The incidence of asthma—cough, labored breathing and exercise intolerance—in adult horses ranges from 10–20%. A retrospective, case-control study at Texas A&M from January 2014 to December 2018 reviewed various factors that might pose or reveal a risk for development of equine asthma: Signalment, dietary and stable management, medical history, metabolic status, physical exam and cytology from bronchoalveolar lavage or tracheal wash. Only one statistically significant risk factor was identified for asthma in the 74 horses: Obesity [Thomas, S.J.; de Solis, C.N.; Coleman, M.C. Case-Control Study of Risk Factors for Equine Asthma in Texas. Journal of Equine Veterinary Science, 2021; doi.org/10.1016/j.jevs.2021.103644].
Through a grant from the Morris Animal Foundation, TexasA &M University is researching this potential link between obesity and equine asthma. The rationale for investigating this possible association is based on a correlation of obesity with human asthma. The relevance for horses is important because obese and/or endocrine dysfunctional horses should not be medicated with corticosteroids due to the potential to elicit laminitis. Identifying if there is an association between obesity and asthma might then emphasize a safer preventive strategy and remedy through weight loss regimens and dietary control.
The study to be performed at the Texas A&M Veterinary Medical Teaching Hospital will evaluate 60 horses for body condition score, insulin function and degree of asthma assessed with airway auscultation, nasal discharge, cytology and analysis of lower airway fluid samples. There will be four groups of 15 horses in each group: a) obese + asthmatic; b) non-obese + asthmatic; c) obese + healthy; d) non-obese + healthy. Cytokines and other inflammatory markers will be measured in each horse. In addition, lung bacteria (microbiota) of asthmatic horses will be evaluated to compare differences between obese and non-obese animals.