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.
de Wasseige S, Picotte K, Lavoie JP.A study reported low systemic availability of injectable dexamethasone nebulized to healthy horses using the Flexineb mask. When used in horses with severe asthma and a different nebulizer, lack of efficacy and cortisol suppression were observed. Objective: Nebulized dexamethasone is as effective as PO administration for the treatment of severe asthma in horses. Methods: Twelve horses with severe asthma from a research herd. Methods: Randomized clinical trial. Horses were divided into 2 groups and received 5 mg of dexamethasone sodium phosphate by nebulization using a Flexineb mask (NE, n = 6)...
Leventhal HR, McKenzie HC, Estell K, Council-Troche M, Davis JL.The objective of this study was to determine the pharmacokinetics and tolerability of tulathromycin (Draxxin ; 2.5 mg/kg once) after intramuscular (IM), subcutaneous (SC), and slow intravenous (IV) administration to six adult horses. A three-phase design and 4-week washout period were used. Drug concentrations in blood and bronchoalveolar lavage (BAL) samples were determined by ultra-performance liquid chromatography tandem mass spectrometry and pharmacokinetic parameters calculated using noncompartmental analysis. Following SC and IM administration, all horses exhibited sweating, discomfort,...
Dixon CE, Bedenice D, Mazan MR.Airway hyperresponsiveness (AHR) is linked to airway inflammation and is considered a key manifestation of mild/moderate equine asthma (EA). The study purpose was to determine whether two modalities of non-invasive lung function testing (FOM-forced oscillatory mechanics vs. FP-flowmetric plethysmography) establish the same clinical diagnosis of AHR in horses, using histamine bronchoprovocation. Nineteen horses (3-25 years, 335-650 kg) with clinical signs suggestive of mild/moderate equine asthma were enrolled. FOM and FP testing was performed in each horse on two consecutive days, using a rand...
Daly AE, Deible CG, Lamb CE, Santacaterina SM, Marzolf NL, Page AE, Horohov DW, Wood PL, Werre SR, Chapman SE, Christmann U.To evaluate surfactant protein D (SP-D) concentrations in serum and bronchoalveolar lavage fluid (BALF) from young healthy horses on pasture or housed in a typical barn. Methods: 20 young healthy horses. Methods: Horses were randomly assigned to 1 of 2 groups (pasture, n = 10; barn, 10), and serum and BALF samples were collected for SP-D determination at baseline (all horses on pasture) and 2 weeks and 4 weeks after the barn group of horses was relocated from the pasture to the barn. Other evaluations included physical and tracheoscopic examinations. Findings were compared within and between g...
Cerullo M, Driessen B, Douglas H, Hopster K. In anesthetized adult horses, changes in recumbency can influence the cardiovascular system but how arterial blood pressures and oxygen tension change in isoflurane anesthetized animals as a direct result of hoisting has not been investigated. To evaluate effects of hoisting on hemodynamic function and pulmonary gas exchange in isoflurane-anesthetized horses. Prospective, experimental study. Six adult horses were anesthetized three times using isoflurane in pure oxygen (inspired fraction 0.9-1.0), and allowed breathing spontaneously in lateral recumbency. After 45 min horses were hoisted u...
Anderson SL, Duke-Novakovski T, Robinson AR, Townsend HGG, Singh B.The objective of this study was to determine the effect of pulmonary intravascular macrophage depletion on systemic inflammation and ex vivo neutrophil apoptosis using an experimental model of intestinal ischemia and reperfusion injury in horses. Neutrophils were isolated before and after surgery from horses that were randomized to three treatment groups, namely, sham celiotomy (CEL, = 4), intestinal ischemia and reperfusion (IR, = 6), and intestinal ischemia and reperfusion with gadolinium chloride treatment to deplete pulmonary intravascular macrophages (PIMs, IRGC, = 6). Neutrophil apopt...
Adler DMT, Hopster K, Hopster-Iversen C, Fenner M, Buhl R, Jacobsen S.Thoracotomy is an uncommon procedure in horses but remains essential in a variety of cases of pleuropneumonia, pericarditis, thoracic trauma or diaphragmatic herniation, and for experimental thoracic and cardiac procedures. This study aimed at developing an experimental surgical procedure allowing access to the entire circumference of the heart and describing the effect of thoracotomy on pulmonary gas exchange in these horses. The study consisted of two arms, arm one (undergoing thoracotomy), was a terminal experimental study that included 11 Standardbred horses with experimentally induced (by...
