Texas Equine Veterinary Association

www.texasequineva.com | 14 Non-infectious respiratory disease in performance horses remains costly and challenging to manage and has the capability to diminish the athletic capability of these horses. e negative effects on a performance career in horses diagnosed with exercise-induced pulmonary hemorrhage (EIPH) and equine asthma have been clearly documented in racehorses (Hinchcliff et al., 2015). In contrast, limited information is available on non-infectious respiratory diseases in barrel-racing horses, the interaction between EIPH and asthma, and the impact on the horse's performance (Gold et al., 2018; Léguillette et al., 2016; Newton and Wood, 2002). EIPH can be diagnosed by visualization of active bleeding from the nares immediately following intense exercise, by upper airway endoscopic examination of the trachea, and by presence of hemosiderophages or frank blood in bronchioalveolar lavage (BAL) fluid (Hinchcliff et al., 2015). Equine asthma is diagnosed by BAL fluid cytological evaluation, and can be categorized by a variety of characteristics, including severity (inflammatory airway disease versus recurrent airway obstruction) or predominant cell type (mastocytic, neutrophilic, or eosinophilic) (Couëtil et al., 2016). Pulmonary function testing has a useful role in research; however, the applicability to clinical practice remains unclear and less accessible (Bond et al., 2018). Few studies have evaluated both EIPH and asthma within a single equine population or temporally within an individual horse (da Silva et al., 2017). Both diseases are commonly found in performance horses and the proposed pathophysiology may be interconnected. e presence of blood in the lung may act as a local irritant and may induce an inflammatory response that is consistent with mild equine asthma (McKane and Slocombe, 2010; Sullivan and Hinchcliff, 2015). Bronchoconstriction due to the presence of an irritant leads to elevated intrapleural pressure and may increase the risk of EIPH (da Silva et al., 2017). Additionally, long-term exposure to an irritant (such as red blood cells secondary to EIPH) may result in scar tissue formation within the lung parenchyma, resulting in reduced tissue compliance and increased intrapleural pressure (da Silva et al., 2017). Horses used in barrel-racing are predominately Quarter Horses, or Quarter Horse- Exercise-induced pulmonary hemorrhage & equine asthma Laszlo Hunyadi, DVM, MS, DACVIM (LAIM) Professor of Large Animal Internal Medicine & Tropical Medicine Texas Tech University School of Veterinary Medicine Amarillo, TX Laszlo Hunyadi is a professor of large animal internal medicine and originally from El Paso, TX near Sunland Park, NM. He is a diplomat of the American College of Veterinary Internal Medicine, Large Animal. His teaching focuses on all aspects of internal medicine, infectious diseases and diagnostic clinical workups. His research area is on pharmacokinetic and dynamics of new equine therapeutics, exercise intolerance in western performance horses as it pertains to asthma, and validating the accuracy of new diagnostics for emerging and existing infectious diseases. He is the AAEP Vaccine Guidelines Chair, and member of the Infectious Disease Committee. He also serves on the ACVIM clinical management Exam Writing Task Force. He volunteers his time doing equitarian outreach with Full Bucket to serve rural areas in Guatemala and with the Rural Area Veterinary Services to provide clinical work to under served areas on Native American Reservations. Currently, he is working with the AAEP to update all the vaccine guidelines for equine practitioners.

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