The influence of hay steaming on clinical signs and airway immune response in severe asthmatic horses

Marie Orard, Erika Hue, Anne Couroucé, Céline Bizon-Mercier, Marie-Pierre Toquet, Meriel Moore-Colyer, Laurent Couëtil, Stéphane Pronost, Romain Paillot, Magali Demoor, Eric A Richard

Research output: Contribution to journalJournal Articlepeer-review

7 Citations (Scopus)


BACKGROUND: Avoidance of antigenic stimuli was found to significantly reverse airway obstruction of horses with severe equine asthma (sEA). To date, no published study investigated the influence of steaming hay on lower airway condition of sEA-affected horses. The objectives were to determine the clinical, cytological and cytokine respiratory responses of both sEA and control (CTL) horses experimentally exposed to steamed or dry hay.

RESULTS: A cohort of 6 sEA horses and 6 CTL horses was involved in this field study. On day 0, both groups were fed with steamed hay for 5 consecutive days, followed by a wash-out period of 26 days prior to be fed with dry hay for 5 consecutive days. Investigations performed 2 days prior to and 5 days after each challenge included clinical score, tracheal mucus accumulation, and bronchoalveolar lavage fluid (BALF) cytology and cytokine mRNA expression. Feeding steamed hay significantly decreased its mould content (P < 0.001). Mucus score significantly increased when feeding dry hay (P = 0.01). No significant influence of challenge type was found on clinical score. Percentages of neutrophils (P < 0.001) as well as mRNA expression of IL-1β (P = 0.024), IL-6R (P = 0.021), IL-18 (P = 0.009) and IL-23 (P = 0.036) in BALF of sEA affected horses were significantly increased after both (steamed and dry hay) challenges. Relative mRNA expression of IL-1β, IL-6R and IL-23 in BALF were also significantly correlated to neutrophil percentages and both clinical and tracheal mucus score.

CONCLUSIONS: Steaming significantly decreased mould content but inconsistently influenced the respiratory response of sEA affected horses when fed hay. Based on BALF cytology and cytokine profiles, its relevance might be controversial as a non-medicinal therapy for sEA-affected horses.

Original languageEnglish
Pages (from-to)345
JournalBMC Veterinary Research
Issue number1
Publication statusPublished - 15 Nov 2018
Externally publishedYes


  • Air Microbiology
  • Animal Feed/adverse effects
  • Animals
  • Asthma/etiology
  • Bronchoalveolar Lavage Fluid/chemistry
  • Cytokines/metabolism
  • Female
  • Horse Diseases/etiology
  • Horses/immunology
  • Male
  • Steam
  • Trachea/metabolism


Dive into the research topics of 'The influence of hay steaming on clinical signs and airway immune response in severe asthmatic horses'. Together they form a unique fingerprint.

Cite this