Ceriotti S, Bullone M, Leclere M, Ferrucci F, Lavoie JP.Pulmonary hypertension and cor pulmonale are complications of severe equine asthma, as a consequence of pulmonary hypoxic vasoconstriction. However, as pulmonary hypertension is only partially reversible by oxygen administration, other etiological factors are likely involved. In human chronic obstructive pulmonary disease, pulmonary artery remodeling contributes to the development of pulmonary hypertension. In rodent models, pulmonary vascular remodeling is present as a consequence of allergic airway inflammation. The present study investigated the presence of remodeling of the pulmonary arter...
Warlick LM, Léguillette R, Kogan C, Gold JR, Bayly WM.Diagnosis and assessment of severity of exercise-induced pulmonary hemorrhage (EIPH) relies on postexercise visualization of fresh blood in the airways via tracheobronchoscopic examination (TBE) and/or counting erythrocytes in bronchoalveolar lavage fluid (BALFRBC). Determining the BALFRBC is more sensitive than TBE but its usefulness is hampered by the need to have BALFRBC counted at a laboratory. We explored the feasibility of evaluating the severity of EIPH by using a color chart comprised of five shades of red and matching those colors with the color of BALF immediately following collectio...
Marzahl C, Aubreville M, Bertram CA, Stayt J, Jasensky AK, Bartenschlager F, Fragoso-Garcia M, Barton AK, Elsemann S, Jabari S, Krauth J, Madhu P....Exercise-induced pulmonary hemorrhage (EIPH) is a common condition in sport horses with negative impact on performance. Cytology of bronchoalveolar lavage fluid by use of a scoring system is considered the most sensitive diagnostic method. Macrophages are classified depending on the degree of cytoplasmic hemosiderin content. The current gold standard is manual grading, which is however monotonous and time-consuming. We evaluated state-of-the-art deep learning-based methods for single cell macrophage classification and compared them against the performance of nine cytology experts and evaluated...
Carrillo MF, Kemper D, Woods LW, Carvallo FR.A 22-y-old American Quarter Horse gelding was presented with a history of chronic progressive respiratory problems and a diffuse pulmonary nodular pattern in thoracic radiographs. The horse was euthanized, and 4 formalin-fixed samples of lung were submitted for histopathology. There were multifocal areas of marked thickening of alveolar septa as a result of proliferation of myofibroblasts embedded in fibromyxoid matrix (interpreted as "Masson bodies"), focal areas of fibrosis, and numerous papillary projections of connective tissue into bronchioles. A diagnosis of organizing pneumonia was reac...
Millares-Ramirez EM, Picotte K, Lavoie JP.Intra-articular (IA) administration of corticosteroids is performed routinely in equine practice. The lung function of severe asthmatic horses has recently been shown to be improved by IA triamcinolone acetonide (TA). We therefore hypothesised that IA methylprednisolone acetate (MPA), another commonly used corticosteroids, would also decrease the airway obstruction in severe asthmatic horses. Objective: To compare the effects of intra-articular (IA) and intramuscular (IM) methylprednisolone acetate (MPA) administration on lung function and serum cortisol levels in horses with severe asthma. Me...
Pye J, Kilcoyne I, Roy M, Vaughan B, Ormond C, Spriet M.A 20-year-old Quarter horse gelding was referred for evaluation of an acute onset non-weight-bearing right forelimb lameness. Marked soft tissue swelling was apparent over the right scapula and shoulder region; no crepitus was palpable. A complete transverse fracture of the scapular neck was suspected based on ultrasonography and radiographs were obtained to confirm the presumptive diagnosis. A complete, oblique fracture of the right scapular neck with mild cranial and proximal displacement of the distal fragment was detected. Computed tomography of the upper right forelimb was performed post-...
Lopez Sanchez CM, Kogan C, Gold JR, Sellon DC, Bayly WM.Exercise-induced pulmonary hemorrhage (EIPH) is diagnosed and its severity assessed by post-exercise tracheobronchoscopy, and enumeration of bronchoalveolar lavage fluid red blood cells (BALFRBC). Minimal information is available regarding the relationship of tracheobronchoscopy score to BALFRBC number. Objective: Evaluate the relationship between BALFRBC number and tracheobronchoscopy scores and determine their diagnostic sensitivities. Methods: Nine sedentary horses, 21 fit Thoroughbreds, 129 Barrel Racers. Methods: Normal BALFRBC number and the effect of bronchoalveolar lavage (BAL) on it w...
