-5% grade (mild) and 1.8 mph-15% grade (moderate). Lactic acid, (0.5 M) infusion of 0.10, 0.13, and 0.20 ml.min-1.kg-1 at rest and mild and moderate exercise increased arterial [H+] linearly throughout the 10 min of acid infusion. At 10 min of infusion, arterial [H+] had increased approximately 20 nmol/l (0.2 pH units) for each condition and group. Under mos...
