Mild-moderate equine asthma: A scoping review of evidence supporting the consensus definition

Conturba

et al. 2022

Animals

Mild–moderate equine asthma (MEA) is a common respiratory disorder among racehorses, characterized by lower airway inflammation. Although it is generally agreed that MEA causes poor performance, contrasting results have been reported about the effects of tracheal mucus and the leukocyte populations of the bronchoalveolar lavage (BAL) on performance. This study aims to investigate the associations between airway inflammation and fitness parameters measured during an incremental treadmill test on Standardbred racehorses. For this purpose, the clinical records of 116 Standardbreds subjected to a diagnostic protocol for poor performance were retrospectively reviewed. Parametric and nonparametric statistics were used to evaluate the relationships between endoscopic scores, BAL cytological results, and fitness parameters. Moreover, horses were divided into MEA and non-MEA groups and into neutrophilic, eosinophilic–mastocytic, and mixed MEA groups; fitness parameters were compared between groups. Neutrophils percentages were inversely correlated with the speed at a heart rate of 200 bpm, the speed and heart rate at a plasma lactate concentration of 4 mmol/L (VLa4 and HRLa4), and the maximal speed, while they were positively correlated with higher lactate concentrations. Moreover, significant differences were detected between different MEA subtypes concerning VLa4, HRLa4, and lactate concentrations. These results suggest that airway neutrophilic inflammation impairs athletic capacity in Standardbreds.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Impact of Lower Airway Inflammation on Fitness Parameters in Standardbred Racehorses

Conturba

et al. 2022

Animals

“…Similarly, previously reported MEA prevalence in Standardbred racehorses in active training ranged from 58% to 97%, 1,15,54 which may be higher in a selected poorly‐performing population. In fact, MEA is universally recognized as 1 of the most common causes of impaired athletic capacity in horses 1,26,27 . Another common disorder of the lower airway is EIPH, which was assessed in our study by postexercise tracheobronchoscopy and calculation of THS in the BAL fluid.…”

Section: Discussionmentioning

confidence: 92%

“…In particular, for nonmusculoskeletal conditions, the treadmill velocity at which a blood lactate concentration of 4 mmol/L (VLa4) is reached and the treadmill velocity at a heart rate of 200 beats per minute (bpm; V200) are considered good indicators of the level of performance. [19][20][21][22] Musculoskeletal disorders are the most common cause of decreased performance in Standardbred racehorses, 2 followed by medical disorders such as respiratory diseases affecting the upper or lower airways, [1][2][3] including dynamic upper airway obstructions (DUAO), [23][24][25] mild to moderate equine asthma (MEA), 5,[26][27][28] and exercise-induced pulmonary hemorrhage (EIPH). [29][30][31][32] In fact, the respiratory system is considered the main limiting factor to performance even in healthy racehorses (both Thoroughbreds and Standardbreds), and related disorders can substantially impact the aerobic and athletic capacity of the horse.…”

Section: Introductionmentioning

confidence: 99%

Medical causes of poor performance and their associations with fitness in Standardbred racehorses

Veterinary Internal Medicne

Conturba

et al. 2023

Background Poor performance is a multifactorial syndrome of racehorses, commonly associated with subclinical disorders, which can be diagnosed by exercise testing. Objectives Describe the prevalence of medical causes of poor performance in Standardbreds unassociated with lameness, and evaluate their relationships with fitness variables measured by exercise treadmill test. Animals Hospital population of 259 nonlame Standardbred trotters referred for poor performance. Methods The horses' medical records were retrospectively reviewed. Horses underwent a diagnostic protocol including resting examination, plasma lactate concentration, treadmill test with continuous ECG and assessment of fitness variables, creatine kinase activity, treadmill endoscopy, postexercise tracheobronchoscopy, bronchoalveolar lavage (BAL), and gastroscopy. The prevalence of different disorders was evaluated, including cardiac arrhythmias, exertional myopathies, dynamic upper airway obstructions (DUAOs), exercise‐induced pulmonary hemorrhage (EIPH), moderate equine asthma (MEA), and gastric ulcers (EGUS). The associations of these disorders with fitness variables were investigated individually and using multivariable models. Results Moderate equine asthma and EGUS were the most common disorders, followed by EIPH, DUAOs, cardiac arrhythmias, and exertional myopathies. Hemosiderin score was positively correlated with BAL neutrophils, eosinophils, and mast cells; increased creatine kinase activity was associated with BAL neutrophilia, DUAOs, premature complexes, and squamous gastric disease. Treadmill velocity at a plasma lactate concentration of 4 mmol/L and at heart rate of 200 beats per minute was negatively affected by BAL neutrophilia, multiple DUAOs, exertional myopathies, and squamous gastric disease. Conclusions The multifactorial nature of poor performance was confirmed, with MEA, DUAOs, myopathies and EGUS representing the main diseases involved in fitness impairment.

“…The diagnosis, that could be only presumptive on the basis of clinical symptoms and airway endoscopy, relies on cytological examination of the bronchoalveolar lavage fluid (BALf), where a pathological accumulation of neutrophils and/or eosinophils and/or mast cells can be detected [ 2 , 4 ]. This condition, that may affect up to 80% of Thoroughbred racehorses in training, has been recently classified as a mild or moderate form of equine asthma (MEA), due to its similarities with human asthma [ 5 , 6 , 7 , 8 ]. The treatment of this disease is based, similarly to human asthma, on the administration of bronchodilators and corticosteroids, both systemic and by inhalation, in association with changes in the environmental management, aimed to reduce the respirable dust [ 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of the Administration of a Nutraceutical Supplement in Racehorses with Lower Airway Inflammation

Stancari

et al. 2022

Animals

Mild–moderate equine asthma (MEA) is a chronic inflammatory disorder of the lower airways of the horse, characterized by tracheal mucus accumulation, cough and poor performance. The therapeutic approach is based on pharmacological treatment and environmental management. Moreover, the efficacy of the administration of antioxidant molecules has been reported. The aim of the present study was to evaluate the effect of the administration of a commercial nutraceutical supplement, composed of several herbal extracts, on lower airway inflammation in racehorses. Twelve Thoroughbreds affected by MEA were selected. All horses underwent a clinical examination with assignment of a clinical score, airway endoscopy and cytological examination of bronchoalveolar lavage fluid. In seven horses, the supplement was administered for 21 days in association with environmental changes, while in five horses only environmental changes were performed. All procedures were repeated at the end of the study. Data concerning the clinical score, the endoscopic scores and the cytology at the beginning and at the end of the study were statistically compared. Data showed a significant reduction (p < 0.0156) of the clinical score and a significant reduction (p < 0.0156) of the tracheal mucus score. The results showed the beneficial effect of the supplement on mild–moderate lower airway inflammation, probably due to its antioxidant activity.