Siwinska N, Zak A, Slowikowska M, Krupinska P, Niedzwiedz A.Asthma is one of the most common non-infectious respiratory diseases in horses. Ultrasound examination is a widely available non-invasive additional diagnostic tool. To date, there are no studies focusing on ultrasonographic findings in horses with asthma. The aim of this study was to analyse the prevalence and severity of ultrasound lesions in lung tissue in horses with asthma. Lung ultrasonography was carried out on six healthy horses (controls) and 12 horses with asthma (six with mild and six with severe asthma). The sonographic changes in three lung sections were assessed using a scoring s...
Hensel M, Meason-Smith C, Plumlee QD, Myers AN, Coleman MC, Lawhon S, Rodrigues Hoffmann A, Rech RR.Pulmonary mycosis secondary to enterocolitis is an uncommon diagnosis in equine medicine, but is thought to result from mucosal compromise and translocation of enteric fungi. The aetiological agent associated with translocation is often identified based on fungal culture or hyphal features in histological sections. In order to understand better the aetiological agents involved, six horses diagnosed with Salmonella enteritis and concurrent pulmonary mycosis were identified retrospectively through a database search of veterinary teaching hospital records. Samples from these cases were subjected ...
Bullone M, Lavoie JP.Human asthma is a complex and heterogeneous disorder characterized by chronic inflammation, bronchospasm and airway remodeling. The latter is a major determinant of the structure-function relationship of the respiratory system and likely contributes to the progressive and accelerated decline in lung function observed in patients over time. Corticosteroids are the cornerstone of asthma treatment. While their action on inflammation and lung function is well characterized, their effect on remodeling remains largely unknown. An important hindrance to the study of airway remodeling as a major focu...
Blott S, Cunningham H, Malkowski L, Brown A, Rauch C.Exercise-induced pulmonary haemorrhage (EIPH) occurs in horses performing high-intensity athletic activity. The application of physics principles to derive a 'physical model', which is coherent with existing physiology and cell biology data, shows that critical parameters for capillary rupture are cell-cell adhesion and cell stiffness (cytoskeleton organisation). Specifically, length of fracture in the capillary is a ratio between the energy involved in cell-cell adhesion and the stiffness of cells suggesting that if the adhesion diminishes and/or that the stiffness of cells increases EIPH is ...
Tarancón I, Armengou L, Melendez-Lazo A, Pastor J, Ríos J, Jose-Cunilleras E.To assess the prevalence of exercise-induced pulmonary hemorrhage (EIPH) among elite endurance horses after competition in a long-distance race. 20 endurance horses and 12 nonexercised or minimally exercised age-, breed-, and trainer-matched horses from the same environment (control horses). Bronchoalveolar lavage fluid samples collected from endurance horses at 3 to 8 days (sample A) and 36 to 38 days (sample B) after the race (100 km in 1 day [n = 3], 70 km/d for 2 days [12], or 100 km/d for 2 days [5]) were cytologically examined for the presence of hemosiderophages. Samples from control ho...
Caivano D, Corda A, Rishniw M, Giorgi ME, Parpaglia MLP, Conti MB, Porciello F, Birettoni F.Equine cardiovascular structures and function are routinely assessed by transthoracic echocardiography. Recently, investigators have described the echocardiographic visualization of equine pulmonary vein ostia. In companion animals, the right pulmonary vein (RPV) to right pulmonary artery (RPA) ratio has been used as an index to estimate the severity of cardiac diseases resulting in left ventricular volume overload. We sought to assess the feasibility of measuring RPV and RPA dimensions, and sought to provide various previously examined RPV and RPA variables in clinically healthy horses that c...
Issouf M, Vargas A, Boivin R, Lavoie JP.Airway wall remodeling, including hyperplasia and hypertrophy of smooth muscle (ASM) cells leading to an increased smooth muscle mass, is considered central to asthma. However, molecular pathways responsible for ASM remodeling remain poorly understood. MicroRNAs (miRNAs) have emerged as key regulators of inflammatory and repair processes affecting the lungs and can downregulate protein expression by inhibiting target mRNA translation. We therefore hypothesized that miRNAs are involved in ASM remodeling in asthma by modulating ASM proliferation. We have analyzed the expression of miRNAs in bron...
