Lung Function Variation during the Estrus Cycle of Mares Affected by Severe Asthma.
Authors: Mainguy-Seers Sophie, Diaw Mouhamadou, Lavoie Jean-Pierre
Journal: Animals : an open access journal from MDPI
Summary
# Editorial Summary: Estrus Cycle Effects on Equine Asthma Severe equine asthma (SEA) shows striking parallels to human asthma, where sex hormone fluctuations significantly influence disease severity—a phenomenon previously uninvestigated in mares. Mainguy-Seers and colleagues conducted a prospective study of five mares with naturally occurring SEA during active exacerbation, measuring whole-breath resistance, expiratory and inspiratory resistance, and reactance across follicular and luteal cycle phases, with concurrent ovarian characterisation via ultrasound and serum progesterone quantification. The most clinically relevant finding was improvement in inspiratory resistance and reactance during the luteal phase (when progesterone is elevated), alongside correlations between progesterone concentrations, dominant follicle diameter, and multiple lung function parameters. These results suggest that progesterone may have a protective effect on airway obstruction in SEA-affected mares, offering practitioners a measurable physiological basis for anticipating cyclical deteriorations in airway function during follicular phases and potentially timing interventions, medication adjustments, or exercise scheduling accordingly. Whilst this exploratory work is limited by its small sample size, it opens important questions about whether equine asthma could serve as a translational model for understanding hormonally mediated airway disease mechanisms, warranting larger prospective studies to establish robust clinical guidelines.
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Practical Takeaways
- •Monitor asthma exacerbations in mares with SEA in relation to their estrus cycle; expect potential worsening during follicular phase and improvement during luteal phase
- •Consider timing of veterinary interventions and management adjustments around the estrus cycle to optimize treatment efficacy in mares with severe respiratory disease
- •Document estrus cycle stage when evaluating lung function changes in mares with asthma to distinguish cycle-related variation from disease progression
Key Findings
- •Inspiratory resistance and reactance improved during the luteal phase compared to the follicular phase of the estrus cycle in mares with severe asthma
- •Progesterone level fluctuations correlated with multiple lung function parameters including expiratory resistance and whole breath resistance
- •Dominant follicle size variation correlated with several lung function measurements, suggesting hormonal influence on airway dysfunction
- •Airway obstruction severity varies cyclically in mares with severe equine asthma, paralleling patterns observed in human asthma patients