Steamed hay and alfalfa pellets for the management of severe equine asthma.
Authors: Symoens Antoine, Westerfeld Roxane, Vives Berta Mozo, André Valentine, Moulon Laurine, Collomb Marine, Richard Hélène, Juette Tristan, Bédard Christian, Leclère Mathilde
Journal: Equine veterinary journal
Summary
# Steamed Hay versus Alfalfa Pellets for Severe Equine Asthma Severe equine asthma (SEA) remains a significant management challenge, and whilst steaming hay reduces respirable particle exposure, clinical evidence supporting its use has been limited. Researchers enrolled nine horses with SEA in a controlled crossover study, feeding each animal both alfalfa pellets and steamed hay for four-week periods during exacerbation whilst measuring clinical scores, lung resistance, and airway inflammation via bronchoalveolar lavage fluid (BALF) cytology weekly. Alfalfa pellets demonstrated superior efficacy: clinical scores improved more markedly (from median 13 to 2 versus 10 to 6 with steamed hay), and lung resistance fell more dramatically and consistently across all four weeks (baseline 2.62 cmH₂O/L/s declining to 0.62 by week 4, compared to steamed hay's improvement only through week 2). Both diets reduced BALF neutrophil percentages significantly, indicating reduced airway inflammation, though the effect was greater with pellets (40.2% to 20.1% versus 30.9% to 25.7%). For practitioners managing SEA, these findings suggest alfalfa pellets offer superior functional improvement in lung mechanics, whilst acknowledging that steamed hay remains a viable option where pellets are unavailable or unpalatable, particularly given its modest clinical and inflammatory benefits.
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Practical Takeaways
- •Both steamed hay and alfalfa pellets improve clinical signs and reduce airway inflammation in horses with severe asthma, but pellets produce faster and more sustained improvements in lung function
- •If transitioning horses with SEA to alternative forage, alfalfa pellets may provide superior respiratory benefits compared to steamed hay alone, though steamed hay still offers clinical improvement
- •Consider pellet-based feeding systems for asthmatic horses requiring rapid stabilization, while steamed hay may serve as a palatable complementary option
Key Findings
- •Weighted clinical scores improved significantly over time with both diets (p<0.001), decreasing from 13 to 2 with pellets and from 10 to 6 with steamed hay
- •Lung resistance decreased more dramatically with pellets (2.62 to 0.62 cmH2O/L/s over 4 weeks) compared to steamed hay (2.34 to 1.38-1.51 cmH2O/L/s over 2 weeks)
- •Neutrophil counts in bronchoalveolar lavage fluid decreased significantly with both diets (pellets: 40.2% to 20.1%; steamed hay: 30.9% to 25.7%; p=0.006)
- •Alfalfa pellets demonstrated more pronounced improvements in lung function compared to steamed hay over the 4-week treatment period