Secombe CJ, van Eps AW, Bruce M, Lester GD.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. Methods: 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...
Airway obstruction is the main trait of severe equine asthma that affects respiratory function and elicits detrimental effects on clinical presentation. Only few and underpowered clinical studies have investigated the impact of improvement in lung function induced by bronchodilators on the clinical signs of asthma-affected horses. Objective: To identify the minimal important difference (MID) in lung function elicited by bronchodilator leading to a meaningful improvement in clinical signs. Methods: Pairwise meta-analysis and meta-regression analysis. Methods: Literature searches were performed ...
Varner KM, Hopster K, Driessen B.To assess effects of nitrogen and helium on efficacy of an alveolar recruitment maneuver (ARM) for improving pulmonary mechanics and oxygen exchange in anesthetized horses. Methods: 6 healthy adult horses. Methods: Horses were anesthetized twice in a randomized crossover study. Isoflurane-anesthetized horses in dorsal recumbency were ventilated with 30% oxygen and 70% nitrogen (treatment N) or heliox (30% oxygen and 70% helium; treatment H) as carrier gas. After 60 minutes, an ARM was performed. Optimal positive end-expiratory pressure was identified and maintained for 120 minutes. Throughout ...
Ochi A, Sekiguchi M, Tsujimura K, Kinoshita T, Ueno T, Katayama Y.Equine multinodular pulmonary fibrosis (EMPF) is a recently described form of interstitial pneumonia associated with equine herpesvirus type 5 (EHV-5). This disease has been reported in North and South America, Europe and Oceania but not, to our knowledge, in horses in Japan. We diagnosed EMPF in two Thoroughbred horses in Japan on the basis of gross and histopathological findings. In both cases, significant gross lesions, restricted to the lungs, consisted of numerous firm and coalescing nodules widely distributed throughout the lung. The nodules were <3 cm in diameter and pale white to t...
Wiklund M, Kellgren M, Wulcan S, Grubb T, Nyman G.Administration of pulsed inhaled nitric oxide (PiNO) improves arterial oxygenation in spontaneously breathing anaesthetised healthy horses and in horses undergoing colic surgery. However, because hypoventilation commonly occurs, horses are often mechanically ventilated to prevent hypercarbia. Objective: To evaluate the effects of PiNO on arterial oxygenation during anaesthesia in mechanically ventilated healthy horses and horses undergoing colic surgery. Methods: Prospective nonblinded clinical trial. Methods: Fifty horses undergoing elective arthroscopy (Group A) and 30 horses undergoing coli...
Varegg MS, Kløverød KM, Austnes MK, Siwinska N, Słowikowska M, Zak A, Madej JA, Kandefer-Gola M, Ciaputa R, Nowak M, Niedzwiedz A.Pulmonary hemorrhage is a rare cause of death in horses. Hemorrhage within the respiratory tract has many causes, including mycosis of the guttural pouch, invasive procedures causing serious trauma to nasal conchae, or lung biopsy. We report on a rare case of a fatal pulmonary hemorrhage in a horse after a severe cough during bronchoalveolar lavage. To the best of our knowledge, this is the first report of spontaneous hemorrhage in a horse during bronchoalveolar lavage. Methods: A 21-year-old mare which belonged to the didactic herd of The Faculty of Veterinary Medicine underwent BAL procedure...
Crispe EJ, Lester GD.Exercise-induced pulmonary hemorrhage (EIPH) occurs commonly in horses undergoing strenuous exercise. Reported risk factors include racing in cold temperatures and wearing of bar shoes. In horses with documented moderate to severe EIPH, increasing the interval between races and adopting a negative race pace strategy may reduce the severity of EIPH in subsequent races. EIPH seems to have an impact on performance only when moderate to severe. This occurs in a small number of starters, approximately 6%. EIPH often is erratic in severity from race to race, although across a population it is weakly...
Franklin SH, Van Erck-Westergren E, Bayly WM.Horses are elite athletes when compared with other mammalian species. In the latter, performance is limited by cardiovascular or musculoskeletal performance whereas in athletic horses it is the respiratory system that appears to be rate limiting and virtually all horses exercising at high intensities become hypoxaemic and hypercapnoeic. This is due to both diffusion limitation and a level of ventilation inadequate for the metabolic level that enables horses to exercise at these intensities. In conjunction with these blood gas changes, total pulmonary resistance increases and the work of breath...
Lapointe JM, Vrins A, McCarvill E.Sixty Standardbred horses, aged 3 to 10 years, were examined endoscopically for exercise-induced pulmonary haemorrhage (EIPH) 1 h after racing, on at least 3 occasions. Racing time, finishing position and post exercise venous lactate concentrations were also recorded. Horses positive for tracheal blood on endoscopy were classified as having either grade 1 EIPH (one or a few spots of blood in the trachea), or grade 2 (stream of blood). Air temperature, relative humidity and air pollutant levels were recorded on each examination day. Of the 60 horses, 52 (87%) were EIPH-positive on at least one ...
Tremblay GM, Ferland C, Lapointe JM, Vrins A, Lavoie JP, Cormier Y.Bronchoalveolar lavages (BAL) were performed before and after 3 weeks of housing in 5 horses suffering from COPD and 5 normal horses. In the two groups, the total number of cells recovered remained unchanged after stabling. The most common cell populations in BAL fluid of control animals were alveolar macrophages (46.4%) and lymphocytes (44.9%). The percentage of neutrophils increased after stabling from 8.7% to 27.6%. In COPD horses, lymphocytes predominated (40.7%) in animals at pasture with neutrophils increasing from 29.4% to 71.6% after stabling. After fractionation by Percoll density gra...
Uberti B, Morán G.Neutrophilic bronchiolitis is the primary lesion in asthma-affected horses. Neutrophils are key actors in host defense, migrating toward sites of inflammation and infection, where they act as early responder cells toward external insults. However, neutrophils can also mediate tissue damage in various non-infectious inflammatory processes. Within the airways, these cells likely contribute to bronchoconstriction, mucus hypersecretion, and pulmonary remodeling by releasing pro-inflammatory mediators, including the cytokines interleukin (IL)-8 and IL-17, neutrophil elastase, reactive oxygen specie...
Rosenberg HF, Druey KM.Asthma is a chronic, heterogeneous, and recurring inflammatory disease of the lower airways, with exacerbations that feature airway inflammation and bronchial hyperresponsiveness. Asthma has been modeled extensively via disease induction in both wild-type and genetically manipulated laboratory mice (Mus musculus). Antigen sensitization and challenge strategies have reproduced numerous important features of airway inflammation characteristic of human asthma, notably the critical roles of type 2 T helper cell cytokines. Recent models of disease induction have advanced to include physiologic aero...
Ghosh S, Das PJ, McQueen CM, Gerber V, Swiderski CE, Lavoie JP, Chowdhary BP, Raudsepp T.We explored the involvement of genomic copy number variants (CNVs) in susceptibility to recurrent airway obstruction (RAO), or heaves-an asthmalike inflammatory disease in horses. Analysis of 16 RAO-susceptible (cases) and six RAO-resistant (control) horses on a custom-made whole-genome 400K equine tiling array identified 245 CNV regions (CNVRs), 197 previously known and 48 new, distributed on all horse autosomes and the X chromosome. Among the new CNVRs, 30 were exclusively found in RAO cases and were further analyzed by quantitative PCR, including additional cases and controls. Suggestive as...
West JB, Mathieu-Costello O.The pulmonary blood-gas barrier has a basic physiological dilemma. On the one hand it needs to be extremely thin for efficient gas exchange. On the other hand it also needs to be immensely strong because the stresses on the pulmonary capillary wall become extremely high when the capillary pressure rises on exercise. Maximal hydrostatic pressures in human pulmonary capillaries during exercise are not accurately known but must exceed 30 mmHg. In some animals, for example thoroughbred horses, the capillary pressure rises to about 100 mmHg. These pressures cause stresses in the capillary wall of 5...
Gerber V, Robinson NE, Venta RJ, Rawson J, Jefcoat AM, Hotchkiss JA.Increased mucin gene expression may be an important cause of mucus accumulation observed in recurrent airway obstruction (RAO)-affected horses. To date, however, no mucin gene sequences are available for the horse. Objective: To identify equine homologues of gel-forming mucins and investigate their expression at different airway generations of healthy and RAO-affected horses. Methods: Two equine homologues were identified by cloning and sequencing fragments of equine (eq)MUC5AC and eqMUC2. Results: Semiquantitative RT-PCR on RNA from airways (generations 1, 5, 10, 15; small airways and parench...
Fogarty U, Buckley T.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.
Birks EK, Mathieu-Costello O, Fu Z, Tyler WS, West JB.In previous studies of rabbit and dog lung, we demonstrated stress failure of pulmonary capillaries at high transmural pressures (Ptm). The Ptm necessary to elicit stress failure was 40 cmH2O higher in dog than rabbit, and the total blood-gas barrier (BGB) thickness was greater in dog than rabbit. This suggests that stress failure may be related to BGB thickness, and is consistent with the Laplace relationship which states that wall stress is proportional to capillary radius but inversely proportional to wall thickness. In the present studies, we compared BGB thickness and an index of capillar...
Pirie RS, Collie DD, Dixon PM, McGorum BC.To evaluate inhaled hay dust suspensions (HDS) as a tool for the diagnosis and investigation of heaves, the pulmonary inflammatory and functional consequences of inhalation challenge with 3 different HDS were determined in 6 control and 7 asymptomatic heaves horses. Heaves horses given HDS challenge developed the characteristic features of heaves, including airway neutrophilia, obstructive airway dysfunction and mucus hypersecretion. While HDS challenge induced a mild airway neutrophilia in controls, the no-response threshold for controls was greater than that of heaves horses, and there was n...
Rush BR, Raub ES, Rhoads WS, Flaminio MJ, Matson CJ, Hakala JE, Gillespie JR.To determine changes in clinical signs of disease and response to pulmonary function testing in horses with recurrent airway obstruction (heaves) after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively. Methods: 6 horses with inducible and reversible heaves. Methods: Episodes of heaves were induced by exposure (challenge) to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone dipropionate, parenterally administered dexamethasone, aerosolized propellant [control]), and respiratory frequency and s...
McGorum BC, Dixon PM, Halliwell RE.Eight control and 8 asymptomatic COPD-affected horses were given, on separate occasions, inhalation challenges with extracts of Micropolyspora faeni, Aspergillus fumigatus and Thermoactinomyces vulgaris. All horses were also given nebulised phosphate-buffered saline (PBS) challenges and 'natural challenges' (NCs), i.e. exposure to hay and straw, as control challenges. Responses were assessed by clinical, pulmonary mechanics, arterial blood gas tensions, arterial blood pH and bronchoalveolar lavage fluid cytological examinations. PBS challenges had no effect on control or COPD-affected horses, ...
Connes P, Bouix D, Durand F, Kippelen P, Mercier J, Prefaut C, Brun JF, Caillaud C.Several studies have suggested that athletes with low hemoglobin saturation during exercise may experience impaired pulmonary blood gas exchange during maximal exercise. Blood viscosity may be implicated in exercise-induced pulmonary hemorrhage in race horses. We hypothesized that blood rheology may contribute to impaired gas exchange and reduced hemoglobin saturation during exercise in humans. A group of 20 highly trained endurance athletes participated in this study, 9 with low hemoglobin saturation during exercise (Low-SpO (2) group) and 11 with normal hemoglobin saturation (High-SpO (2) gr...
Bullone M, Chevigny M, Allano M, Martin JG, Lavoie JP.Morphometric analyses of endobronchial biopsies are commonly performed in asthma research but little is known about the technical and physiological parameters contributing to measurement variability. We investigated factors potentially affecting biopsy size, quality, and airway smooth muscle (ASM) content in heaves, an asthma-like disease of horses. Horses with heaves in clinical exacerbation (n = 6) or remission (n = 6) from the disease and six controls were studied using a crossover design. The effect of disease status, age, bronchodilation, biopsy forceps type, and carina size on total biop...
Derksen FJ, Olszewski MA, Robinson NE, Berney C, Hakala JE, Matson CJ, Ruth DT.To determine the dose of aerosolized albuterol sulfate required to cause bronchodilation in horses with recurrent airway obstruction (RAO) and duration of this effect. Methods: 19 horses with RAO (10 in experiment 1; 9 in experiment 2). Methods: Horses were moved from pasture to stables, and airway obstruction was induced. Pulmonary function was measured in 10 horses before and 5, 10, and 30 minutes after administration of vehicle or 120, 240, 360, or 720 microg of the drug. Nine horses received vehicle or 360 or 720 microg of albuterol, and pulmonary function was measured at baseline and 5 mi...
Parbhakar OP, Duke T, Townsend HG, Singh B.Horses are unique in their extreme sensitivity to endotoxin-induced cardio-pulmonary shock and mortality. The mechanisms behind increased sensitivity of the horse to endotoxin remain unknown. Pulmonary intravascular macrophages (PIMs) are pro-inflammatory cells occurring in horses. Because the functions of equine PIMs in endotoxemia remain unknown, we studied the role played by equine PIMs in endotoxin-induced pulmonary pathophysiology. We achieved this by using a recently developed protocol to deplete PIMs in order to compare lipopolysaccharide (LPS)-induced pulmonary responses in horses with...
Hare JE, Viel L.Horses are known to acquire small airway disease (SAD), an allergen-induced naturally occurring syndrome of reversible obstructive lung disease accompanied by airway hyperresponsiveness and increased inflammatory cell numbers on bronchoalveolar lavage (BAL). This disorder has received scant attention in young racehorses. The purpose of the present report was to examine the effect of BAL eosinophilia in young racehorses on clinical examination, BAL, hematology, airway responsiveness, and on pulmonary function at rest and after a standardized exercise challenge. Five (3 males, 2 females; age 2.6...
Derksen FJ, Scott JS, Miller DC, Slocombe RF, Robinson NE.We performed bronchoalveolar lavage (BAL) in 2 groups of ponies. Principal ponies had a history of heaves, a disease characterized by recurrent airway obstruction and airway hyperreactivity when ponies are housed in a barn and fed hay; control ponies had no history of airway obstruction. Ponies were paired (principal and control), and BAL was performed after 2 months of being pastured when principal ponies were in clinical remission (Period A), after barn housing when principal ponies had acute airway obstruction (Period B), and after a 1- and a 2-wk recovery phase of pasture grazing (Periods ...
Willoughby RA, McDonell WN.Pulmonary function tests in horses are in the early stages of development and there will be a limit in the range of tests available since those requiring patient cooperation cannot be conducted in animals. Some tests such as blood gas analysis, A-aDo2 and delta Ppl measurements could presently be used to a greater extent under field conditions. Others that require expensive equipment and considerable technical assistance will be limited to the larger referral type veterinary clinics until the time is reached when there is adequate information to select those procedures that give a reasonable c...
Rothschild CM, Oaks JL, Schaupp JK, Rurangirwa FR, Sellon DC, Hines MT.Helcococcus ovis, a recently described organism cultured from sheep, was isolated in pure culture from a pulmonary abscess in a horse. This is the first report of this organism in horses and the first report in veterinary medicine to clearly demonstrate a pathogenic role for this organism.
Venner M, Kerth R, Klug E.Tulathromycin is a new injectable macrolide antibiotic used for the treatment of pulmonary diseases of swine and cattle. In this study, 37 foals with sonographic evidence of lung abscesses were treated with tulathromycin (2.5mg/kg intramuscularly [IM] once weekly, group 1) and 33 foals (group 2) with a combination of azithromycin (10mg/kg per os [PO] once daily for the first seven days of therapy, thereafter every other day) and rifampin (10mg/kg PO twice daily). The bacterial aetiological agent was not determined. The foals were only mildly sick and the median number of pulmonary abscesses wa...
McKane SA, Canfield PJ, Rose RJ.Sixty-two Thoroughbred horses aged between 1 and 7 years in training in Sydney had bronchoalveolar lavage (BAL) samples collected for cytological examination. All horses, except the yearlings and those with a cough, had raced at the time of the examination and the trainers reported satisfactory performance. Free erythrocytes were found in 73% of samples and haemosiderophages in 90% of the samples, indicating immediate or past occurrences of exercise-induced pulmonary haemorrhage (EIPH). Bronchoalveolar fluid from the yearlings contained significantly less (P < 0.05) erythrocytes and haemosi...
Raulo SM, Sorsa T, Tervahartiala T, Pirilä E, Maisi P.Gelatinolytic activity was analysed to study whether elevated activity previously found at the tracheal level of the respiratory tract of horses with chronic obstructive pulmonary disease (COPD) could also be found at the lower part of the respiratory tract. Furthermore, presence and significance of the gelatinolytic matrix metalloproteinases (MMPs) MMP-2 and MMP-9 in respiratory secretions of healthy and COPD horses were determined. Elevated gelatinolytic matrix metalloproteinases were detected in bronchoalveolar and tracheobronchial secretions from COPD horses. The main pathologically elevat...
Meyer TS, Fedde MR, Gaughan EM, Langsetmo I, Erickson HH.Exercise-induced pulmonary haemorrhage (EIPH) causes serious economic losses in the horse racing industry. Endoscopic examination indicates that 40-90% of horses exhibit EIPH following sprint exercise, but the limitations of the endoscope prevent diagnosis in many horses. Bronchoalveolar lavage (BAL) was utilised to detect red blood cells (RBCs) in the terminal airways in 6 horses. Two lavages were performed at weekly intervals prior to exercise, one within 90 min after exercise, and 5 at weekly intervals after exercise. The horses were exercised strenuously at 12.5-14.6 m/s on a treadmill (3 ...
Klukowska-Rötzler J, Swinburne JE, Drögemüller C, Dolf G, Janda J, Leeb T, Gerber V.Recurrent airway obstruction (RAO) in horses is the result of an interaction of genetic and environmental factors and shares many characteristics with human asthma. Many studies have suggested that the interleukin-4 receptor gene (IL4R) is associated with this disease, and a QTL region on chromosome 13 containing IL4R was previously detected in one of the two Swiss Warmblood families. We sequenced the entire IL4R gene in this family and detected 93 variants including five non-synonymous protein-coding variants. The allele distribution at these SNPs supported the previously detected QTL signal....
van Erck E, Votion D, Art T, Lekeux P.Due to technical implementations and lack of sensitivity, pulmonary function tests are seldom used in clinical practice. Impulse oscillometry (IOS) could represent an alternative method. Objective: To define feasibility, methodology and repeatability of IOS, a forced oscillation technique that measures respiratory resistance (Rrs) and reactance (Xrs) from 5 to 35 Hz during spontaneous breathing, in horses. Methods: Using 38 healthy horses, Rrs and Xrs reference values were defined and influence of individual biometrical parameters was investigated. In addition, IOS measurements of 6 horses sho...
Venner M, Credner N, Lämmer M, Giguère S.The objectives of the present study were to determine the relative efficacy of tulathromycin, azithromycin, or azithromycin with rifampin for the treatment of pulmonary abscesses on a farm with endemic infections caused by Rhodococcus equi. Foals with ultrasonographic evidence of pulmonary abscesses (abscess score 8.0-15 cm; n=120) were randomly allocated in four equal treatment groups: (1) tulathromycin intramuscularly; (2) azithromycin monotherapy, orally; (3) azithromycin with rifampin, orally; (4) saline intramuscularly as a placebo. Physical examination and thoracic ultrasonography were p...
Riihimäki M, Raine A, Art T, Lekeux P, Couëtil L, Pringle J.The aim of this study was to investigate mRNA levels of cytokines in bronchial epithelium in horses with recurrent airway obstruction (RAO) during acute crisis and remission. Additionally, cytokine mRNA levels in endobronchial biopsies and bronchoalveolar lavage (BAL) cells were compared. Seven RAO horses were examined while in respiratory crisis following provocation and again while in remission after 2 months on pasture, during which time six healthy horses on pasture were also examined. Quantitative real-time PCR (RT-PCR) was used to assess mRNA expression for cytokines IL-5, IL-6, IL-8, IL...
Leclere M, Lavoie-Lamoureux A, Lavoie JP.Systemic inflammation is observed in horses with heaves and could also be present in horses with a lesser degree of pulmonary inflammation. Objective: It was hypothesized that racehorses with inflammatory airway disease (IAD) have increased concentration of circulating acute phase proteins. The objective of this study was to compare serum acute phase proteins of racehorses with and without lower airway inflammation. Methods: Serum from 21 client-owned Standardbred racehorses with exercise intolerance and lower airway inflammation and serum from 10 client-owned Standardbred racehorses with exer...
